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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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50
src/backend/access/common/reloptions.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/common/reloptions.c,v 1.31 2010/01/05 21:53:58 rhaas Exp $
* $PostgreSQL: pgsql/src/backend/access/common/reloptions.c,v 1.32 2010/01/22 16:40:18 rhaas Exp $
*
*-------------------------------------------------------------------------
*/
@ -24,6 +24,7 @@
#include "commands/tablespace.h"
#include "nodes/makefuncs.h"
#include "utils/array.h"
#include "utils/attoptcache.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/memutils.h"
@ -196,6 +197,22 @@ static relopt_real realRelOpts[] =
},
-1, 0.0, DBL_MAX
},
{
{
"n_distinct",
"Sets the planner's estimate of the number of distinct values appearing in a column (excluding child relations).",
RELOPT_KIND_ATTRIBUTE
},
0, -1.0, DBL_MAX
},
{
{
"n_distinct_inherited",
"Sets the planner's estimate of the number of distinct values appearing in a column (including child relations).",
RELOPT_KIND_ATTRIBUTE
},
0, -1.0, DBL_MAX
},
/* list terminator */
{{NULL}}
};
@ -1186,6 +1203,37 @@ index_reloptions(RegProcedure amoptions, Datum reloptions, bool validate)
return DatumGetByteaP(result);
}
/*
* Option parser for attribute reloptions
*/
bytea *
attribute_reloptions(Datum reloptions, bool validate)
{
relopt_value *options;
AttributeOpts *aopts;
int numoptions;
static const relopt_parse_elt tab[] = {
{"n_distinct", RELOPT_TYPE_REAL, offsetof(AttributeOpts, n_distinct)},
{"n_distinct_inherited", RELOPT_TYPE_REAL, offsetof(AttributeOpts, n_distinct_inherited)}
};
options = parseRelOptions(reloptions, validate, RELOPT_KIND_ATTRIBUTE,
&numoptions);
/* if none set, we're done */
if (numoptions == 0)
return NULL;
aopts = allocateReloptStruct(sizeof(AttributeOpts), options, numoptions);
fillRelOptions((void *) aopts, sizeof(AttributeOpts), options, numoptions,
validate, tab, lengthof(tab));
pfree(options);
return (bytea *) aopts;
}
/*
* Option parser for tablespace reloptions
*/