execPartition.c

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * execPartition.c
 *    Support routines for partitioning.
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/executor/execPartition.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "access/table.h"
#include "access/tableam.h"
#include "catalog/index.h"
#include "catalog/partition.h"
#include "executor/execPartition.h"
#include "executor/executor.h"
#include "executor/nodeModifyTable.h"
#include "foreign/fdwapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "partitioning/partbounds.h"
#include "partitioning/partdesc.h"
#include "partitioning/partprune.h"
#include "rewrite/rewriteManip.h"
#include "utils/acl.h"
#include "utils/injection_point.h"
#include "utils/lsyscache.h"
#include "utils/partcache.h"
#include "utils/rls.h"
#include "utils/ruleutils.h"
 
 
/*-----------------------
 * PartitionTupleRouting - Encapsulates all information required to
 * route a tuple inserted into a partitioned table to one of its leaf
 * partitions.
 *
 * partition_root
 *      The partitioned table that's the target of the command.
 *
 * partition_dispatch_info
 *      Array of 'max_dispatch' elements containing a pointer to a
 *      PartitionDispatch object for every partitioned table touched by tuple
 *      routing.  The entry for the target partitioned table is *always*
 *      present in the 0th element of this array.  See comment for
 *      PartitionDispatchData->indexes for details on how this array is
 *      indexed.
 *
 * nonleaf_partitions
 *      Array of 'max_dispatch' elements containing pointers to fake
 *      ResultRelInfo objects for nonleaf partitions, useful for checking
 *      the partition constraint.
 *
 * num_dispatch
 *      The current number of items stored in the 'partition_dispatch_info'
 *      array.  Also serves as the index of the next free array element for
 *      new PartitionDispatch objects that need to be stored.
 *
 * max_dispatch
 *      The current allocated size of the 'partition_dispatch_info' array.
 *
 * partitions
 *      Array of 'max_partitions' elements containing a pointer to a
 *      ResultRelInfo for every leaf partition touched by tuple routing.
 *      Some of these are pointers to ResultRelInfos which are borrowed out of
 *      the owning ModifyTableState node.  The remainder have been built
 *      especially for tuple routing.  See comment for
 *      PartitionDispatchData->indexes for details on how this array is
 *      indexed.
 *
 * is_borrowed_rel
 *      Array of 'max_partitions' booleans recording whether a given entry
 *      in 'partitions' is a ResultRelInfo pointer borrowed from the owning
 *      ModifyTableState node, rather than being built here.
 *
 * num_partitions
 *      The current number of items stored in the 'partitions' array.  Also
 *      serves as the index of the next free array element for new
 *      ResultRelInfo objects that need to be stored.
 *
 * max_partitions
 *      The current allocated size of the 'partitions' array.
 *
 * memcxt
 *      Memory context used to allocate subsidiary structs.
 *-----------------------
 */
struct PartitionTupleRouting
{
    Relation    partition_root;
    PartitionDispatch *partition_dispatch_info;
    ResultRelInfo **nonleaf_partitions;
    int         num_dispatch;
    int         max_dispatch;
    ResultRelInfo **partitions;
    bool       *is_borrowed_rel;
    int         num_partitions;
    int         max_partitions;
    MemoryContext memcxt;
};
 
/*-----------------------
 * PartitionDispatch - information about one partitioned table in a partition
 * hierarchy required to route a tuple to any of its partitions.  A
 * PartitionDispatch is always encapsulated inside a PartitionTupleRouting
 * struct and stored inside its 'partition_dispatch_info' array.
 *
 * reldesc
 *      Relation descriptor of the table
 *
 * key
 *      Partition key information of the table
 *
 * keystate
 *      Execution state required for expressions in the partition key
 *
 * partdesc
 *      Partition descriptor of the table
 *
 * tupslot
 *      A standalone TupleTableSlot initialized with this table's tuple
 *      descriptor, or NULL if no tuple conversion between the parent is
 *      required.
 *
 * tupmap
 *      TupleConversionMap to convert from the parent's rowtype to this table's
 *      rowtype  (when extracting the partition key of a tuple just before
 *      routing it through this table). A NULL value is stored if no tuple
 *      conversion is required.
 *
 * indexes
 *      Array of partdesc->nparts elements.  For leaf partitions the index
 *      corresponds to the partition's ResultRelInfo in the encapsulating
 *      PartitionTupleRouting's partitions array.  For partitioned partitions,
 *      the index corresponds to the PartitionDispatch for it in its
 *      partition_dispatch_info array.  -1 indicates we've not yet allocated
 *      anything in PartitionTupleRouting for the partition.
 *-----------------------
 */
typedef struct PartitionDispatchData
{
    Relation    reldesc;
    PartitionKey key;
    List       *keystate;       /* list of ExprState */
    PartitionDesc partdesc;
    TupleTableSlot *tupslot;
    AttrMap    *tupmap;
    int         indexes[FLEXIBLE_ARRAY_MEMBER];
}           PartitionDispatchData;
 
 
static ResultRelInfo *ExecInitPartitionInfo(ModifyTableState *mtstate,
                                            EState *estate, PartitionTupleRouting *proute,
                                            PartitionDispatch dispatch,
                                            ResultRelInfo *rootResultRelInfo,
                                            int partidx);
static void ExecInitRoutingInfo(ModifyTableState *mtstate,
                                EState *estate,
                                PartitionTupleRouting *proute,
                                PartitionDispatch dispatch,
                                ResultRelInfo *partRelInfo,
                                int partidx,
                                bool is_borrowed_rel);
static PartitionDispatch ExecInitPartitionDispatchInfo(EState *estate,
                                                       PartitionTupleRouting *proute,
                                                       Oid partoid, PartitionDispatch parent_pd,
                                                       int partidx, ResultRelInfo *rootResultRelInfo);
static void FormPartitionKeyDatum(PartitionDispatch pd,
                                  TupleTableSlot *slot,
                                  EState *estate,
                                  Datum *values,
                                  bool *isnull);
static int  get_partition_for_tuple(PartitionDispatch pd, const Datum *values,
                                    const bool *isnull);
static char *ExecBuildSlotPartitionKeyDescription(Relation rel,
                                                  const Datum *values,
                                                  const bool *isnull,
                                                  int maxfieldlen);
static List *adjust_partition_colnos(List *colnos, ResultRelInfo *leaf_part_rri);
static List *adjust_partition_colnos_using_map(List *colnos, AttrMap *attrMap);
static PartitionPruneState *CreatePartitionPruneState(EState *estate,
                                                      PartitionPruneInfo *pruneinfo,
                                                      Bitmapset **all_leafpart_rtis);
static void InitPartitionPruneContext(PartitionPruneContext *context,
                                      List *pruning_steps,
                                      PartitionDesc partdesc,
                                      PartitionKey partkey,
                                      PlanState *planstate,
                                      ExprContext *econtext);
static void InitExecPartitionPruneContexts(PartitionPruneState *prunestate,
                                           PlanState *parent_plan,
                                           Bitmapset *initially_valid_subplans,
                                           int n_total_subplans);
static void find_matching_subplans_recurse(PartitionPruningData *prunedata,
                                           PartitionedRelPruningData *pprune,
                                           bool initial_prune,
                                           Bitmapset **validsubplans,
                                           Bitmapset **validsubplan_rtis);
 
 
/*
 * ExecSetupPartitionTupleRouting - sets up information needed during
 * tuple routing for partitioned tables, encapsulates it in
 * PartitionTupleRouting, and returns it.
 *
 * Callers must use the returned PartitionTupleRouting during calls to
 * ExecFindPartition().  The actual ResultRelInfo for a partition is only
 * allocated when the partition is found for the first time.
 *
 * The current memory context is used to allocate this struct and all
 * subsidiary structs that will be allocated from it later on.  Typically
 * it should be estate->es_query_cxt.
 */
PartitionTupleRouting *
ExecSetupPartitionTupleRouting(EState *estate, Relation rel)
{
    PartitionTupleRouting *proute;
 
    /*
     * Here we attempt to expend as little effort as possible in setting up
     * the PartitionTupleRouting.  Each partition's ResultRelInfo is built on
     * demand, only when we actually need to route a tuple to that partition.
     * The reason for this is that a common case is for INSERT to insert a
     * single tuple into a partitioned table and this must be fast.
     */
    proute = palloc0_object(PartitionTupleRouting);
    proute->partition_root = rel;
    proute->memcxt = CurrentMemoryContext;
    /* Rest of members initialized by zeroing */
 
    /*
     * Initialize this table's PartitionDispatch object.  Here we pass in the
     * parent as NULL as we don't need to care about any parent of the target
     * partitioned table.
     */
    ExecInitPartitionDispatchInfo(estate, proute, RelationGetRelid(rel),
                                  NULL, 0, NULL);
 
    return proute;
}
 
/*
 * ExecFindPartition -- Return the ResultRelInfo for the leaf partition that
 * the tuple contained in *slot should belong to.
 *
 * If the partition's ResultRelInfo does not yet exist in 'proute' then we set
 * one up or reuse one from mtstate's resultRelInfo array.  When reusing a
 * ResultRelInfo from the mtstate we verify that the relation is a valid
 * target for INSERTs and initialize tuple routing information.
 *
 * rootResultRelInfo is the relation named in the query.
 *
 * estate must be non-NULL; we'll need it to compute any expressions in the
 * partition keys.  Also, its per-tuple contexts are used as evaluation
 * scratch space.
 *
 * If no leaf partition is found, this routine errors out with the appropriate
 * error message.  An error may also be raised if the found target partition
 * is not a valid target for an INSERT.
 */
ResultRelInfo *
ExecFindPartition(ModifyTableState *mtstate,
                  ResultRelInfo *rootResultRelInfo,
                  PartitionTupleRouting *proute,
                  TupleTableSlot *slot, EState *estate)
{
    PartitionDispatch *pd = proute->partition_dispatch_info;
    Datum       values[PARTITION_MAX_KEYS];
    bool        isnull[PARTITION_MAX_KEYS];
    Relation    rel;
    PartitionDispatch dispatch;
    PartitionDesc partdesc;
    ExprContext *ecxt = GetPerTupleExprContext(estate);
    TupleTableSlot *ecxt_scantuple_saved = ecxt->ecxt_scantuple;
    TupleTableSlot *rootslot = slot;
    TupleTableSlot *myslot = NULL;
    MemoryContext oldcxt;
    ResultRelInfo *rri = NULL;
 
    /* use per-tuple context here to avoid leaking memory */
    oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
 
    /*
     * First check the root table's partition constraint, if any.  No point in
     * routing the tuple if it doesn't belong in the root table itself.
     */
    if (rootResultRelInfo->ri_RelationDesc->rd_rel->relispartition)
        ExecPartitionCheck(rootResultRelInfo, slot, estate, true);
 
    /* start with the root partitioned table */
    dispatch = pd[0];
    while (dispatch != NULL)
    {
        int         partidx = -1;
        bool        is_leaf;
 
        CHECK_FOR_INTERRUPTS();
 
        rel = dispatch->reldesc;
        partdesc = dispatch->partdesc;
 
        /*
         * Extract partition key from tuple. Expression evaluation machinery
         * that FormPartitionKeyDatum() invokes expects ecxt_scantuple to
         * point to the correct tuple slot.  The slot might have changed from
         * what was used for the parent table if the table of the current
         * partitioning level has different tuple descriptor from the parent.
         * So update ecxt_scantuple accordingly.
         */
        ecxt->ecxt_scantuple = slot;
        FormPartitionKeyDatum(dispatch, slot, estate, values, isnull);
 
        /*
         * If this partitioned table has no partitions or no partition for
         * these values, error out.
         */
        if (partdesc->nparts == 0 ||
            (partidx = get_partition_for_tuple(dispatch, values, isnull)) < 0)
        {
            char       *val_desc;
 
            val_desc = ExecBuildSlotPartitionKeyDescription(rel,
                                                            values, isnull, 64);
            Assert(OidIsValid(RelationGetRelid(rel)));
            ereport(ERROR,
                    (errcode(ERRCODE_CHECK_VIOLATION),
                     errmsg("no partition of relation \"%s\" found for row",
                            RelationGetRelationName(rel)),
                     val_desc ?
                     errdetail("Partition key of the failing row contains %s.",
                               val_desc) : 0,
                     errtable(rel)));
        }
 
        is_leaf = partdesc->is_leaf[partidx];
        if (is_leaf)
        {
            /*
             * We've reached the leaf -- hurray, we're done.  Look to see if
             * we've already got a ResultRelInfo for this partition.
             */
            if (likely(dispatch->indexes[partidx] >= 0))
            {
                /* ResultRelInfo already built */
                Assert(dispatch->indexes[partidx] < proute->num_partitions);
                rri = proute->partitions[dispatch->indexes[partidx]];
            }
            else
            {
                /*
                 * If the partition is known in the owning ModifyTableState
                 * node, we can re-use that ResultRelInfo instead of creating
                 * a new one with ExecInitPartitionInfo().
                 */
                rri = ExecLookupResultRelByOid(mtstate,
                                               partdesc->oids[partidx],
                                               true, false);
                if (rri)
                {
                    ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
 
