Add macro for maximum statistics target

petere · petere · commit 7a7f60aef8bf · 2023-07-03T07:18:57.000+02:00
The number of places where 10000 was hardcoded had grown a bit beyond the comfort level. Introduce a macro MAX_STATISTICS_TARGET instead. Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Discussion: https://www.postgresql.org/message-id/flat/d6069765-5971-04d3-c10d-e4f7b2e9c459%40eisentraut.org
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
@@ -619,9 +619,9 @@ AlterStatistics(AlterStatsStmt *stmt)
 				 errmsg("statistics target %d is too low",
 						newtarget)));
 	}
-	else if (newtarget > 10000)
+	else if (newtarget > MAX_STATISTICS_TARGET)
 	{
-		newtarget = 10000;
+		newtarget = MAX_STATISTICS_TARGET;
 		ereport(WARNING,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("lowering statistics target to %d",
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
@@ -61,6 +61,7 @@
 #include "commands/trigger.h"
 #include "commands/typecmds.h"
 #include "commands/user.h"
+#include "commands/vacuum.h"
 #include "executor/executor.h"
 #include "foreign/fdwapi.h"
 #include "foreign/foreign.h"
@@ -8180,9 +8181,9 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("statistics target %d is too low",
 						newtarget)));
 	}
-	else if (newtarget > 10000)
+	else if (newtarget > MAX_STATISTICS_TARGET)
 	{
-		newtarget = 10000;
+		newtarget = MAX_STATISTICS_TARGET;
 		ereport(WARNING,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("lowering statistics target to %d",
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
@@ -379,7 +379,7 @@ statext_compute_stattarget(int stattarget, int nattrs, VacAttrStats **stats)
 		stattarget = default_statistics_target;
 
 	/* As this point we should have a valid statistics target. */
-	Assert((stattarget >= 0) && (stattarget <= 10000));
+	Assert((stattarget >= 0) && (stattarget <= MAX_STATISTICS_TARGET));
 
 	return stattarget;
 }
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
@@ -2035,7 +2035,7 @@ struct config_int ConfigureNamesInt[] =
 						 "column-specific target set via ALTER TABLE SET STATISTICS.")
 		},
 		&default_statistics_target,
-		100, 1, 10000,
+		100, 1, MAX_STATISTICS_TARGET,
 		NULL, NULL, NULL
 	},
 	{
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
@@ -165,7 +165,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,
 	 * that no value has been explicitly set for this column, so ANALYZE
 	 * should use the default setting.
 	 *
-	 * int16 is sufficient because the max value is currently 10000.
+	 * int16 is sufficient for the current max value (MAX_STATISTICS_TARGET).
 	 */
 	int16		attstattarget BKI_DEFAULT(-1);
 
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
@@ -305,6 +305,13 @@ extern PGDLLIMPORT int vacuum_multixact_freeze_table_age;
 extern PGDLLIMPORT int vacuum_failsafe_age;
 extern PGDLLIMPORT int vacuum_multixact_failsafe_age;
 
+/*
+ * Maximum value for default_statistics_target and per-column statistics
+ * targets.  This is fairly arbitrary, mainly to prevent users from creating
+ * unreasonably large statistics that the system cannot handle well.
+ */
+#define MAX_STATISTICS_TARGET 10000
+
 /* Variables for cost-based parallel vacuum */
 extern PGDLLIMPORT pg_atomic_uint32 *VacuumSharedCostBalance;
 extern PGDLLIMPORT pg_atomic_uint32 *VacuumActiveNWorkers;
diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
@@ -66,8 +66,8 @@ typedef struct MVDependencies
 #define STATS_MCV_MAGIC			0xE1A651C2	/* marks serialized bytea */
 #define STATS_MCV_TYPE_BASIC	1	/* basic MCV list type */
 
-/* max items in MCV list (should be equal to max default_statistics_target) */
-#define STATS_MCVLIST_MAX_ITEMS        10000
+/* max items in MCV list */
+#define STATS_MCVLIST_MAX_ITEMS        MAX_STATISTICS_TARGET
 
 /*
  * Multivariate MCV (most-common value) lists

Original file line number	Diff line number	Diff line change
`@@ -619,9 +619,9 @@ AlterStatistics(AlterStatsStmt *stmt)`
`619`	`619`	`errmsg("statistics target %d is too low",`
`620`	`620`	`newtarget)));`
`621`	`621`	`}`
`622`		`- else if (newtarget > 10000)`
	`622`	`+ else if (newtarget > MAX_STATISTICS_TARGET)`
`623`	`623`	`{`
`624`		`- newtarget = 10000;`
	`624`	`+ newtarget = MAX_STATISTICS_TARGET;`
`625`	`625`	`ereport(WARNING,`
`626`	`626`	`(errcode(ERRCODE_INVALID_PARAMETER_VALUE),`
`627`	`627`	`errmsg("lowering statistics target to %d",`
Original file line number	Diff line number	Diff line change
`@@ -379,7 +379,7 @@ statext_compute_stattarget(int stattarget, int nattrs, VacAttrStats **stats)`
`379`	`379`	`stattarget = default_statistics_target;`
`380`	`380`
`381`	`381`	`/* As this point we should have a valid statistics target. */`
`382`		`- Assert((stattarget >= 0) && (stattarget <= 10000));`
	`382`	`+ Assert((stattarget >= 0) && (stattarget <= MAX_STATISTICS_TARGET));`
`383`	`383`
`384`	`384`	`return stattarget;`
`385`	`385`	`}`
Original file line number	Diff line number	Diff line change
`@@ -2035,7 +2035,7 @@ struct config_int ConfigureNamesInt[] =`
`2035`	`2035`	`"column-specific target set via ALTER TABLE SET STATISTICS.")`
`2036`	`2036`	`},`
`2037`	`2037`	`&default_statistics_target,`
`2038`		`- 100, 1, 10000,`
	`2038`	`+ 100, 1, MAX_STATISTICS_TARGET,`
`2039`	`2039`	`NULL, NULL, NULL`
`2040`	`2040`	`},`
`2041`	`2041`	`{`
Original file line number	Diff line number	Diff line change
`@@ -165,7 +165,7 @@ CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,`
`165`	`165`	`* that no value has been explicitly set for this column, so ANALYZE`
`166`	`166`	`* should use the default setting.`
`167`	`167`	`*`
`168`		`- * int16 is sufficient because the max value is currently 10000.`
	`168`	`+ * int16 is sufficient for the current max value (MAX_STATISTICS_TARGET).`
`169`	`169`	`*/`
`170`	`170`	`int16 attstattarget BKI_DEFAULT(-1);`
`171`	`171`