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Make use of qsort_arg in several places that were formerly using klugy

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static variables.  This avoids any risk of potential non-reentrancy,
and in particular offers a much cleaner workaround for the Intel compiler
bug that was affecting ginutil.c.
This commit is contained in:
Tom Lane
2006-10-05 17:57:40 +00:00
parent f2332ea1e9
commit e378f82e00
6 changed files with 77 additions and 88 deletions
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45
src/backend/commands/analyze.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.99 2006/10/04 00:29:50 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.100 2006/10/05 17:57:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1294,11 +1294,12 @@ typedef struct
int first; /* values[] index of first occurrence */
} ScalarMCVItem;
/* context information for compare_scalars() */
static FmgrInfo *datumCmpFn;
static SortFunctionKind datumCmpFnKind;
static int *datumCmpTupnoLink;
typedef struct
{
FmgrInfo *cmpFn;
SortFunctionKind cmpFnKind;
int *tupnoLink;
} CompareScalarsContext;
static void compute_minimal_stats(VacAttrStatsP stats,
@ -1309,7 +1310,7 @@ static void compute_scalar_stats(VacAttrStatsP stats,
AnalyzeAttrFetchFunc fetchfunc,
int samplerows,
double totalrows);
static int compare_scalars(const void *a, const void *b);
static int compare_scalars(const void *a, const void *b, void *arg);
static int compare_mcvs(const void *a, const void *b);
@ -1828,13 +1829,14 @@ compute_scalar_stats(VacAttrStatsP stats,
num_hist,
dups_cnt;
int slot_idx = 0;
CompareScalarsContext cxt;
/* Sort the collected values */
datumCmpFn = &f_cmpfn;
datumCmpFnKind = cmpFnKind;
datumCmpTupnoLink = tupnoLink;
qsort((void *) values, values_cnt,
sizeof(ScalarItem), compare_scalars);
cxt.cmpFn = &f_cmpfn;
cxt.cmpFnKind = cmpFnKind;
cxt.tupnoLink = tupnoLink;
qsort_arg((void *) values, values_cnt, sizeof(ScalarItem),
compare_scalars, (void *) &cxt);
/*
* Now scan the values in order, find the most common ones, and also
@ -2183,35 +2185,36 @@ compute_scalar_stats(VacAttrStatsP stats,
}
/*
* qsort comparator for sorting ScalarItems
* qsort_arg comparator for sorting ScalarItems
*
* Aside from sorting the items, we update the datumCmpTupnoLink[] array
* Aside from sorting the items, we update the tupnoLink[] array
* whenever two ScalarItems are found to contain equal datums. The array
* is indexed by tupno; for each ScalarItem, it contains the highest
* tupno that that item's datum has been found to be equal to. This allows
* us to avoid additional comparisons in compute_scalar_stats().
*/
static int
compare_scalars(const void *a, const void *b)
compare_scalars(const void *a, const void *b, void *arg)
{
Datum da = ((ScalarItem *) a)->value;
int ta = ((ScalarItem *) a)->tupno;
Datum db = ((ScalarItem *) b)->value;
int tb = ((ScalarItem *) b)->tupno;
CompareScalarsContext *cxt = (CompareScalarsContext *) arg;
int32 compare;
compare = ApplySortFunction(datumCmpFn, datumCmpFnKind,
compare = ApplySortFunction(cxt->cmpFn, cxt->cmpFnKind,
da, false, db, false);
if (compare != 0)
return compare;
/*
* The two datums are equal, so update datumCmpTupnoLink[].
* The two datums are equal, so update cxt->tupnoLink[].
*/
if (datumCmpTupnoLink[ta] < tb)
datumCmpTupnoLink[ta] = tb;
if (datumCmpTupnoLink[tb] < ta)
datumCmpTupnoLink[tb] = ta;
if (cxt->tupnoLink[ta] < tb)
cxt->tupnoLink[ta] = tb;
if (cxt->tupnoLink[tb] < ta)
cxt->tupnoLink[tb] = ta;
/*
* For equal datums, sort by tupno