                    /* Verify this ResultRelInfo allows INSERTs */
                    CheckValidResultRel(rri, CMD_INSERT,
                                        node ? node->onConflictAction : ONCONFLICT_NONE,
                                        NIL);
 
                    /*
                     * Initialize information needed to insert this and
                     * subsequent tuples routed to this partition.
                     */
                    ExecInitRoutingInfo(mtstate, estate, proute, dispatch,
                                        rri, partidx, true);
                }
                else
                {
                    /* We need to create a new one. */
                    rri = ExecInitPartitionInfo(mtstate, estate, proute,
                                                dispatch,
                                                rootResultRelInfo, partidx);
                }
            }
            Assert(rri != NULL);
 
            /* Signal to terminate the loop */
            dispatch = NULL;
        }
        else
        {
            /*
             * Partition is a sub-partitioned table; get the PartitionDispatch
             */
            if (likely(dispatch->indexes[partidx] >= 0))
            {
                /* Already built. */
                Assert(dispatch->indexes[partidx] < proute->num_dispatch);
 
                rri = proute->nonleaf_partitions[dispatch->indexes[partidx]];
 
                /*
                 * Move down to the next partition level and search again
                 * until we find a leaf partition that matches this tuple
                 */
                dispatch = pd[dispatch->indexes[partidx]];
            }
            else
            {
                /* Not yet built. Do that now. */
                PartitionDispatch subdispatch;
 
                /*
                 * Create the new PartitionDispatch.  We pass the current one
                 * in as the parent PartitionDispatch
                 */
                subdispatch = ExecInitPartitionDispatchInfo(estate,
                                                            proute,
                                                            partdesc->oids[partidx],
                                                            dispatch, partidx,
                                                            mtstate->rootResultRelInfo);
                Assert(dispatch->indexes[partidx] >= 0 &&
                       dispatch->indexes[partidx] < proute->num_dispatch);
 
                rri = proute->nonleaf_partitions[dispatch->indexes[partidx]];
                dispatch = subdispatch;
            }
 
            /*
             * Convert the tuple to the new parent's layout, if different from
             * the previous parent.
             */
            if (dispatch->tupslot)
            {
                AttrMap    *map = dispatch->tupmap;
                TupleTableSlot *tempslot = myslot;
 
                myslot = dispatch->tupslot;
                slot = execute_attr_map_slot(map, slot, myslot);
 
                if (tempslot != NULL)
                    ExecClearTuple(tempslot);
            }
        }
 
        /*
         * If this partition is the default one, we must check its partition
         * constraint now, which may have changed concurrently due to
         * partitions being added to the parent.
         *
         * (We do this here, and do not rely on ExecInsert doing it, because
         * we don't want to miss doing it for non-leaf partitions.)
         */
        if (partidx == partdesc->boundinfo->default_index)
        {
            /*
             * The tuple must match the partition's layout for the constraint
             * expression to be evaluated successfully.  If the partition is
             * sub-partitioned, that would already be the case due to the code
             * above, but for a leaf partition the tuple still matches the
             * parent's layout.
             *
             * Note that we have a map to convert from root to current
             * partition, but not from immediate parent to current partition.
             * So if we have to convert, do it from the root slot; if not, use
             * the root slot as-is.
             */
            if (is_leaf)
            {
                TupleConversionMap *map = ExecGetRootToChildMap(rri, estate);
 
                if (map)
                    slot = execute_attr_map_slot(map->attrMap, rootslot,
                                                 rri->ri_PartitionTupleSlot);
                else
                    slot = rootslot;
            }
 
            ExecPartitionCheck(rri, slot, estate, true);
        }
    }
 
    /* Release the tuple in the lowest parent's dedicated slot. */
    if (myslot != NULL)
        ExecClearTuple(myslot);
    /* and restore ecxt's scantuple */
    ecxt->ecxt_scantuple = ecxt_scantuple_saved;
    MemoryContextSwitchTo(oldcxt);
 
    return rri;
}
 
/*
 * IsIndexCompatibleAsArbiter
 *      Return true if two indexes are identical for INSERT ON CONFLICT
 *      purposes.
 *
 * Only indexes of the same relation are supported.
 */
static bool
IsIndexCompatibleAsArbiter(Relation arbiterIndexRelation,
                           IndexInfo *arbiterIndexInfo,
                           Relation indexRelation,
                           IndexInfo *indexInfo)
{
    Assert(arbiterIndexRelation->rd_index->indrelid == indexRelation->rd_index->indrelid);
 
    /* must match whether they're unique */
    if (arbiterIndexInfo->ii_Unique != indexInfo->ii_Unique)
        return false;
 
    /* No support currently for comparing exclusion indexes. */
    if (arbiterIndexInfo->ii_ExclusionOps != NULL ||
        indexInfo->ii_ExclusionOps != NULL)
        return false;
 
    /* the "nulls not distinct" criterion must match */
    if (arbiterIndexInfo->ii_NullsNotDistinct !=
        indexInfo->ii_NullsNotDistinct)
        return false;
 
    /* number of key attributes must match */
    if (arbiterIndexInfo->ii_NumIndexKeyAttrs !=
        indexInfo->ii_NumIndexKeyAttrs)
        return false;
 
    for (int i = 0; i < arbiterIndexInfo->ii_NumIndexKeyAttrs; i++)
    {
        if (arbiterIndexRelation->rd_indcollation[i] !=
            indexRelation->rd_indcollation[i])
            return false;
 
        if (arbiterIndexRelation->rd_opfamily[i] !=
            indexRelation->rd_opfamily[i])
            return false;
 
        if (arbiterIndexRelation->rd_index->indkey.values[i] !=
            indexRelation->rd_index->indkey.values[i])
            return false;
    }
 
    if (list_difference(RelationGetIndexExpressions(arbiterIndexRelation),
                        RelationGetIndexExpressions(indexRelation)) != NIL)
        return false;
 
    if (list_difference(RelationGetIndexPredicate(arbiterIndexRelation),
                        RelationGetIndexPredicate(indexRelation)) != NIL)
        return false;
    return true;
}
 
/*
 * ExecInitPartitionInfo
 *      Lock the partition and initialize ResultRelInfo.  Also setup other
 *      information for the partition and store it in the next empty slot in
 *      the proute->partitions array.
 *
 * Returns the ResultRelInfo
 */
static ResultRelInfo *
ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
                      PartitionTupleRouting *proute,
                      PartitionDispatch dispatch,
                      ResultRelInfo *rootResultRelInfo,
                      int partidx)
{
    ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
    Oid         partOid = dispatch->partdesc->oids[partidx];
    Relation    partrel;
    int         firstVarno = mtstate->resultRelInfo[0].ri_RangeTableIndex;
    Relation    firstResultRel = mtstate->resultRelInfo[0].ri_RelationDesc;
    ResultRelInfo *leaf_part_rri;
    MemoryContext oldcxt;
    AttrMap    *part_attmap = NULL;
    bool        found_whole_row;
 
    oldcxt = MemoryContextSwitchTo(proute->memcxt);
 
    partrel = table_open(partOid, RowExclusiveLock);
 
    leaf_part_rri = makeNode(ResultRelInfo);
    InitResultRelInfo(leaf_part_rri,
                      partrel,
                      0,
                      rootResultRelInfo,
                      estate->es_instrument);
 
    /*
     * Verify result relation is a valid target for an INSERT.  An UPDATE of a
     * partition-key becomes a DELETE+INSERT operation, so this check is still
     * required when the operation is CMD_UPDATE.
     */
    CheckValidResultRel(leaf_part_rri, CMD_INSERT,
                        node ? node->onConflictAction : ONCONFLICT_NONE, NIL);
 
    /*
     * Open partition indices.  The user may have asked to check for conflicts
     * within this leaf partition and do "nothing" instead of throwing an
     * error.  Be prepared in that case by initializing the index information
     * needed by ExecInsert() to perform speculative insertions.
     */
    if (partrel->rd_rel->relhasindex &&
        leaf_part_rri->ri_IndexRelationDescs == NULL)
        ExecOpenIndices(leaf_part_rri,
                        (node != NULL &&
                         node->onConflictAction != ONCONFLICT_NONE));
 
    /*
     * Build WITH CHECK OPTION constraints for the partition.  Note that we
     * didn't build the withCheckOptionList for partitions within the planner,
     * but simple translation of varattnos will suffice.  This only occurs for
     * the INSERT case or in the case of UPDATE/MERGE tuple routing where we
     * didn't find a result rel to reuse.
     */
    if (node && node->withCheckOptionLists != NIL)
    {
        List       *wcoList;
        List       *wcoExprs = NIL;
        ListCell   *ll;
 
        /*
         * In the case of INSERT on a partitioned table, there is only one
         * plan.  Likewise, there is only one WCO list, not one per partition.
         * For UPDATE/MERGE, there are as many WCO lists as there are plans.
         */
        Assert((node->operation == CMD_INSERT &&
                list_length(node->withCheckOptionLists) == 1 &&
                list_length(node->resultRelations) == 1) ||
               (node->operation == CMD_UPDATE &&
                list_length(node->withCheckOptionLists) ==
                list_length(node->resultRelations)) ||
               (node->operation == CMD_MERGE &&
                list_length(node->withCheckOptionLists) ==
                list_length(node->resultRelations)));
 
        /*
         * Use the WCO list of the first plan as a reference to calculate
         * attno's for the WCO list of this partition.  In the INSERT case,
         * that refers to the root partitioned table, whereas in the UPDATE
         * tuple routing case, that refers to the first partition in the
         * mtstate->resultRelInfo array.  In any case, both that relation and
         * this partition should have the same columns, so we should be able
         * to map attributes successfully.
         */
        wcoList = linitial(node->withCheckOptionLists);
 
        /*
         * Convert Vars in it to contain this partition's attribute numbers.
         */
        part_attmap =
            build_attrmap_by_name(RelationGetDescr(partrel),
                                  RelationGetDescr(firstResultRel),
                                  false);
        wcoList = (List *)
            map_variable_attnos((Node *) wcoList,
                                firstVarno, 0,
                                part_attmap,
                                RelationGetForm(partrel)->reltype,
                                &found_whole_row);
        /* We ignore the value of found_whole_row. */
 
        foreach(ll, wcoList)
        {
            WithCheckOption *wco = lfirst_node(WithCheckOption, ll);
            ExprState  *wcoExpr = ExecInitQual(castNode(List, wco->qual),
                                               &mtstate->ps);
 
            wcoExprs = lappend(wcoExprs, wcoExpr);
        }
 
        leaf_part_rri->ri_WithCheckOptions = wcoList;
        leaf_part_rri->ri_WithCheckOptionExprs = wcoExprs;
    }
 
    /*
     * Build the RETURNING projection for the partition.  Note that we didn't
     * build the returningList for partitions within the planner, but simple
     * translation of varattnos will suffice.  This only occurs for the INSERT
     * case or in the case of UPDATE/MERGE tuple routing where we didn't find
     * a result rel to reuse.
     */
    if (node && node->returningLists != NIL)
    {
        TupleTableSlot *slot;
        ExprContext *econtext;
        List       *returningList;
 
        /* See the comment above for WCO lists. */
        Assert((node->operation == CMD_INSERT &&
                list_length(node->returningLists) == 1 &&
                list_length(node->resultRelations) == 1) ||
               (node->operation == CMD_UPDATE &&
                list_length(node->returningLists) ==
                list_length(node->resultRelations)) ||
               (node->operation == CMD_MERGE &&
                list_length(node->returningLists) ==
                list_length(node->resultRelations)));
 
        /*
         * Use the RETURNING list of the first plan as a reference to
         * calculate attno's for the RETURNING list of this partition.  See
         * the comment above for WCO lists for more details on why this is
         * okay.
         */
        returningList = linitial(node->returningLists);
 
