partitionfuncs.c File Reference

#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/partition.h"
#include "catalog/pg_class.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "utils/fmgrprotos.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"

Include dependency graph for partitionfuncs.c:

Go to the source code of this file.

Macros
#define	PG_PARTITION_TREE_COLS   4

Functions
static bool	check_rel_can_be_partition (Oid relid)
Datum	pg_partition_tree (PG_FUNCTION_ARGS)
Datum	pg_partition_root (PG_FUNCTION_ARGS)
Datum	pg_partition_ancestors (PG_FUNCTION_ARGS)

Macro Definition Documentation

PG_PARTITION_TREE_COLS

#define PG_PARTITION_TREE_COLS   4

Function Documentation

check_rel_can_be_partition()

static bool check_rel_can_be_partition ( Oid  relid )

static

Definition at line 35 of file partitionfuncs.c.

{
    char        relkind;
    bool        relispartition;
 
    /* Check if relation exists */
    if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(relid)))
        return false;
 
    relkind = get_rel_relkind(relid);
    relispartition = get_rel_relispartition(relid);
 
    /* Only allow relation types that can appear in partition trees. */
    if (!relispartition && !RELKIND_HAS_PARTITIONS(relkind))
        return false;
 
    return true;
}

References get_rel_relispartition(), get_rel_relkind(), ObjectIdGetDatum(), RELOID, and SearchSysCacheExists1.

Referenced by pg_partition_ancestors(), pg_partition_root(), and pg_partition_tree().

pg_partition_ancestors()

Datum pg_partition_ancestors

(

PG_FUNCTION_ARGS

)

Definition at line 202 of file partitionfuncs.c.

{
    Oid         relid = PG_GETARG_OID(0);
    FuncCallContext *funcctx;
    List       *ancestors;
 
    if (SRF_IS_FIRSTCALL())
    {
        MemoryContext oldcxt;
 
        funcctx = SRF_FIRSTCALL_INIT();
 
        if (!check_rel_can_be_partition(relid))
            SRF_RETURN_DONE(funcctx);
 
        oldcxt = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        ancestors = get_partition_ancestors(relid);
        ancestors = lcons_oid(relid, ancestors);
 
        /* The only state we need is the ancestors list */
        funcctx->user_fctx = (void *) ancestors;
 
        MemoryContextSwitchTo(oldcxt);
    }
 
    funcctx = SRF_PERCALL_SETUP();
    ancestors = (List *) funcctx->user_fctx;
 
    if (funcctx->call_cntr < list_length(ancestors))
    {
        Oid         resultrel = list_nth_oid(ancestors, funcctx->call_cntr);
 
        SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(resultrel));
    }
 
    SRF_RETURN_DONE(funcctx);
}

References FuncCallContext::call_cntr, check_rel_can_be_partition(), get_partition_ancestors(), if(), lcons_oid(), list_length(), list_nth_oid(), MemoryContextSwitchTo(), FuncCallContext::multi_call_memory_ctx, ObjectIdGetDatum(), PG_GETARG_OID, SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, and FuncCallContext::user_fctx.

pg_partition_root()

Datum pg_partition_root

(

PG_FUNCTION_ARGS

)

Definition at line 165 of file partitionfuncs.c.

{
    Oid         relid = PG_GETARG_OID(0);
    Oid         rootrelid;
    List       *ancestors;
 
    if (!check_rel_can_be_partition(relid))
        PG_RETURN_NULL();
 
    /* fetch the list of ancestors */
    ancestors = get_partition_ancestors(relid);
 
    /*
     * If the input relation is already the top-most parent, just return
     * itself.
     */
    if (ancestors == NIL)
        PG_RETURN_OID(relid);
 
    rootrelid = llast_oid(ancestors);
    list_free(ancestors);
 
    /*
     * "rootrelid" must contain a valid OID, given that the input relation is
     * a valid partition tree member as checked above.
     */
    Assert(OidIsValid(rootrelid));
    PG_RETURN_OID(rootrelid);
}

References Assert(), check_rel_can_be_partition(), get_partition_ancestors(), list_free(), llast_oid, NIL, OidIsValid, PG_GETARG_OID, PG_RETURN_NULL, and PG_RETURN_OID.

pg_partition_tree()

Datum pg_partition_tree

(

PG_FUNCTION_ARGS

)

Definition at line 63 of file partitionfuncs.c.

