sortsupport.c File Reference

#include "postgres.h"
#include "access/gist.h"
#include "access/nbtree.h"
#include "catalog/pg_am.h"
#include "fmgr.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/sortsupport.h"

Include dependency graph for sortsupport.c:

Go to the source code of this file.

Data Structures
struct	SortShimExtra

Macros
#define	SizeForSortShimExtra(nargs)   (offsetof(SortShimExtra, fcinfo) + SizeForFunctionCallInfo(nargs))

Functions
static int	comparison_shim (Datum x, Datum y, SortSupport ssup)
void	PrepareSortSupportComparisonShim (Oid cmpFunc, SortSupport ssup)
static void	FinishSortSupportFunction (Oid opfamily, Oid opcintype, SortSupport ssup)
void	PrepareSortSupportFromOrderingOp (Oid orderingOp, SortSupport ssup)
void	PrepareSortSupportFromIndexRel (Relation indexRel, int16 strategy, SortSupport ssup)
void	PrepareSortSupportFromGistIndexRel (Relation indexRel, SortSupport ssup)

Macro Definition Documentation

SizeForSortShimExtra

#define SizeForSortShimExtra

(

nargs

)

(offsetof(SortShimExtra, fcinfo) + SizeForFunctionCallInfo(nargs))

Definition at line 34 of file sortsupport.c.

Function Documentation

comparison_shim()

static int comparison_shim ( Datum  x, Datum  y, SortSupport  ssup  )

static

Definition at line 44 of file sortsupport.c.

{
    SortShimExtra *extra = (SortShimExtra *) ssup->ssup_extra;
    Datum       result;
 
    extra->fcinfo.args[0].value = x;
    extra->fcinfo.args[1].value = y;
 
    /* just for paranoia's sake, we reset isnull each time */
    extra->fcinfo.isnull = false;
 
    result = FunctionCallInvoke(&extra->fcinfo);
 
    /* Check for null result, since caller is clearly not expecting one */
    if (extra->fcinfo.isnull)
        elog(ERROR, "function %u returned NULL", extra->flinfo.fn_oid);
 
    return result;
}

References FunctionCallInfoBaseData::args, elog(), ERROR, SortShimExtra::fcinfo, SortShimExtra::flinfo, FmgrInfo::fn_oid, FunctionCallInvoke, FunctionCallInfoBaseData::isnull, SortSupportData::ssup_extra, NullableDatum::value, x, and y.

Referenced by PrepareSortSupportComparisonShim().

FinishSortSupportFunction()

static void FinishSortSupportFunction ( Oid  opfamily, Oid  opcintype, SortSupport  ssup  )

static

Definition at line 95 of file sortsupport.c.

{
    Oid         sortSupportFunction;
 
    /* Look for a sort support function */
    sortSupportFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
                                            BTSORTSUPPORT_PROC);
    if (OidIsValid(sortSupportFunction))
    {
        /*
         * The sort support function can provide a comparator, but it can also
         * choose not to so (e.g. based on the selected collation).
         */
        OidFunctionCall1(sortSupportFunction, PointerGetDatum(ssup));
    }
 
    if (ssup->comparator == NULL)
    {
        Oid         sortFunction;
 
        sortFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
                                         BTORDER_PROC);
 
        if (!OidIsValid(sortFunction))
            elog(ERROR, "missing support function %d(%u,%u) in opfamily %u",
                 BTORDER_PROC, opcintype, opcintype, opfamily);
 
        /* We'll use a shim to call the old-style btree comparator */
        PrepareSortSupportComparisonShim(sortFunction, ssup);
    }
}

References BTORDER_PROC, BTSORTSUPPORT_PROC, SortSupportData::comparator, elog(), ERROR, get_opfamily_proc(), OidFunctionCall1, OidIsValid, PointerGetDatum(), and PrepareSortSupportComparisonShim().

Referenced by PrepareSortSupportFromIndexRel(), and PrepareSortSupportFromOrderingOp().

PrepareSortSupportComparisonShim()

void PrepareSortSupportComparisonShim	(	Oid	cmpFunc,
		SortSupport	ssup
	)

Definition at line 69 of file sortsupport.c.

{
    SortShimExtra *extra;
 
    extra = (SortShimExtra *) MemoryContextAlloc(ssup->ssup_cxt,
                                                 SizeForSortShimExtra(2));
 
    /* Lookup the comparison function */
    fmgr_info_cxt(cmpFunc, &extra->flinfo, ssup->ssup_cxt);
 
    /* We can initialize the callinfo just once and re-use it */
    InitFunctionCallInfoData(extra->fcinfo, &extra->flinfo, 2,
                             ssup->ssup_collation, NULL, NULL);
    extra->fcinfo.args[0].isnull = false;
    extra->fcinfo.args[1].isnull = false;
 
    ssup->ssup_extra = extra;
    ssup->comparator = comparison_shim;
}

References FunctionCallInfoBaseData::args, SortSupportData::comparator, comparison_shim(), SortShimExtra::fcinfo, SortShimExtra::flinfo, fmgr_info_cxt(), InitFunctionCallInfoData, NullableDatum::isnull, MemoryContextAlloc(), SizeForSortShimExtra, SortSupportData::ssup_collation, SortSupportData::ssup_cxt, and SortSupportData::ssup_extra.