        /*
         * Convert Vars in it to contain this partition's attribute numbers.
         */
        if (part_attmap == NULL)
            part_attmap =
                build_attrmap_by_name(RelationGetDescr(partrel),
                                      RelationGetDescr(firstResultRel),
                                      false);
        returningList = (List *)
            map_variable_attnos((Node *) returningList,
                                firstVarno, 0,
                                part_attmap,
                                RelationGetForm(partrel)->reltype,
                                &found_whole_row);
        /* We ignore the value of found_whole_row. */
 
        leaf_part_rri->ri_returningList = returningList;
 
        /*
         * Initialize the projection itself.
         *
         * Use the slot and the expression context that would have been set up
         * in ExecInitModifyTable() for projection's output.
         */
        Assert(mtstate->ps.ps_ResultTupleSlot != NULL);
        slot = mtstate->ps.ps_ResultTupleSlot;
        Assert(mtstate->ps.ps_ExprContext != NULL);
        econtext = mtstate->ps.ps_ExprContext;
        leaf_part_rri->ri_projectReturning =
            ExecBuildProjectionInfo(returningList, econtext, slot,
                                    &mtstate->ps, RelationGetDescr(partrel));
    }
 
    /* Set up information needed for routing tuples to the partition. */
    ExecInitRoutingInfo(mtstate, estate, proute, dispatch,
                        leaf_part_rri, partidx, false);
 
    /*
     * If there is an ON CONFLICT clause, initialize state for it.
     */
    if (node && node->onConflictAction != ONCONFLICT_NONE)
    {
        TupleDesc   partrelDesc = RelationGetDescr(partrel);
        ExprContext *econtext = mtstate->ps.ps_ExprContext;
        List       *arbiterIndexes = NIL;
        int         additional_arbiters = 0;
 
        /*
         * If there is a list of arbiter indexes, map it to a list of indexes
         * in the partition.  We also add any "identical indexes" to any of
         * those, to cover the case where one of them is concurrently being
         * reindexed.
         */
        if (rootResultRelInfo->ri_onConflictArbiterIndexes != NIL)
        {
            List       *unparented_idxs = NIL,
                       *arbiters_listidxs = NIL,
                       *ancestors_seen = NIL;
 
            for (int listidx = 0; listidx < leaf_part_rri->ri_NumIndices; listidx++)
            {
                Oid         indexoid;
                List       *ancestors;
 
                /*
                 * If one of this index's ancestors is in the root's arbiter
                 * list, then use this index as arbiter for this partition.
                 * Otherwise, if this index has no parent, track it for later,
                 * in case REINDEX CONCURRENTLY is working on one of the
                 * arbiters.
                 *
                 * However, if two indexes appear to have the same parent,
                 * treat the second of these as if it had no parent.  This
                 * sounds counterintuitive, but it can happen if a transaction
                 * running REINDEX CONCURRENTLY commits right between those
                 * two indexes are checked by another process in this loop.
                 * This will have the effect of also treating that second
                 * index as arbiter.
                 *
                 * XXX get_partition_ancestors scans pg_inherits, which is not
                 * only slow, but also means the catalog snapshot can get
                 * invalidated each time through the loop (cf.
                 * GetNonHistoricCatalogSnapshot).  Consider a syscache or
                 * some other way to cache?
                 */
                indexoid = RelationGetRelid(leaf_part_rri->ri_IndexRelationDescs[listidx]);
                ancestors = get_partition_ancestors(indexoid);
                INJECTION_POINT("exec-init-partition-after-get-partition-ancestors", NULL);
 
                if (ancestors != NIL &&
                    !list_member_oid(ancestors_seen, linitial_oid(ancestors)))
                {
                    foreach_oid(parent_idx, rootResultRelInfo->ri_onConflictArbiterIndexes)
                    {
                        if (list_member_oid(ancestors, parent_idx))
                        {
                            ancestors_seen = lappend_oid(ancestors_seen, linitial_oid(ancestors));
                            arbiterIndexes = lappend_oid(arbiterIndexes, indexoid);
                            arbiters_listidxs = lappend_int(arbiters_listidxs, listidx);
                            break;
                        }
                    }
                }
                else
                    unparented_idxs = lappend_int(unparented_idxs, listidx);
 
                list_free(ancestors);
            }
 
            /*
             * If we found any indexes with no ancestors, it's possible that
             * some arbiter index is undergoing concurrent reindex.  Match all
             * unparented indexes against arbiters; add unparented matching
             * ones as "additional arbiters".
             *
             * This is critical so that all concurrent transactions use the
             * same set as arbiters during REINDEX CONCURRENTLY, to avoid
             * spurious "duplicate key" errors.
             */
            if (unparented_idxs && arbiterIndexes)
            {
                foreach_int(unparented_i, unparented_idxs)
                {
                    Relation    unparented_rel;
                    IndexInfo  *unparented_ii;
 
                    unparented_rel = leaf_part_rri->ri_IndexRelationDescs[unparented_i];
                    unparented_ii = leaf_part_rri->ri_IndexRelationInfo[unparented_i];
 
                    Assert(!list_member_oid(arbiterIndexes,
                                            unparented_rel->rd_index->indexrelid));
 
                    /* Ignore indexes not ready */
                    if (!unparented_ii->ii_ReadyForInserts)
                        continue;
 
                    foreach_int(arbiter_i, arbiters_listidxs)
                    {
                        Relation    arbiter_rel;
                        IndexInfo  *arbiter_ii;
 
                        arbiter_rel = leaf_part_rri->ri_IndexRelationDescs[arbiter_i];
                        arbiter_ii = leaf_part_rri->ri_IndexRelationInfo[arbiter_i];
 
                        /*
                         * If the non-ancestor index is compatible with the
                         * arbiter, use the non-ancestor as arbiter too.
                         */
                        if (IsIndexCompatibleAsArbiter(arbiter_rel,
                                                       arbiter_ii,
                                                       unparented_rel,
                                                       unparented_ii))
                        {
                            arbiterIndexes = lappend_oid(arbiterIndexes,
                                                         unparented_rel->rd_index->indexrelid);
                            additional_arbiters++;
                            break;
                        }
                    }
                }
            }
            list_free(unparented_idxs);
            list_free(arbiters_listidxs);
            list_free(ancestors_seen);
        }
 
        /*
         * We expect to find as many arbiter indexes on this partition as the
         * root has, plus however many "additional arbiters" (to wit: those
         * being concurrently rebuilt) we found.
         */
        if (list_length(rootResultRelInfo->ri_onConflictArbiterIndexes) !=
            list_length(arbiterIndexes) - additional_arbiters)
            elog(ERROR, "invalid arbiter index list");
        leaf_part_rri->ri_onConflictArbiterIndexes = arbiterIndexes;
 
        /*
         * In the DO UPDATE and DO SELECT cases, we have some more state to
         * initialize.
         */
        if (node->onConflictAction == ONCONFLICT_UPDATE ||
            node->onConflictAction == ONCONFLICT_SELECT)
        {
            OnConflictActionState *onconfl = makeNode(OnConflictActionState);
            TupleConversionMap *map;
 
            map = ExecGetRootToChildMap(leaf_part_rri, estate);
 
            Assert(node->onConflictSet != NIL ||
                   node->onConflictAction == ONCONFLICT_SELECT);
            Assert(rootResultRelInfo->ri_onConflict != NULL);
 
            leaf_part_rri->ri_onConflict = onconfl;
 
            /* Lock strength for DO SELECT [FOR UPDATE/SHARE] */
            onconfl->oc_LockStrength =
                rootResultRelInfo->ri_onConflict->oc_LockStrength;
 
            /*
             * Need a separate existing slot for each partition, as the
             * partition could be of a different AM, even if the tuple
             * descriptors match.
             */
            onconfl->oc_Existing =
                table_slot_create(leaf_part_rri->ri_RelationDesc,
                                  &mtstate->ps.state->es_tupleTable);
 
            /*
             * If the partition's tuple descriptor matches exactly the root
             * parent (the common case), we can re-use most of the parent's ON
             * CONFLICT action state, skipping a bunch of work.  Otherwise, we
             * need to create state specific to this partition.
             */
            if (map == NULL)
            {
                /*
                 * It's safe to reuse these from the partition root, as we
                 * only process one tuple at a time (therefore we won't
                 * overwrite needed data in slots), and the results of any
                 * projections are independent of the underlying storage.
                 * Projections and where clauses themselves don't store state
                 * / are independent of the underlying storage.
                 */
                onconfl->oc_ProjSlot =
                    rootResultRelInfo->ri_onConflict->oc_ProjSlot;
                onconfl->oc_ProjInfo =
                    rootResultRelInfo->ri_onConflict->oc_ProjInfo;
                onconfl->oc_WhereClause =
                    rootResultRelInfo->ri_onConflict->oc_WhereClause;
            }
            else
            {
                /*
                 * For ON CONFLICT DO UPDATE, translate expressions in
                 * onConflictSet to account for different attribute numbers.
                 * For that, map partition varattnos twice: first to catch the
                 * EXCLUDED pseudo-relation (INNER_VAR), and second to handle
                 * the main target relation (firstVarno).
                 */
                if (node->onConflictAction == ONCONFLICT_UPDATE)
                {
                    List       *onconflset;
                    List       *onconflcols;
 
                    onconflset = copyObject(node->onConflictSet);
                    if (part_attmap == NULL)
                        part_attmap =
                            build_attrmap_by_name(RelationGetDescr(partrel),
                                                  RelationGetDescr(firstResultRel),
                                                  false);
                    onconflset = (List *)
                        map_variable_attnos((Node *) onconflset,
                                            INNER_VAR, 0,
                                            part_attmap,
                                            RelationGetForm(partrel)->reltype,
                                            &found_whole_row);
                    /* We ignore the value of found_whole_row. */
                    onconflset = (List *)
                        map_variable_attnos((Node *) onconflset,
                                            firstVarno, 0,
                                            part_attmap,
                                            RelationGetForm(partrel)->reltype,
                                            &found_whole_row);
                    /* We ignore the value of found_whole_row. */
 
                    /*
                     * Finally, adjust the target colnos to match the
                     * partition.
                     */
                    onconflcols = adjust_partition_colnos(node->onConflictCols,
                                                          leaf_part_rri);
 
                    /* create the tuple slot for the UPDATE SET projection */
                    onconfl->oc_ProjSlot =
                        table_slot_create(partrel,
                                          &mtstate->ps.state->es_tupleTable);
 
                    /* build UPDATE SET projection state */
                    onconfl->oc_ProjInfo =
                        ExecBuildUpdateProjection(onconflset,
                                                  true,
                                                  onconflcols,
                                                  partrelDesc,
                                                  econtext,
                                                  onconfl->oc_ProjSlot,
                                                  &mtstate->ps);
                }
 
                /*
                 * For both ON CONFLICT DO UPDATE and ON CONFLICT DO SELECT,
                 * there may be a WHERE clause.  If so, initialize state where
                 * it will be evaluated, mapping the attribute numbers
                 * appropriately.  As with onConflictSet, we need to map
                 * partition varattnos twice, to catch both the EXCLUDED
                 * pseudo-relation (INNER_VAR), and the main target relation
                 * (firstVarno).
                 */
                if (node->onConflictWhere)
                {
                    List       *clause;
 
                    if (part_attmap == NULL)
                        part_attmap =
                            build_attrmap_by_name(RelationGetDescr(partrel),
                                                  RelationGetDescr(firstResultRel),
                                                  false);
 
                    clause = copyObject((List *) node->onConflictWhere);
                    clause = (List *)
                        map_variable_attnos((Node *) clause,
                                            INNER_VAR, 0,
                                            part_attmap,
                                            RelationGetForm(partrel)->reltype,
                                            &found_whole_row);
                    /* We ignore the value of found_whole_row. */
                    clause = (List *)
                        map_variable_attnos((Node *) clause,
                                            firstVarno, 0,
                                            part_attmap,
                                            RelationGetForm(partrel)->reltype,
                                            &found_whole_row);
                    /* We ignore the value of found_whole_row. */
                    onconfl->oc_WhereClause =
                        ExecInitQual(clause, &mtstate->ps);
                }
            }
        }
    }
 
    /*
     * Since we've just initialized this ResultRelInfo, it's not in any list
     * attached to the estate as yet.  Add it, so that it can be found later.
     *
     * Note that the entries in this list appear in no predetermined order,
     * because partition result rels are initialized as and when they're
     * needed.
     */
    MemoryContextSwitchTo(estate->es_query_cxt);
    estate->es_tuple_routing_result_relations =
        lappend(estate->es_tuple_routing_result_relations,
                leaf_part_rri);
 
