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Increase the default value of default_statistics_target from 10 to 100,

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and its maximum value from 1000 to 10000.  ALTER TABLE SET STATISTICS
similarly now allows a value up to 10000.  Per discussion.
This commit is contained in:
Tom Lane
2008-12-13 19:13:44 +00:00
parent b69bde7749
commit 65e3ea7641
9 changed files with 27 additions and 27 deletions
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8
src/backend/commands/analyze.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.128 2008/11/10 00:49:37 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.129 2008/12/13 19:13:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -67,7 +67,7 @@ typedef struct AnlIndexData
/* Default statistics target (GUC parameter) */
int default_statistics_target = 10;
int default_statistics_target = 100;
/* A few variables that don't seem worth passing around as parameters */
static int elevel = -1;
@@ -1531,10 +1531,10 @@ std_typanalyze(VacAttrStats *stats)
* error in bin size f, and error probability gamma, the minimum
* random sample size is
* r = 4 * k * ln(2*n/gamma) / f^2
* Taking f = 0.5, gamma = 0.01, n = 1 million rows, we obtain
* Taking f = 0.5, gamma = 0.01, n = 10^6 rows, we obtain
* r = 305.82 * k
* Note that because of the log function, the dependence on n is
* quite weak; even at n = 1 billion, a 300*k sample gives <= 0.59
* quite weak; even at n = 10^12, a 300*k sample gives <= 0.66
* bin size error with probability 0.99. So there's no real need to
* scale for n, which is a good thing because we don't necessarily
* know it at this point.

6
src/backend/commands/tablecmds.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.272 2008/12/06 23:22:46 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.273 2008/12/13 19:13:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3942,9 +3942,9 @@ ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
errmsg("statistics target %d is too low",
newtarget)));
}
else if (newtarget > 1000)
else if (newtarget > 10000)
{
newtarget = 1000;
newtarget = 10000;
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("lowering statistics target to %d",