Referenced by FinishSortSupportFunction(), and MJExamineQuals().

PrepareSortSupportFromGistIndexRel()

void PrepareSortSupportFromGistIndexRel	(	Relation	indexRel,
		SortSupport	ssup
	)

Definition at line 189 of file sortsupport.c.

{
    Oid         opfamily = indexRel->rd_opfamily[ssup->ssup_attno - 1];
    Oid         opcintype = indexRel->rd_opcintype[ssup->ssup_attno - 1];
    Oid         sortSupportFunction;
 
    Assert(ssup->comparator == NULL);
 
    if (indexRel->rd_rel->relam != GIST_AM_OID)
        elog(ERROR, "unexpected non-gist AM: %u", indexRel->rd_rel->relam);
    ssup->ssup_reverse = false;
 
    /*
     * Look up the sort support function. This is simpler than for B-tree
     * indexes because we don't support the old-style btree comparators.
     */
    sortSupportFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
                                            GIST_SORTSUPPORT_PROC);
    if (!OidIsValid(sortSupportFunction))
        elog(ERROR, "missing support function %d(%u,%u) in opfamily %u",
             GIST_SORTSUPPORT_PROC, opcintype, opcintype, opfamily);
    OidFunctionCall1(sortSupportFunction, PointerGetDatum(ssup));
}

References Assert(), SortSupportData::comparator, elog(), ERROR, get_opfamily_proc(), GIST_SORTSUPPORT_PROC, OidFunctionCall1, OidIsValid, PointerGetDatum(), RelationData::rd_opcintype, RelationData::rd_opfamily, RelationData::rd_rel, SortSupportData::ssup_attno, and SortSupportData::ssup_reverse.

Referenced by tuplesort_begin_index_gist().

PrepareSortSupportFromIndexRel()

void PrepareSortSupportFromIndexRel	(	Relation	indexRel,
		int16	strategy,
		SortSupport	ssup
	)

Definition at line 162 of file sortsupport.c.

{
    Oid         opfamily = indexRel->rd_opfamily[ssup->ssup_attno - 1];
    Oid         opcintype = indexRel->rd_opcintype[ssup->ssup_attno - 1];
 
    Assert(ssup->comparator == NULL);
 
    if (indexRel->rd_rel->relam != BTREE_AM_OID)
        elog(ERROR, "unexpected non-btree AM: %u", indexRel->rd_rel->relam);
    if (strategy != BTGreaterStrategyNumber &&
        strategy != BTLessStrategyNumber)
        elog(ERROR, "unexpected sort support strategy: %d", strategy);
    ssup->ssup_reverse = (strategy == BTGreaterStrategyNumber);
 
    FinishSortSupportFunction(opfamily, opcintype, ssup);
}

References Assert(), BTGreaterStrategyNumber, BTLessStrategyNumber, SortSupportData::comparator, elog(), ERROR, FinishSortSupportFunction(), RelationData::rd_opcintype, RelationData::rd_opfamily, RelationData::rd_rel, SortSupportData::ssup_attno, and SortSupportData::ssup_reverse.

Referenced by _bt_load(), tuplesort_begin_cluster(), and tuplesort_begin_index_btree().

PrepareSortSupportFromOrderingOp()

void PrepareSortSupportFromOrderingOp	(	Oid	orderingOp,
		SortSupport	ssup
	)

Definition at line 135 of file sortsupport.c.

{
    Oid         opfamily;
    Oid         opcintype;
    int16       strategy;
 
    Assert(ssup->comparator == NULL);
 
    /* Find the operator in pg_amop */
    if (!get_ordering_op_properties(orderingOp, &opfamily, &opcintype,
                                    &strategy))
        elog(ERROR, "operator %u is not a valid ordering operator",
             orderingOp);
    ssup->ssup_reverse = (strategy == BTGreaterStrategyNumber);
 
    FinishSortSupportFunction(opfamily, opcintype, ssup);
}

References Assert(), BTGreaterStrategyNumber, SortSupportData::comparator, elog(), ERROR, FinishSortSupportFunction(), get_ordering_op_properties(), and SortSupportData::ssup_reverse.

Referenced by compute_scalar_stats(), ExecInitGatherMerge(), ExecInitIndexScan(), ExecInitMergeAppend(), multi_sort_add_dimension(), statext_mcv_serialize(), tuplesort_begin_datum(), and tuplesort_begin_heap().