    /*
     * Initialize information about this partition that's needed to handle
     * MERGE.  We take the "first" result relation's mergeActionList as
     * reference and make copy for this relation, converting stuff that
     * references attribute numbers to match this relation's.
     *
     * This duplicates much of the logic in ExecInitMerge(), so if something
     * changes there, look here too.
     */
    if (node && node->operation == CMD_MERGE)
    {
        List       *firstMergeActionList = linitial(node->mergeActionLists);
        ListCell   *lc;
        ExprContext *econtext = mtstate->ps.ps_ExprContext;
        Node       *joinCondition;
 
        if (part_attmap == NULL)
            part_attmap =
                build_attrmap_by_name(RelationGetDescr(partrel),
                                      RelationGetDescr(firstResultRel),
                                      false);
 
        if (unlikely(!leaf_part_rri->ri_projectNewInfoValid))
            ExecInitMergeTupleSlots(mtstate, leaf_part_rri);
 
        /* Initialize state for join condition checking. */
        joinCondition =
            map_variable_attnos(linitial(node->mergeJoinConditions),
                                firstVarno, 0,
                                part_attmap,
                                RelationGetForm(partrel)->reltype,
                                &found_whole_row);
        /* We ignore the value of found_whole_row. */
        leaf_part_rri->ri_MergeJoinCondition =
            ExecInitQual((List *) joinCondition, &mtstate->ps);
 
        foreach(lc, firstMergeActionList)
        {
            /* Make a copy for this relation to be safe.  */
            MergeAction *action = copyObject(lfirst(lc));
            MergeActionState *action_state;
 
            /* Generate the action's state for this relation */
            action_state = makeNode(MergeActionState);
            action_state->mas_action = action;
 
            /* And put the action in the appropriate list */
            leaf_part_rri->ri_MergeActions[action->matchKind] =
                lappend(leaf_part_rri->ri_MergeActions[action->matchKind],
                        action_state);
 
            switch (action->commandType)
            {
                case CMD_INSERT:
 
                    /*
                     * ExecCheckPlanOutput() already done on the targetlist
                     * when "first" result relation initialized and it is same
                     * for all result relations.
                     */
                    action_state->mas_proj =
                        ExecBuildProjectionInfo(action->targetList, econtext,
                                                leaf_part_rri->ri_newTupleSlot,
                                                &mtstate->ps,
                                                RelationGetDescr(partrel));
                    break;
                case CMD_UPDATE:
 
                    /*
                     * Convert updateColnos from "first" result relation
                     * attribute numbers to this result rel's.
                     */
                    if (part_attmap)
                        action->updateColnos =
                            adjust_partition_colnos_using_map(action->updateColnos,
                                                              part_attmap);
                    action_state->mas_proj =
                        ExecBuildUpdateProjection(action->targetList,
                                                  true,
                                                  action->updateColnos,
                                                  RelationGetDescr(leaf_part_rri->ri_RelationDesc),
                                                  econtext,
                                                  leaf_part_rri->ri_newTupleSlot,
                                                  NULL);
                    break;
                case CMD_DELETE:
                case CMD_NOTHING:
                    /* Nothing to do */
                    break;
 
                default:
                    elog(ERROR, "unknown action in MERGE WHEN clause");
            }
 
            /* found_whole_row intentionally ignored. */
            action->qual =
                map_variable_attnos(action->qual,
                                    firstVarno, 0,
                                    part_attmap,
                                    RelationGetForm(partrel)->reltype,
                                    &found_whole_row);
            action_state->mas_whenqual =
                ExecInitQual((List *) action->qual, &mtstate->ps);
        }
    }
    MemoryContextSwitchTo(oldcxt);
 
    return leaf_part_rri;
}
 
/*
 * ExecInitRoutingInfo
 *      Set up information needed for translating tuples between root
 *      partitioned table format and partition format, and keep track of it
 *      in PartitionTupleRouting.
 */
static void
ExecInitRoutingInfo(ModifyTableState *mtstate,
                    EState *estate,
                    PartitionTupleRouting *proute,
                    PartitionDispatch dispatch,
                    ResultRelInfo *partRelInfo,
                    int partidx,
                    bool is_borrowed_rel)
{
    MemoryContext oldcxt;
    int         rri_index;
 
    oldcxt = MemoryContextSwitchTo(proute->memcxt);
 
    /*
     * Set up tuple conversion between root parent and the partition if the
     * two have different rowtypes.  If conversion is indeed required, also
     * initialize a slot dedicated to storing this partition's converted
     * tuples.  Various operations that are applied to tuples after routing,
     * such as checking constraints, will refer to this slot.
     */
    if (ExecGetRootToChildMap(partRelInfo, estate) != NULL)
    {
        Relation    partrel = partRelInfo->ri_RelationDesc;
 
        /*
         * This pins the partition's TupleDesc, which will be released at the
         * end of the command.
         */
        partRelInfo->ri_PartitionTupleSlot =
            table_slot_create(partrel, &estate->es_tupleTable);
    }
    else
        partRelInfo->ri_PartitionTupleSlot = NULL;
 
    /*
     * If the partition is a foreign table, let the FDW init itself for
     * routing tuples to the partition.
     */
    if (partRelInfo->ri_FdwRoutine != NULL &&
        partRelInfo->ri_FdwRoutine->BeginForeignInsert != NULL)
        partRelInfo->ri_FdwRoutine->BeginForeignInsert(mtstate, partRelInfo);
 
    /*
     * Determine if the FDW supports batch insert and determine the batch size
     * (a FDW may support batching, but it may be disabled for the
     * server/table or for this particular query).
     *
     * If the FDW does not support batching, we set the batch size to 1.
     */
    if (partRelInfo->ri_FdwRoutine != NULL &&
        partRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize &&
        partRelInfo->ri_FdwRoutine->ExecForeignBatchInsert)
        partRelInfo->ri_BatchSize =
            partRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize(partRelInfo);
    else
        partRelInfo->ri_BatchSize = 1;
 
    Assert(partRelInfo->ri_BatchSize >= 1);
 
    partRelInfo->ri_CopyMultiInsertBuffer = NULL;
 
    /*
     * Keep track of it in the PartitionTupleRouting->partitions array.
     */
    Assert(dispatch->indexes[partidx] == -1);
 
    rri_index = proute->num_partitions++;
 
    /* Allocate or enlarge the array, as needed */
    if (proute->num_partitions >= proute->max_partitions)
    {
        if (proute->max_partitions == 0)
        {
            proute->max_partitions = 8;
            proute->partitions = palloc_array(ResultRelInfo *, proute->max_partitions);
            proute->is_borrowed_rel = palloc_array(bool, proute->max_partitions);
        }
        else
        {
            proute->max_partitions *= 2;
            proute->partitions = (ResultRelInfo **)
                repalloc(proute->partitions, sizeof(ResultRelInfo *) *
                         proute->max_partitions);
            proute->is_borrowed_rel = (bool *)
                repalloc(proute->is_borrowed_rel, sizeof(bool) *
                         proute->max_partitions);
        }
    }
 
    proute->partitions[rri_index] = partRelInfo;
    proute->is_borrowed_rel[rri_index] = is_borrowed_rel;
    dispatch->indexes[partidx] = rri_index;
 
    MemoryContextSwitchTo(oldcxt);
}
 
/*
 * ExecInitPartitionDispatchInfo
 *      Lock the partitioned table (if not locked already) and initialize
 *      PartitionDispatch for a partitioned table and store it in the next
 *      available slot in the proute->partition_dispatch_info array.  Also,
 *      record the index into this array in the parent_pd->indexes[] array in
 *      the partidx element so that we can properly retrieve the newly created
 *      PartitionDispatch later.
 */
static PartitionDispatch
ExecInitPartitionDispatchInfo(EState *estate,
                              PartitionTupleRouting *proute, Oid partoid,
                              PartitionDispatch parent_pd, int partidx,
                              ResultRelInfo *rootResultRelInfo)
{
    Relation    rel;
    PartitionDesc partdesc;
    PartitionDispatch pd;
    int         dispatchidx;
    MemoryContext oldcxt;
 
    /*
     * For data modification, it is better that executor does not include
     * partitions being detached, except when running in snapshot-isolation
     * mode.  This means that a read-committed transaction immediately gets a
     * "no partition for tuple" error when a tuple is inserted into a
     * partition that's being detached concurrently, but a transaction in
     * repeatable-read mode can still use such a partition.
     */
    if (estate->es_partition_directory == NULL)
        estate->es_partition_directory =
            CreatePartitionDirectory(estate->es_query_cxt,
                                     !IsolationUsesXactSnapshot());
 
    oldcxt = MemoryContextSwitchTo(proute->memcxt);
 
    /*
     * Only sub-partitioned tables need to be locked here.  The root
     * partitioned table will already have been locked as it's referenced in
     * the query's rtable.
     */
    if (partoid != RelationGetRelid(proute->partition_root))
        rel = table_open(partoid, RowExclusiveLock);
    else
        rel = proute->partition_root;
    partdesc = PartitionDirectoryLookup(estate->es_partition_directory, rel);
 
    pd = (PartitionDispatch) palloc(offsetof(PartitionDispatchData, indexes) +
                                    partdesc->nparts * sizeof(int));
    pd->reldesc = rel;
    pd->key = RelationGetPartitionKey(rel);
    pd->keystate = NIL;
    pd->partdesc = partdesc;
    if (parent_pd != NULL)
    {
        TupleDesc   tupdesc = RelationGetDescr(rel);
 
        /*
         * For sub-partitioned tables where the column order differs from its
         * direct parent partitioned table, we must store a tuple table slot
         * initialized with its tuple descriptor and a tuple conversion map to
         * convert a tuple from its parent's rowtype to its own.  This is to
         * make sure that we are looking at the correct row using the correct
         * tuple descriptor when computing its partition key for tuple
         * routing.
         */
        pd->tupmap = build_attrmap_by_name_if_req(RelationGetDescr(parent_pd->reldesc),
                                                  tupdesc,
                                                  false);
        pd->tupslot = pd->tupmap ?
            MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual) : NULL;
    }
    else
    {
        /* Not required for the root partitioned table */
        pd->tupmap = NULL;
        pd->tupslot = NULL;
    }
 
    /*
     * Initialize with -1 to signify that the corresponding partition's
     * ResultRelInfo or PartitionDispatch has not been created yet.
     */
    memset(pd->indexes, -1, sizeof(int) * partdesc->nparts);
 
    /* Track in PartitionTupleRouting for later use */
    dispatchidx = proute->num_dispatch++;
 
    /* Allocate or enlarge the array, as needed */
    if (proute->num_dispatch >= proute->max_dispatch)
    {
        if (proute->max_dispatch == 0)
        {
            proute->max_dispatch = 4;
            proute->partition_dispatch_info = palloc_array(PartitionDispatch, proute->max_dispatch);
            proute->nonleaf_partitions = palloc_array(ResultRelInfo *, proute->max_dispatch);
        }
        else
        {
            proute->max_dispatch *= 2;
            proute->partition_dispatch_info = (PartitionDispatch *)
                repalloc(proute->partition_dispatch_info,
                         sizeof(PartitionDispatch) * proute->max_dispatch);
            proute->nonleaf_partitions = (ResultRelInfo **)
                repalloc(proute->nonleaf_partitions,
                         sizeof(ResultRelInfo *) * proute->max_dispatch);
        }
    }
    proute->partition_dispatch_info[dispatchidx] = pd;
 
    /*
     * If setting up a PartitionDispatch for a sub-partitioned table, we may
     * also need a minimally valid ResultRelInfo for checking the partition
     * constraint later; set that up now.
     */
    if (parent_pd)
    {
        ResultRelInfo *rri = makeNode(ResultRelInfo);
 
        InitResultRelInfo(rri, rel, 0, rootResultRelInfo, 0);
        proute->nonleaf_partitions[dispatchidx] = rri;
    }
    else
        proute->nonleaf_partitions[dispatchidx] = NULL;
 
    /*
     * Finally, if setting up a PartitionDispatch for a sub-partitioned table,
     * install a downlink in the parent to allow quick descent.
     */
    if (parent_pd)
    {
        Assert(parent_pd->indexes[partidx] == -1);
        parent_pd->indexes[partidx] = dispatchidx;
    }
 