{
#define PG_PARTITION_TREE_COLS  4
    Oid         rootrelid = PG_GETARG_OID(0);
    FuncCallContext *funcctx;
    List       *partitions;
 
    /* stuff done only on the first call of the function */
    if (SRF_IS_FIRSTCALL())
    {
        MemoryContext oldcxt;
        TupleDesc   tupdesc;
 
        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();
 
        if (!check_rel_can_be_partition(rootrelid))
            SRF_RETURN_DONE(funcctx);
 
        /* switch to memory context appropriate for multiple function calls */
        oldcxt = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        /*
         * Find all members of inheritance set.  We only need AccessShareLock
         * on the children for the partition information lookup.
         */
        partitions = find_all_inheritors(rootrelid, AccessShareLock, NULL);
 
        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
            elog(ERROR, "return type must be a row type");
        funcctx->tuple_desc = tupdesc;
 
        /* The only state we need is the partition list */
        funcctx->user_fctx = (void *) partitions;
 
        MemoryContextSwitchTo(oldcxt);
    }
 
    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();
    partitions = (List *) funcctx->user_fctx;
 
    if (funcctx->call_cntr < list_length(partitions))
    {
        Datum       result;
        Datum       values[PG_PARTITION_TREE_COLS] = {0};
        bool        nulls[PG_PARTITION_TREE_COLS] = {0};
        HeapTuple   tuple;
        Oid         parentid = InvalidOid;
        Oid         relid = list_nth_oid(partitions, funcctx->call_cntr);
        char        relkind = get_rel_relkind(relid);
        int         level = 0;
        List       *ancestors = get_partition_ancestors(relid);
        ListCell   *lc;
 
        /*
         * Form tuple with appropriate data.
         */
 
        /* relid */
        values[0] = ObjectIdGetDatum(relid);
 
        /* parentid */
        if (ancestors != NIL)
            parentid = linitial_oid(ancestors);
        if (OidIsValid(parentid))
            values[1] = ObjectIdGetDatum(parentid);
        else
            nulls[1] = true;
 
        /* isleaf */
        values[2] = BoolGetDatum(!RELKIND_HAS_PARTITIONS(relkind));
 
        /* level */
        if (relid != rootrelid)
        {
            foreach(lc, ancestors)
            {
                level++;
                if (lfirst_oid(lc) == rootrelid)
                    break;
            }
        }
        values[3] = Int32GetDatum(level);
 
        tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
        result = HeapTupleGetDatum(tuple);
        SRF_RETURN_NEXT(funcctx, result);
    }
 
    /* done when there are no more elements left */
    SRF_RETURN_DONE(funcctx);
}

References AccessShareLock, BoolGetDatum(), FuncCallContext::call_cntr, check_rel_can_be_partition(), elog(), ERROR, find_all_inheritors(), get_call_result_type(), get_partition_ancestors(), get_rel_relkind(), heap_form_tuple(), HeapTupleGetDatum(), if(), Int32GetDatum(), InvalidOid, lfirst_oid, linitial_oid, list_length(), list_nth_oid(), MemoryContextSwitchTo(), FuncCallContext::multi_call_memory_ctx, NIL, ObjectIdGetDatum(), OidIsValid, partitions, PG_GETARG_OID, PG_PARTITION_TREE_COLS, SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, FuncCallContext::tuple_desc, TYPEFUNC_COMPOSITE, FuncCallContext::user_fctx, and values.