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Replace ALTER TABLE ... SET STATISTICS DISTINCT with a more general mechanism.

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Attributes can now have options, just as relations and tablespaces do, and
the reloptions code is used to parse, validate, and store them.  For
simplicity and because these options are not performance critical, we store
them in a separate cache rather than the main relcache.

Thanks to Alex Hunsaker for the review.
This commit is contained in:
Robert Haas
2010-01-22 16:40:19 +00:00
parent 9ca0989037
commit 76a47c0e74
19 changed files with 267 additions and 223 deletions
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34
src/backend/commands/analyze.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.147 2010/01/02 16:57:36 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.148 2010/01/22 16:40:18 rhaas Exp $
*
*-------------------------------------------------------------------------
*/
@ -39,6 +39,7 @@
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/attoptcache.h"
#include "utils/datum.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
@ -493,6 +494,8 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
for (i = 0; i < attr_cnt; i++)
{
VacAttrStats *stats = vacattrstats[i];
AttributeOpts *aopt =
get_attribute_options(onerel->rd_id, stats->attr->attnum);
stats->rows = rows;
stats->tupDesc = onerel->rd_att;
@ -501,9 +504,17 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
numrows,
totalrows);
/* If attdistinct is set, override with that value */
if (stats->attr->attdistinct != 0)
stats->stadistinct = stats->attr->attdistinct;
/*
* If the appropriate flavor of the n_distinct option is
* specified, override with the corresponding value.
*/
if (aopt != NULL)
{
float8 n_distinct =
inh ? aopt->n_distinct_inherited : aopt->n_distinct;
if (n_distinct != 0.0)
stats->stadistinct = n_distinct;
}
MemoryContextResetAndDeleteChildren(col_context);
}
@ -751,6 +762,9 @@ compute_index_stats(Relation onerel, double totalrows,
for (i = 0; i < attr_cnt; i++)
{
VacAttrStats *stats = thisdata->vacattrstats[i];
AttributeOpts *aopt =
get_attribute_options(stats->attr->attrelid,
stats->attr->attnum);
stats->exprvals = exprvals + i;
stats->exprnulls = exprnulls + i;
@ -759,9 +773,15 @@ compute_index_stats(Relation onerel, double totalrows,
ind_fetch_func,
numindexrows,
totalindexrows);
/* If attdistinct is set, override with that value */
if (stats->attr->attdistinct != 0)
stats->stadistinct = stats->attr->attdistinct;
/*
* If the n_distinct option is specified, it overrides the
* above computation. For indices, we always use just
* n_distinct, not n_distinct_inherited.
*/
if (aopt != NULL && aopt->n_distinct != 0.0)
stats->stadistinct = aopt->n_distinct;
MemoryContextResetAndDeleteChildren(col_context);
}
}