    MemoryContextSwitchTo(oldcxt);
 
    return pd;
}
 
/*
 * ExecCleanupTupleRouting -- Clean up objects allocated for partition tuple
 * routing.
 *
 * Close all the partitioned tables, leaf partitions, and their indices.
 */
void
ExecCleanupTupleRouting(ModifyTableState *mtstate,
                        PartitionTupleRouting *proute)
{
    int         i;
 
    /*
     * Remember, proute->partition_dispatch_info[0] corresponds to the root
     * partitioned table, which we must not try to close, because it is the
     * main target table of the query that will be closed by callers such as
     * ExecEndPlan() or DoCopy(). Also, tupslot is NULL for the root
     * partitioned table.
     */
    for (i = 1; i < proute->num_dispatch; i++)
    {
        PartitionDispatch pd = proute->partition_dispatch_info[i];
 
        table_close(pd->reldesc, NoLock);
 
        if (pd->tupslot)
            ExecDropSingleTupleTableSlot(pd->tupslot);
    }
 
    for (i = 0; i < proute->num_partitions; i++)
    {
        ResultRelInfo *resultRelInfo = proute->partitions[i];
 
        /* Allow any FDWs to shut down */
        if (resultRelInfo->ri_FdwRoutine != NULL &&
            resultRelInfo->ri_FdwRoutine->EndForeignInsert != NULL)
            resultRelInfo->ri_FdwRoutine->EndForeignInsert(mtstate->ps.state,
                                                           resultRelInfo);
 
        /*
         * Close it if it's not one of the result relations borrowed from the
         * owning ModifyTableState; those will be closed by ExecEndPlan().
         */
        if (proute->is_borrowed_rel[i])
            continue;
 
        ExecCloseIndices(resultRelInfo);
        table_close(resultRelInfo->ri_RelationDesc, NoLock);
    }
}
 
/* ----------------
 *      FormPartitionKeyDatum
 *          Construct values[] and isnull[] arrays for the partition key
 *          of a tuple.
 *
 *  pd              Partition dispatch object of the partitioned table
 *  slot            Heap tuple from which to extract partition key
 *  estate          executor state for evaluating any partition key
 *                  expressions (must be non-NULL)
 *  values          Array of partition key Datums (output area)
 *  isnull          Array of is-null indicators (output area)
 *
 * the ecxt_scantuple slot of estate's per-tuple expr context must point to
 * the heap tuple passed in.
 * ----------------
 */
static void
FormPartitionKeyDatum(PartitionDispatch pd,
                      TupleTableSlot *slot,
                      EState *estate,
                      Datum *values,
                      bool *isnull)
{
    ListCell   *partexpr_item;
    int         i;
 
    if (pd->key->partexprs != NIL && pd->keystate == NIL)
    {
        /* Check caller has set up context correctly */
        Assert(estate != NULL &&
               GetPerTupleExprContext(estate)->ecxt_scantuple == slot);
 
        /* First time through, set up expression evaluation state */
        pd->keystate = ExecPrepareExprList(pd->key->partexprs, estate);
    }
 
    partexpr_item = list_head(pd->keystate);
    for (i = 0; i < pd->key->partnatts; i++)
    {
        AttrNumber  keycol = pd->key->partattrs[i];
        Datum       datum;
        bool        isNull;
 
        if (keycol != 0)
        {
            /* Plain column; get the value directly from the heap tuple */
            datum = slot_getattr(slot, keycol, &isNull);
        }
        else
        {
            /* Expression; need to evaluate it */
            if (partexpr_item == NULL)
                elog(ERROR, "wrong number of partition key expressions");
            datum = ExecEvalExprSwitchContext((ExprState *) lfirst(partexpr_item),
                                              GetPerTupleExprContext(estate),
                                              &isNull);
            partexpr_item = lnext(pd->keystate, partexpr_item);
        }
        values[i] = datum;
        isnull[i] = isNull;
    }
 
    if (partexpr_item != NULL)
        elog(ERROR, "wrong number of partition key expressions");
}
 
/*
 * The number of times the same partition must be found in a row before we
 * switch from a binary search for the given values to just checking if the
 * values belong to the last found partition.  This must be above 0.
 */
#define PARTITION_CACHED_FIND_THRESHOLD         16
 
/*
 * get_partition_for_tuple
 *      Finds partition of relation which accepts the partition key specified
 *      in values and isnull.
 *
 * Calling this function can be quite expensive when LIST and RANGE
 * partitioned tables have many partitions.  This is due to the binary search
 * that's done to find the correct partition.  Many of the use cases for LIST
 * and RANGE partitioned tables make it likely that the same partition is
 * found in subsequent ExecFindPartition() calls.  This is especially true for
 * cases such as RANGE partitioned tables on a TIMESTAMP column where the
 * partition key is the current time.  When asked to find a partition for a
 * RANGE or LIST partitioned table, we record the partition index and datum
 * offset we've found for the given 'values' in the PartitionDesc (which is
 * stored in relcache), and if we keep finding the same partition
 * PARTITION_CACHED_FIND_THRESHOLD times in a row, then we'll enable caching
 * logic and instead of performing a binary search to find the correct
 * partition, we'll just double-check that 'values' still belong to the last
 * found partition, and if so, we'll return that partition index, thus
 * skipping the need for the binary search.  If we fail to match the last
 * partition when double checking, then we fall back on doing a binary search.
 * In this case, unless we find 'values' belong to the DEFAULT partition,
 * we'll reset the number of times we've hit the same partition so that we
 * don't attempt to use the cache again until we've found that partition at
 * least PARTITION_CACHED_FIND_THRESHOLD times in a row.
 *
 * For cases where the partition changes on each lookup, the amount of
 * additional work required just amounts to recording the last found partition
 * and bound offset then resetting the found counter.  This is cheap and does
 * not appear to cause any meaningful slowdowns for such cases.
 *
 * No caching of partitions is done when the last found partition is the
 * DEFAULT or NULL partition.  For the case of the DEFAULT partition, there
 * is no bound offset storing the matching datum, so we cannot confirm the
 * indexes match.  For the NULL partition, this is just so cheap, there's no
 * sense in caching.
 *
 * Return value is index of the partition (>= 0 and < partdesc->nparts) if one
 * found or -1 if none found.
 */
static int
get_partition_for_tuple(PartitionDispatch pd, const Datum *values, const bool *isnull)
{
    int         bound_offset = -1;
    int         part_index = -1;
    PartitionKey key = pd->key;
    PartitionDesc partdesc = pd->partdesc;
    PartitionBoundInfo boundinfo = partdesc->boundinfo;
 
    /*
     * In the switch statement below, when we perform a cached lookup for
     * RANGE and LIST partitioned tables, if we find that the last found
     * partition matches the 'values', we return the partition index right
     * away.  We do this instead of breaking out of the switch as we don't
     * want to execute the code about the DEFAULT partition or do any updates
     * for any of the cache-related fields.  That would be a waste of effort
     * as we already know it's not the DEFAULT partition and have no need to
     * increment the number of times we found the same partition any higher
     * than PARTITION_CACHED_FIND_THRESHOLD.
     */
 
    /* Route as appropriate based on partitioning strategy. */
    switch (key->strategy)
    {
        case PARTITION_STRATEGY_HASH:
            {
                uint64      rowHash;
 
                /* hash partitioning is too cheap to bother caching */
                rowHash = compute_partition_hash_value(key->partnatts,
                                                       key->partsupfunc,
                                                       key->partcollation,
                                                       values, isnull);
 
                /*
                 * HASH partitions can't have a DEFAULT partition and we don't
                 * do any caching work for them, so just return the part index
                 */
                return boundinfo->indexes[rowHash % boundinfo->nindexes];
            }
 
        case PARTITION_STRATEGY_LIST:
            if (isnull[0])
            {
                /* this is far too cheap to bother doing any caching */
                if (partition_bound_accepts_nulls(boundinfo))
                {
                    /*
                     * When there is a NULL partition we just return that
                     * directly.  We don't have a bound_offset so it's not
                     * valid to drop into the code after the switch which
                     * checks and updates the cache fields.  We perhaps should
                     * be invalidating the details of the last cached
                     * partition but there's no real need to.  Keeping those
                     * fields set gives a chance at matching to the cached
                     * partition on the next lookup.
                     */
                    return boundinfo->null_index;
                }
            }
            else
            {
                bool        equal;
 
                if (partdesc->last_found_count >= PARTITION_CACHED_FIND_THRESHOLD)
                {
                    int         last_datum_offset = partdesc->last_found_datum_index;
                    Datum       lastDatum = boundinfo->datums[last_datum_offset][0];
                    int32       cmpval;
 
                    /* does the last found datum index match this datum? */
                    cmpval = DatumGetInt32(FunctionCall2Coll(&key->partsupfunc[0],
                                                             key->partcollation[0],
                                                             lastDatum,
                                                             values[0]));
 
                    if (cmpval == 0)
                        return boundinfo->indexes[last_datum_offset];
 
                    /* fall-through and do a manual lookup */
                }
 
                bound_offset = partition_list_bsearch(key->partsupfunc,
                                                      key->partcollation,
                                                      boundinfo,
                                                      values[0], &equal);
                if (bound_offset >= 0 && equal)
                    part_index = boundinfo->indexes[bound_offset];
            }
            break;
 
        case PARTITION_STRATEGY_RANGE:
            {
                bool        equal = false,
                            range_partkey_has_null = false;
                int         i;
 
                /*
                 * No range includes NULL, so this will be accepted by the
                 * default partition if there is one, and otherwise rejected.
                 */
                for (i = 0; i < key->partnatts; i++)
                {
                    if (isnull[i])
                    {
                        range_partkey_has_null = true;
                        break;
                    }
                }
 
                /* NULLs belong in the DEFAULT partition */
                if (range_partkey_has_null)
                    break;
 
                if (partdesc->last_found_count >= PARTITION_CACHED_FIND_THRESHOLD)
                {
                    int         last_datum_offset = partdesc->last_found_datum_index;
                    Datum      *lastDatums = boundinfo->datums[last_datum_offset];
                    PartitionRangeDatumKind *kind = boundinfo->kind[last_datum_offset];
                    int32       cmpval;
 
                    /* check if the value is >= to the lower bound */
                    cmpval = partition_rbound_datum_cmp(key->partsupfunc,
                                                        key->partcollation,
                                                        lastDatums,
                                                        kind,
                                                        values,
                                                        key->partnatts);
 
                    /*
                     * If it's equal to the lower bound then no need to check
                     * the upper bound.
                     */
                    if (cmpval == 0)
                        return boundinfo->indexes[last_datum_offset + 1];
 
                    if (cmpval < 0 && last_datum_offset + 1 < boundinfo->ndatums)
                    {
                        /* check if the value is below the upper bound */
                        lastDatums = boundinfo->datums[last_datum_offset + 1];
                        kind = boundinfo->kind[last_datum_offset + 1];
                        cmpval = partition_rbound_datum_cmp(key->partsupfunc,
                                                            key->partcollation,
                                                            lastDatums,
                                                            kind,
                                                            values,
                                                            key->partnatts);
 
                        if (cmpval > 0)
                            return boundinfo->indexes[last_datum_offset + 1];
                    }
                    /* fall-through and do a manual lookup */
                }
 
                bound_offset = partition_range_datum_bsearch(key->partsupfunc,
                                                             key->partcollation,
                                                             boundinfo,
                                                             key->partnatts,
                                                             values,
                                                             &equal);
 
                /*
                 * The bound at bound_offset is less than or equal to the
                 * tuple value, so the bound at offset+1 is the upper bound of
                 * the partition we're looking for, if there actually exists
                 * one.
                 */
                part_index = boundinfo->indexes[bound_offset + 1];
            }
            break;
 
        default:
            elog(ERROR, "unexpected partition strategy: %d",
                 (int) key->strategy);
    }
 
    /*
     * part_index < 0 means we failed to find a partition of this parent. Use
     * the default partition, if there is one.
     */
    if (part_index < 0)
    {
        /*
         * No need to reset the cache fields here.  The next set of values
         * might end up belonging to the cached partition, so leaving the
         * cache alone improves the chances of a cache hit on the next lookup.
         */
        return boundinfo->default_index;
    }
 
    /* we should only make it here when the code above set bound_offset */
    Assert(bound_offset >= 0);
 
    /*
     * Attend to the cache fields.  If the bound_offset matches the last
     * cached bound offset then we've found the same partition as last time,
     * so bump the count by one.  If all goes well, we'll eventually reach
     * PARTITION_CACHED_FIND_THRESHOLD and try the cache path next time
     * around.  Otherwise, we'll reset the cache count back to 1 to mark that
     * we've found this partition for the first time.
     */
    if (bound_offset == partdesc->last_found_datum_index)
        partdesc->last_found_count++;
    else
    {
        partdesc->last_found_count = 1;
        partdesc->last_found_part_index = part_index;
        partdesc->last_found_datum_index = bound_offset;
    }
 
    return part_index;
}
 
/*
 * ExecBuildSlotPartitionKeyDescription
 *
 * This works very much like BuildIndexValueDescription() and is currently
 * used for building error messages when ExecFindPartition() fails to find
 * partition for a row.
 */
static char *
ExecBuildSlotPartitionKeyDescription(Relation rel,
                                     const Datum *values,
                                     const bool *isnull,
                                     int maxfieldlen)
{
    StringInfoData buf;
    PartitionKey key = RelationGetPartitionKey(rel);
    int         partnatts = get_partition_natts(key);
    int         i;
    Oid         relid = RelationGetRelid(rel);
    AclResult   aclresult;
 
    if (check_enable_rls(relid, InvalidOid, true) == RLS_ENABLED)
        return NULL;
 
    /* If the user has table-level access, just go build the description. */
    aclresult = pg_class_aclcheck(relid, GetUserId(), ACL_SELECT);
    if (aclresult != ACLCHECK_OK)
    {
        /*
         * Step through the columns of the partition key and make sure the
         * user has SELECT rights on all of them.
         */
        for (i = 0; i < partnatts; i++)
        {
            AttrNumber  attnum = get_partition_col_attnum(key, i);
 
            /*
             * If this partition key column is an expression, we return no
             * detail rather than try to figure out what column(s) the
             * expression includes and if the user has SELECT rights on them.
             */
            if (attnum == InvalidAttrNumber ||
                pg_attribute_aclcheck(relid, attnum, GetUserId(),
                                      ACL_SELECT) != ACLCHECK_OK)
                return NULL;
        }
    }
 
    initStringInfo(&buf);
    appendStringInfo(&buf, "(%s) = (",
                     pg_get_partkeydef_columns(relid, true));
 
    for (i = 0; i < partnatts; i++)
    {
        char       *val;
        int         vallen;
 
        if (isnull[i])
            val = "null";
        else
        {
            Oid         foutoid;
            bool        typisvarlena;
 
            getTypeOutputInfo(get_partition_col_typid(key, i),
                              &foutoid, &typisvarlena);
            val = OidOutputFunctionCall(foutoid, values[i]);
        }
 
        if (i > 0)
            appendStringInfoString(&buf, ", ");
 
        /* truncate if needed */
        vallen = strlen(val);
        if (vallen <= maxfieldlen)
            appendBinaryStringInfo(&buf, val, vallen);
        else
        {
            vallen = pg_mbcliplen(val, vallen, maxfieldlen);
            appendBinaryStringInfo(&buf, val, vallen);
            appendStringInfoString(&buf, "...");
        }
    }
 
    appendStringInfoChar(&buf, ')');
 
    return buf.data;
}
 
/*
 * adjust_partition_colnos
 *      Adjust the list of UPDATE target column numbers to account for
 *      attribute differences between the parent and the partition.
 *
 * Note: mustn't be called if no adjustment is required.
 */
static List *
adjust_partition_colnos(List *colnos, ResultRelInfo *leaf_part_rri)
{
    TupleConversionMap *map = ExecGetChildToRootMap(leaf_part_rri);
 
    Assert(map != NULL);
 
    return adjust_partition_colnos_using_map(colnos, map->attrMap);
}
 
/*
 * adjust_partition_colnos_using_map
 *      Like adjust_partition_colnos, but uses a caller-supplied map instead
 *      of assuming to map from the "root" result relation.
 *
 * Note: mustn't be called if no adjustment is required.
 */
static List *
adjust_partition_colnos_using_map(List *colnos, AttrMap *attrMap)
{
    List       *new_colnos = NIL;
    ListCell   *lc;
 
    Assert(attrMap != NULL);    /* else we shouldn't be here */
 
    foreach(lc, colnos)
    {
        AttrNumber  parentattrno = lfirst_int(lc);
 
        if (parentattrno <= 0 ||
            parentattrno > attrMap->maplen ||
            attrMap->attnums[parentattrno - 1] == 0)
            elog(ERROR, "unexpected attno %d in target column list",
                 parentattrno);
        new_colnos = lappend_int(new_colnos,
                                 attrMap->attnums[parentattrno - 1]);
    }
 
    return new_colnos;
}
 
/*-------------------------------------------------------------------------
 * Run-Time Partition Pruning Support.
 *
 * The following series of functions exist to support the removal of unneeded
 * subplans for queries against partitioned tables.  The supporting functions
 * here are designed to work with any plan type which supports an arbitrary
 * number of subplans, e.g. Append, MergeAppend.
 *
 * When pruning involves comparison of a partition key to a constant, it's
 * done by the planner.  However, if we have a comparison to a non-constant
 * but not volatile expression, that presents an opportunity for run-time
 * pruning by the executor, allowing irrelevant partitions to be skipped
 * dynamically.
 *
 * We must distinguish expressions containing PARAM_EXEC Params from
 * expressions that don't contain those.  Even though a PARAM_EXEC Param is
 * considered to be a stable expression, it can change value from one plan
 * node scan to the next during query execution.  Stable comparison
 * expressions that don't involve such Params allow partition pruning to be
 * done once during executor startup.  Expressions that do involve such Params
 * require us to prune separately for each scan of the parent plan node.
 *
 * Note that pruning away unneeded subplans during executor startup has the
 * added benefit of not having to initialize the unneeded subplans at all.
 *
 *
 * Functions:
 *
 * ExecDoInitialPruning:
 *      Perform runtime "initial" pruning, if necessary, to determine the set
 *      of child subnodes that need to be initialized during ExecInitNode() for
 *      all plan nodes that contain a PartitionPruneInfo.
 *
 * ExecInitPartitionExecPruning:
 *      Updates the PartitionPruneState found at given part_prune_index in
 *      EState.es_part_prune_states for use during "exec" pruning if required.
 *      Also returns the set of subplans to initialize that would be stored at
 *      part_prune_index in EState.es_part_prune_results by
 *      ExecDoInitialPruning().  Maps in PartitionPruneState are updated to
 *      account for initial pruning possibly having eliminated some of the
 *      subplans.
 *
 * ExecFindMatchingSubPlans:
 *      Returns indexes of matching subplans after evaluating the expressions
 *      that are safe to evaluate at a given point.  This function is first
 *      called during ExecDoInitialPruning() to find the initially matching
 *      subplans based on performing the initial pruning steps and then must be
 *      called again each time the value of a Param listed in
 *      PartitionPruneState's 'execparamids' changes.
 *-------------------------------------------------------------------------
 */
 
 
/*
 * ExecDoInitialPruning
 *      Perform runtime "initial" pruning, if necessary, to determine the set
 *      of child subnodes that need to be initialized during ExecInitNode() for
 *      plan nodes that support partition pruning.
 *
 * This function iterates over each PartitionPruneInfo entry in
 * estate->es_part_prune_infos. For each entry, it creates a PartitionPruneState
 * and adds it to es_part_prune_states.  ExecInitPartitionExecPruning() accesses
 * these states through their corresponding indexes in es_part_prune_states and
 * assign each state to the parent node's PlanState, from where it will be used
 * for "exec" pruning.
 *
 * If initial pruning steps exist for a PartitionPruneInfo entry, this function
 * executes those pruning steps and stores the result as a bitmapset of valid
 * child subplans, identifying which subplans should be initialized for
 * execution.  The results are saved in estate->es_part_prune_results.
 *
 * If no initial pruning is performed for a given PartitionPruneInfo, a NULL
 * entry  is still added to es_part_prune_results to maintain alignment with
 * es_part_prune_infos. This ensures that ExecInitPartitionExecPruning() can
 * use the same index to retrieve the pruning results.
 */
void
ExecDoInitialPruning(EState *estate)
{
    ListCell   *lc;
 
    foreach(lc, estate->es_part_prune_infos)
    {
        PartitionPruneInfo *pruneinfo = lfirst_node(PartitionPruneInfo, lc);
        PartitionPruneState *prunestate;
        Bitmapset  *validsubplans = NULL;
        Bitmapset  *all_leafpart_rtis = NULL;
        Bitmapset  *validsubplan_rtis = NULL;
 
        /* Create and save the PartitionPruneState. */
        prunestate = CreatePartitionPruneState(estate, pruneinfo,
                                               &all_leafpart_rtis);
        estate->es_part_prune_states = lappend(estate->es_part_prune_states,
                                               prunestate);
 
        /*
         * Perform initial pruning steps, if any, and save the result
         * bitmapset or NULL as described in the header comment.
         */
        if (prunestate->do_initial_prune)
            validsubplans = ExecFindMatchingSubPlans(prunestate, true,
                                                     &validsubplan_rtis);
        else
            validsubplan_rtis = all_leafpart_rtis;
 
        estate->es_unpruned_relids = bms_add_members(estate->es_unpruned_relids,
                                                     validsubplan_rtis);
        estate->es_part_prune_results = lappend(estate->es_part_prune_results,
                                                validsubplans);
    }
}
 
/*
 * ExecInitPartitionExecPruning
 *      Initialize the data structures needed for runtime "exec" partition
 *      pruning and return the result of initial pruning, if available.
 *
 * 'relids' identifies the relation to which both the parent plan and the
 * PartitionPruneInfo given by 'part_prune_index' belong.
 *
 * On return, *initially_valid_subplans is assigned the set of indexes of
 * child subplans that must be initialized along with the parent plan node.
 * Initial pruning would have been performed by ExecDoInitialPruning(), if
 * necessary, and the bitmapset of surviving subplans' indexes would have
 * been stored as the part_prune_index'th element of
 * EState.es_part_prune_results.
 *
 * If subplans were indeed pruned during initial pruning, the subplan_map
 * arrays in the returned PartitionPruneState are re-sequenced to exclude those
 * subplans, but only if the maps will be needed for subsequent execution
 * pruning passes.
 */
PartitionPruneState *
ExecInitPartitionExecPruning(PlanState *planstate,
                             int n_total_subplans,
                             int part_prune_index,
                             Bitmapset *relids,
                             Bitmapset **initially_valid_subplans)
{
    PartitionPruneState *prunestate;
    EState     *estate = planstate->state;
    PartitionPruneInfo *pruneinfo;
 
    /* Obtain the pruneinfo we need. */
    pruneinfo = list_nth_node(PartitionPruneInfo, estate->es_part_prune_infos,
                              part_prune_index);
 
    /* Its relids better match the plan node's or the planner messed up. */
    if (!bms_equal(relids, pruneinfo->relids))
        elog(ERROR, "wrong pruneinfo with relids=%s found at part_prune_index=%d contained in plan node with relids=%s",
             bmsToString(pruneinfo->relids), part_prune_index,
             bmsToString(relids));
 
    /*
     * The PartitionPruneState would have been created by
     * ExecDoInitialPruning() and stored as the part_prune_index'th element of
     * EState.es_part_prune_states.
     */
    prunestate = list_nth(estate->es_part_prune_states, part_prune_index);
    Assert(prunestate != NULL);
 
    /* Use the result of initial pruning done by ExecDoInitialPruning(). */
    if (prunestate->do_initial_prune)
        *initially_valid_subplans = list_nth_node(Bitmapset,
                                                  estate->es_part_prune_results,
                                                  part_prune_index);
    else
    {
        /* No pruning, so we'll need to initialize all subplans */
        Assert(n_total_subplans > 0);
        *initially_valid_subplans = bms_add_range(NULL, 0,
                                                  n_total_subplans - 1);
    }
 
    /*
     * The exec pruning state must also be initialized, if needed, before it
     * can be used for pruning during execution.
     *
     * This also re-sequences subplan indexes contained in prunestate to
     * account for any that were removed due to initial pruning; refer to the
     * condition in InitExecPartitionPruneContexts() that is used to determine
     * whether to do this.  If no exec pruning needs to be done, we would thus
     * leave the maps to be in an invalid state, but that's ok since that data
     * won't be consulted again (cf initial Assert in
     * ExecFindMatchingSubPlans).
     */
    if (prunestate->do_exec_prune)
        InitExecPartitionPruneContexts(prunestate, planstate,
                                       *initially_valid_subplans,
                                       n_total_subplans);
 
    return prunestate;
}
 
/*
 * CreatePartitionPruneState
 *      Build the data structure required for calling ExecFindMatchingSubPlans
 *
 * This includes PartitionPruneContexts (stored in each
 * PartitionedRelPruningData corresponding to a PartitionedRelPruneInfo),
 * which hold the ExprStates needed to evaluate pruning expressions, and
 * mapping arrays to convert partition indexes from the pruning logic
 * into subplan indexes in the parent plan node's list of child subplans.
 *
 * 'pruneinfo' is a PartitionPruneInfo as generated by
 * make_partition_pruneinfo.  Here we build a PartitionPruneState containing a
 * PartitionPruningData for each partitioning hierarchy (i.e., each sublist of
 * pruneinfo->prune_infos), each of which contains a PartitionedRelPruningData
 * for each PartitionedRelPruneInfo appearing in that sublist.  This two-level
 * system is needed to keep from confusing the different hierarchies when a
 * UNION ALL contains multiple partitioned tables as children.  The data
 * stored in each PartitionedRelPruningData can be re-used each time we
 * re-evaluate which partitions match the pruning steps provided in each
 * PartitionedRelPruneInfo.
 *
 * Note that only the PartitionPruneContexts for initial pruning are
 * initialized here. Those required for exec pruning are initialized later in
 * ExecInitPartitionExecPruning(), as they depend on the availability of the
 * parent plan node's PlanState.
 *
 * If initial pruning steps are to be skipped (e.g., during EXPLAIN
 * (GENERIC_PLAN)), *all_leafpart_rtis will be populated with the RT indexes of
 * all leaf partitions whose scanning subnode is included in the parent plan
 * node's list of child plans. The caller must add these RT indexes to
 * estate->es_unpruned_relids.
 */
static PartitionPruneState *
CreatePartitionPruneState(EState *estate, PartitionPruneInfo *pruneinfo,
                          Bitmapset **all_leafpart_rtis)
{
    PartitionPruneState *prunestate;
    int         n_part_hierarchies;
    ListCell   *lc;
    int         i;
 
    /*
     * Expression context that will be used by partkey_datum_from_expr() to
     * evaluate expressions for comparison against partition bounds.
     */
    ExprContext *econtext = CreateExprContext(estate);
 
    /* For data reading, executor always includes detached partitions */
    if (estate->es_partition_directory == NULL)
        estate->es_partition_directory =
            CreatePartitionDirectory(estate->es_query_cxt, false);
 
    n_part_hierarchies = list_length(pruneinfo->prune_infos);
    Assert(n_part_hierarchies > 0);
 
    /*
     * Allocate the data structure
     */
    prunestate = (PartitionPruneState *)
        palloc(offsetof(PartitionPruneState, partprunedata) +
               sizeof(PartitionPruningData *) * n_part_hierarchies);
 
    /* Save ExprContext for use during InitExecPartitionPruneContexts(). */
    prunestate->econtext = econtext;
    prunestate->execparamids = NULL;
    /* other_subplans can change at runtime, so we need our own copy */
    prunestate->other_subplans = bms_copy(pruneinfo->other_subplans);
    prunestate->do_initial_prune = false;   /* may be set below */
    prunestate->do_exec_prune = false;  /* may be set below */
    prunestate->num_partprunedata = n_part_hierarchies;
 
    /*
     * Create a short-term memory context which we'll use when making calls to
     * the partition pruning functions.  This avoids possible memory leaks,
     * since the pruning functions call comparison functions that aren't under
     * our control.
     */
    prunestate->prune_context =
        AllocSetContextCreate(CurrentMemoryContext,
                              "Partition Prune",
                              ALLOCSET_DEFAULT_SIZES);
 
    i = 0;
    foreach(lc, pruneinfo->prune_infos)
    {
        List       *partrelpruneinfos = lfirst_node(List, lc);
        int         npartrelpruneinfos = list_length(partrelpruneinfos);
        PartitionPruningData *prunedata;
        ListCell   *lc2;
        int         j;
 
        prunedata = (PartitionPruningData *)
            palloc(offsetof(PartitionPruningData, partrelprunedata) +
                   npartrelpruneinfos * sizeof(PartitionedRelPruningData));
        prunestate->partprunedata[i] = prunedata;
        prunedata->num_partrelprunedata = npartrelpruneinfos;
 
        j = 0;
        foreach(lc2, partrelpruneinfos)
        {
            PartitionedRelPruneInfo *pinfo = lfirst_node(PartitionedRelPruneInfo, lc2);
            PartitionedRelPruningData *pprune = &prunedata->partrelprunedata[j];
            Relation    partrel;
            PartitionDesc partdesc;
            PartitionKey partkey;
 
            /*
             * We can rely on the copies of the partitioned table's partition
             * key and partition descriptor appearing in its relcache entry,
             * because that entry will be held open and locked for the
             * duration of this executor run.
             */
            partrel = ExecGetRangeTableRelation(estate, pinfo->rtindex, false);
 
            /* Remember for InitExecPartitionPruneContexts(). */
            pprune->partrel = partrel;
 
            partkey = RelationGetPartitionKey(partrel);
            partdesc = PartitionDirectoryLookup(estate->es_partition_directory,
                                                partrel);
 
            /*
             * Initialize the subplan_map and subpart_map.
             *
             * The set of partitions that exist now might not be the same that
             * existed when the plan was made.  The normal case is that it is;
             * optimize for that case with a quick comparison, and just copy
             * the subplan_map and make subpart_map, leafpart_rti_map point to
             * the ones in PruneInfo.
             *
             * For the case where they aren't identical, we could have more
             * partitions on either side; or even exactly the same number of
             * them on both but the set of OIDs doesn't match fully.  Handle
             * this by creating new subplan_map and subpart_map arrays that
             * corresponds to the ones in the PruneInfo where the new
             * partition descriptor's OIDs match.  Any that don't match can be
             * set to -1, as if they were pruned.  By construction, both
             * arrays are in partition bounds order.
             */
            pprune->nparts = partdesc->nparts;
            pprune->subplan_map = palloc_array(int, partdesc->nparts);
 
            if (partdesc->nparts == pinfo->nparts &&
                memcmp(partdesc->oids, pinfo->relid_map,
                       sizeof(int) * partdesc->nparts) == 0)
            {
                pprune->subpart_map = pinfo->subpart_map;
                pprune->leafpart_rti_map = pinfo->leafpart_rti_map;
                memcpy(pprune->subplan_map, pinfo->subplan_map,
                       sizeof(int) * pinfo->nparts);
            }
            else
            {
                int         pd_idx = 0;
                int         pp_idx;
 
                /*
                 * When the partition arrays are not identical, there could be
                 * some new ones but it's also possible that one was removed;
                 * we cope with both situations by walking the arrays and
                 * discarding those that don't match.
                 *
                 * If the number of partitions on both sides match, it's still
                 * possible that one partition has been detached and another
                 * attached.  Cope with that by creating a map that skips any
                 * mismatches.
                 */
                pprune->subpart_map = palloc_array(int, partdesc->nparts);
                pprune->leafpart_rti_map = palloc_array(int, partdesc->nparts);
 
                for (pp_idx = 0; pp_idx < partdesc->nparts; pp_idx++)
                {
                    /* Skip any InvalidOid relid_map entries */
                    while (pd_idx < pinfo->nparts &&
                           !OidIsValid(pinfo->relid_map[pd_idx]))
                        pd_idx++;
 
            recheck:
                    if (pd_idx < pinfo->nparts &&
                        pinfo->relid_map[pd_idx] == partdesc->oids[pp_idx])
                    {
                        /* match... */
                        pprune->subplan_map[pp_idx] =
                            pinfo->subplan_map[pd_idx];
                        pprune->subpart_map[pp_idx] =
                            pinfo->subpart_map[pd_idx];
                        pprune->leafpart_rti_map[pp_idx] =
                            pinfo->leafpart_rti_map[pd_idx];
                        pd_idx++;
                        continue;
                    }
 
                    /*
                     * There isn't an exact match in the corresponding
                     * positions of both arrays.  Peek ahead in
                     * pinfo->relid_map to see if we have a match for the
                     * current partition in partdesc.  Normally if a match
                     * exists it's just one element ahead, and it means the
                     * planner saw one extra partition that we no longer see
                     * now (its concurrent detach finished just in between);
                     * so we skip that one by updating pd_idx to the new
                     * location and jumping above.  We can then continue to
                     * match the rest of the elements after skipping the OID
                     * with no match; no future matches are tried for the
                     * element that was skipped, because we know the arrays to
                     * be in the same order.
                     *
                     * If we don't see a match anywhere in the rest of the
                     * pinfo->relid_map array, that means we see an element
                     * now that the planner didn't see, so mark that one as
                     * pruned and move on.
                     */
                    for (int pd_idx2 = pd_idx + 1; pd_idx2 < pinfo->nparts; pd_idx2++)
                    {
                        if (pd_idx2 >= pinfo->nparts)
                            break;
                        if (pinfo->relid_map[pd_idx2] == partdesc->oids[pp_idx])
                        {
                            pd_idx = pd_idx2;
                            goto recheck;
                        }
                    }
 
                    pprune->subpart_map[pp_idx] = -1;
                    pprune->subplan_map[pp_idx] = -1;
                    pprune->leafpart_rti_map[pp_idx] = 0;
                }
            }
 
            /* present_parts is also subject to later modification */
            pprune->present_parts = bms_copy(pinfo->present_parts);
 
            /*
             * Only initial_context is initialized here.  exec_context is
             * initialized during ExecInitPartitionExecPruning() when the
             * parent plan's PlanState is available.
             *
             * Note that we must skip execution-time (both "init" and "exec")
             * partition pruning in EXPLAIN (GENERIC_PLAN), since parameter
             * values may be missing.
             */
            pprune->initial_pruning_steps = pinfo->initial_pruning_steps;
            if (pinfo->initial_pruning_steps &&
                !(econtext->ecxt_estate->es_top_eflags & EXEC_FLAG_EXPLAIN_GENERIC))
            {
                InitPartitionPruneContext(&pprune->initial_context,
                                          pprune->initial_pruning_steps,
                                          partdesc, partkey, NULL,
                                          econtext);
                /* Record whether initial pruning is needed at any level */
                prunestate->do_initial_prune = true;
            }
            pprune->exec_pruning_steps = pinfo->exec_pruning_steps;
            if (pinfo->exec_pruning_steps &&
                !(econtext->ecxt_estate->es_top_eflags & EXEC_FLAG_EXPLAIN_GENERIC))
            {
                /* Record whether exec pruning is needed at any level */
                prunestate->do_exec_prune = true;
            }
 
            /*
             * Accumulate the IDs of all PARAM_EXEC Params affecting the
             * partitioning decisions at this plan node.
             */
            prunestate->execparamids = bms_add_members(prunestate->execparamids,
                                                       pinfo->execparamids);
 
            /*
             * Return all leaf partition indexes if we're skipping pruning in
             * the EXPLAIN (GENERIC_PLAN) case.
             */
            if (pinfo->initial_pruning_steps && !prunestate->do_initial_prune)
            {
                int         part_index = -1;
 
                while ((part_index = bms_next_member(pprune->present_parts,
                                                     part_index)) >= 0)
                {
                    Index       rtindex = pprune->leafpart_rti_map[part_index];
 
                    if (rtindex)
                        *all_leafpart_rtis = bms_add_member(*all_leafpart_rtis,
                                                            rtindex);
                }
            }
 
            j++;
        }
        i++;
    }
 
    return prunestate;
}
 
/*
 * Initialize a PartitionPruneContext for the given list of pruning steps.
 */
static void
InitPartitionPruneContext(PartitionPruneContext *context,
                          List *pruning_steps,
                          PartitionDesc partdesc,
                          PartitionKey partkey,
                          PlanState *planstate,
                          ExprContext *econtext)
{
    int         n_steps;
    int         partnatts;
    ListCell   *lc;
 
    n_steps = list_length(pruning_steps);
 
    context->strategy = partkey->strategy;
    context->partnatts = partnatts = partkey->partnatts;
    context->nparts = partdesc->nparts;
    context->boundinfo = partdesc->boundinfo;
    context->partcollation = partkey->partcollation;
    context->partsupfunc = partkey->partsupfunc;
 
    /* We'll look up type-specific support functions as needed */
    context->stepcmpfuncs = palloc0_array(FmgrInfo, n_steps * partnatts);
 
    context->ppccontext = CurrentMemoryContext;
    context->planstate = planstate;
    context->exprcontext = econtext;
 
    /* Initialize expression state for each expression we need */
    context->exprstates = palloc0_array(ExprState *, n_steps * partnatts);
    foreach(lc, pruning_steps)
    {
        PartitionPruneStepOp *step = (PartitionPruneStepOp *) lfirst(lc);
        ListCell   *lc2 = list_head(step->exprs);
        int         keyno;
 
        /* not needed for other step kinds */
        if (!IsA(step, PartitionPruneStepOp))
            continue;
 
        Assert(list_length(step->exprs) <= partnatts);
 
        for (keyno = 0; keyno < partnatts; keyno++)
        {
            if (bms_is_member(keyno, step->nullkeys))
                continue;
 
            if (lc2 != NULL)
            {
                Expr       *expr = lfirst(lc2);
 
                /* not needed for Consts */
                if (!IsA(expr, Const))
                {
                    int         stateidx = PruneCxtStateIdx(partnatts,
                                                            step->step.step_id,
                                                            keyno);
 
                    /*
                     * When planstate is NULL, pruning_steps is known not to
                     * contain any expressions that depend on the parent plan.
                     * Information of any available EXTERN parameters must be
                     * passed explicitly in that case, which the caller must
                     * have made available via econtext.
                     */
                    if (planstate == NULL)
                        context->exprstates[stateidx] =
                            ExecInitExprWithParams(expr,
                                                   econtext->ecxt_param_list_info);
                    else
                        context->exprstates[stateidx] =
                            ExecInitExpr(expr, context->planstate);
                }
                lc2 = lnext(step->exprs, lc2);
            }
        }
    }
}
 
/*
 * InitExecPartitionPruneContexts
 *      Initialize exec pruning contexts deferred by CreatePartitionPruneState()
 *
 * This function finalizes exec pruning setup for a PartitionPruneState by
 * initializing contexts for pruning steps that require the parent plan's
 * PlanState. It iterates over PartitionPruningData entries and sets up the
 * necessary execution contexts for pruning during query execution.
 *
 * Also fix the mapping of partition indexes to subplan indexes contained in
 * prunestate by considering the new list of subplans that survived initial
 * pruning.
 *
 * Current values of the indexes present in PartitionPruneState count all the
 * subplans that would be present before initial pruning was done.  If initial
 * pruning got rid of some of the subplans, any subsequent pruning passes will
 * be looking at a different set of target subplans to choose from than those
 * in the pre-initial-pruning set, so the maps in PartitionPruneState
 * containing those indexes must be updated to reflect the new indexes of
 * subplans in the post-initial-pruning set.
 */
static void
InitExecPartitionPruneContexts(PartitionPruneState *prunestate,
                               PlanState *parent_plan,
                               Bitmapset *initially_valid_subplans,
                               int n_total_subplans)
{
    EState     *estate;
    int        *new_subplan_indexes = NULL;
    Bitmapset  *new_other_subplans;
    int         i;
    int         newidx;
    bool        fix_subplan_map = false;
 
    Assert(prunestate->do_exec_prune);
    Assert(parent_plan != NULL);
    estate = parent_plan->state;
 
    /*
     * No need to fix subplans maps if initial pruning didn't eliminate any
     * subplans.
     */
    if (bms_num_members(initially_valid_subplans) < n_total_subplans)
    {
        fix_subplan_map = true;
 
        /*
         * First we must build a temporary array which maps old subplan
         * indexes to new ones.  For convenience of initialization, we use
         * 1-based indexes in this array and leave pruned items as 0.
         */
        new_subplan_indexes = palloc0_array(int, n_total_subplans);
        newidx = 1;
        i = -1;
        while ((i = bms_next_member(initially_valid_subplans, i)) >= 0)
        {
            Assert(i < n_total_subplans);
            new_subplan_indexes[i] = newidx++;
        }
    }
 
    /*
     * Now we can update each PartitionedRelPruneInfo's subplan_map with new
     * subplan indexes.  We must also recompute its present_parts bitmap.
     */
    for (i = 0; i < prunestate->num_partprunedata; i++)
    {
        PartitionPruningData *prunedata = prunestate->partprunedata[i];
        int         j;
 
        /*
         * Within each hierarchy, we perform this loop in back-to-front order
         * so that we determine present_parts for the lowest-level partitioned
         * tables first.  This way we can tell whether a sub-partitioned
         * table's partitions were entirely pruned so we can exclude it from
         * the current level's present_parts.
         */
        for (j = prunedata->num_partrelprunedata - 1; j >= 0; j--)
        {
            PartitionedRelPruningData *pprune = &prunedata->partrelprunedata[j];
            int         nparts = pprune->nparts;
            int         k;
 
            /* Initialize PartitionPruneContext for exec pruning, if needed. */
            if (pprune->exec_pruning_steps != NIL)
            {
                PartitionKey partkey;
                PartitionDesc partdesc;
 
                /*
                 * See the comment in CreatePartitionPruneState() regarding
                 * the usage of partdesc and partkey.
                 */
                partkey = RelationGetPartitionKey(pprune->partrel);
                partdesc = PartitionDirectoryLookup(estate->es_partition_directory,
                                                    pprune->partrel);
 
                InitPartitionPruneContext(&pprune->exec_context,
                                          pprune->exec_pruning_steps,
                                          partdesc, partkey, parent_plan,
                                          prunestate->econtext);
            }
 
            if (!fix_subplan_map)
                continue;
 
            /* We just rebuild present_parts from scratch */
            bms_free(pprune->present_parts);
            pprune->present_parts = NULL;
 
            for (k = 0; k < nparts; k++)
            {
                int         oldidx = pprune->subplan_map[k];
                int         subidx;
 
                /*
                 * If this partition existed as a subplan then change the old
                 * subplan index to the new subplan index.  The new index may
                 * become -1 if the partition was pruned above, or it may just
                 * come earlier in the subplan list due to some subplans being
                 * removed earlier in the list.  If it's a subpartition, add
                 * it to present_parts unless it's entirely pruned.
                 */
                if (oldidx >= 0)
                {
                    Assert(oldidx < n_total_subplans);
                    pprune->subplan_map[k] = new_subplan_indexes[oldidx] - 1;
 
                    if (new_subplan_indexes[oldidx] > 0)
                        pprune->present_parts =
                            bms_add_member(pprune->present_parts, k);
                }
                else if ((subidx = pprune->subpart_map[k]) >= 0)
                {
                    PartitionedRelPruningData *subprune;
 
                    subprune = &prunedata->partrelprunedata[subidx];
 
                    if (!bms_is_empty(subprune->present_parts))
                        pprune->present_parts =
                            bms_add_member(pprune->present_parts, k);
                }
            }
        }
    }
 
    /*
     * If we fixed subplan maps, we must also recompute the other_subplans
     * set, since indexes in it may change.
     */
    if (fix_subplan_map)
    {
        new_other_subplans = NULL;
        i = -1;
        while ((i = bms_next_member(prunestate->other_subplans, i)) >= 0)
            new_other_subplans = bms_add_member(new_other_subplans,
                                                new_subplan_indexes[i] - 1);
 
        bms_free(prunestate->other_subplans);
        prunestate->other_subplans = new_other_subplans;
 
        pfree(new_subplan_indexes);
    }
}
 
/*
 * ExecFindMatchingSubPlans
 *      Determine which subplans match the pruning steps detailed in
 *      'prunestate' for the current comparison expression values.
 *
 * Pass initial_prune if PARAM_EXEC Params cannot yet be evaluated.  This
 * differentiates the initial executor-time pruning step from later
 * runtime pruning.
 *
 * The caller must pass a non-NULL validsubplan_rtis during initial pruning
 * to collect the RT indexes of leaf partitions whose subnodes will be
 * executed.  These RT indexes are later added to EState.es_unpruned_relids.
 */
Bitmapset *
ExecFindMatchingSubPlans(PartitionPruneState *prunestate,
                         bool initial_prune,
                         Bitmapset **validsubplan_rtis)
{
    Bitmapset  *result = NULL;
    MemoryContext oldcontext;
    int         i;
 
    /*
     * Either we're here on the initial prune done during pruning
     * initialization, or we're at a point where PARAM_EXEC Params can be
     * evaluated *and* there are steps in which to do so.
     */
    Assert(initial_prune || prunestate->do_exec_prune);
    Assert(validsubplan_rtis != NULL || !initial_prune);
 
    /*
     * Switch to a temp context to avoid leaking memory in the executor's
     * query-lifespan memory context.
     */
    oldcontext = MemoryContextSwitchTo(prunestate->prune_context);
 
    /*
     * For each hierarchy, do the pruning tests, and add nondeletable
     * subplans' indexes to "result".
     */
    for (i = 0; i < prunestate->num_partprunedata; i++)
    {
        PartitionPruningData *prunedata = prunestate->partprunedata[i];
        PartitionedRelPruningData *pprune;
 
        /*
         * We pass the zeroth item, belonging to the root table of the
         * hierarchy, and find_matching_subplans_recurse() takes care of
         * recursing to other (lower-level) parents as needed.
         */
        pprune = &prunedata->partrelprunedata[0];
        find_matching_subplans_recurse(prunedata, pprune, initial_prune,
                                       &result, validsubplan_rtis);
 
        /*
         * Expression eval may have used space in ExprContext too. Avoid
         * accessing exec_context during initial pruning, as it is not valid
         * at that stage.
         */
        if (!initial_prune && pprune->exec_pruning_steps)
            ResetExprContext(pprune->exec_context.exprcontext);
    }
 
    /* Add in any subplans that partition pruning didn't account for */
    result = bms_add_members(result, prunestate->other_subplans);
 
    MemoryContextSwitchTo(oldcontext);
 
    /* Copy result out of the temp context before we reset it */
    result = bms_copy(result);
    if (validsubplan_rtis)
        *validsubplan_rtis = bms_copy(*validsubplan_rtis);
 
    MemoryContextReset(prunestate->prune_context);
 
    return result;
}
 
/*
 * find_matching_subplans_recurse
 *      Recursive worker function for ExecFindMatchingSubPlans
 *
 * Adds valid (non-prunable) subplan IDs to *validsubplans. If
 * *validsubplan_rtis is non-NULL, it also adds the RT indexes of their
 * corresponding partitions, but only if they are leaf partitions.
 */
static void
find_matching_subplans_recurse(PartitionPruningData *prunedata,
                               PartitionedRelPruningData *pprune,
                               bool initial_prune,
                               Bitmapset **validsubplans,
                               Bitmapset **validsubplan_rtis)
{
    Bitmapset  *partset;
    int         i;
 
    /* Guard against stack overflow due to overly deep partition hierarchy. */
    check_stack_depth();
 
    /*
     * Prune as appropriate, if we have pruning steps matching the current
     * execution context.  Otherwise just include all partitions at this
     * level.
     */
    if (initial_prune && pprune->initial_pruning_steps)
        partset = get_matching_partitions(&pprune->initial_context,
                                          pprune->initial_pruning_steps);
    else if (!initial_prune && pprune->exec_pruning_steps)
        partset = get_matching_partitions(&pprune->exec_context,
                                          pprune->exec_pruning_steps);
    else
        partset = pprune->present_parts;
 
    /* Translate partset into subplan indexes */
    i = -1;
    while ((i = bms_next_member(partset, i)) >= 0)
    {
        if (pprune->subplan_map[i] >= 0)
        {
            *validsubplans = bms_add_member(*validsubplans,
                                            pprune->subplan_map[i]);
 
            /*
             * Only report leaf partitions. Non-leaf partitions may appear
             * here when they use an unflattened Append or MergeAppend.
             */
            if (validsubplan_rtis && pprune->leafpart_rti_map[i])
                *validsubplan_rtis = bms_add_member(*validsubplan_rtis,
                                                    pprune->leafpart_rti_map[i]);
        }
        else
        {
            int         partidx = pprune->subpart_map[i];
 
            if (partidx >= 0)
                find_matching_subplans_recurse(prunedata,
                                               &prunedata->partrelprunedata[partidx],
                                               initial_prune, validsubplans,
                                               validsubplan_rtis);
            else
            {
                /*
                 * We get here if the planner already pruned all the sub-
                 * partitions for this partition.  Silently ignore this
                 * partition in this case.  The end result is the same: we
                 * would have pruned all partitions just the same, but we
                 * don't have any pruning steps to execute to verify this.
                 */
            }
        }
    }
}