diff --git a/doc/src/sgml/ref/alter_index.sgml b/doc/src/sgml/ref/alter_index.sgml
index ad77b5743a..7d6553d2db 100644
--- a/doc/src/sgml/ref/alter_index.sgml
+++ b/doc/src/sgml/ref/alter_index.sgml
@@ -26,6 +26,8 @@ ALTER INDEX [ IF EXISTS ] name SET
ALTER INDEX name DEPENDS ON EXTENSION extension_name
ALTER INDEX [ IF EXISTS ] name SET ( storage_parameter = value [, ... ] )
ALTER INDEX [ IF EXISTS ] name RESET ( storage_parameter [, ... ] )
+ALTER INDEX [ IF EXISTS ] name ALTER [ COLUMN ] column_number
+ SET STATISTICS integer
ALTER INDEX ALL IN TABLESPACE name [ OWNED BY role_name [, ... ] ]
SET TABLESPACE new_tablespace [ NOWAIT ]
@@ -110,6 +112,25 @@ ALTER INDEX ALL IN TABLESPACE name
+
+ ALTER [ COLUMN ] column_number SET STATISTICS integer
+
+
+ This form sets the per-column statistics-gathering target for
+ subsequent operations, though can
+ be used only on index columns that are defined as an expression.
+ Since expressions lack a unique name, we refer to them using the
+ ordinal number of the index column.
+ The target can be set in the range 0 to 10000; alternatively, set it
+ to -1 to revert to using the system default statistics
+ target ().
+ For more information on the use of statistics by the
+ PostgreSQL query planner, refer to
+ .
+
+
+
+
@@ -130,6 +151,16 @@ ALTER INDEX ALL IN TABLESPACE name
+
+ column_number
+
+
+ The ordinal number refers to the ordinal (left-to-right) position
+ of the index column.
+
+
+
+
name
@@ -235,6 +266,14 @@ ALTER INDEX distributors SET (fillfactor = 75);
REINDEX INDEX distributors;
+
+ Set the statistics-gathering target for an expression index:
+
+CREATE INDEX coord_idx ON measured (x, y, (z + t));
+ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000;
+
+
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0f08245a67..c8fc9cb7fe 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -375,9 +375,9 @@ static ObjectAddress ATExecAddIdentity(Relation rel, const char *colName,
static ObjectAddress ATExecSetIdentity(Relation rel, const char *colName,
Node *def, LOCKMODE lockmode);
static ObjectAddress ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode);
-static void ATPrepSetStatistics(Relation rel, const char *colName,
+static void ATPrepSetStatistics(Relation rel, const char *colName, int16 colNum,
Node *newValue, LOCKMODE lockmode);
-static ObjectAddress ATExecSetStatistics(Relation rel, const char *colName,
+static ObjectAddress ATExecSetStatistics(Relation rel, const char *colName, int16 colNum,
Node *newValue, LOCKMODE lockmode);
static ObjectAddress ATExecSetOptions(Relation rel, const char *colName,
Node *options, bool isReset, LOCKMODE lockmode);
@@ -3525,7 +3525,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* Performs own permission checks */
- ATPrepSetStatistics(rel, cmd->name, cmd->def, lockmode);
+ ATPrepSetStatistics(rel, cmd->name, cmd->num, cmd->def, lockmode);
pass = AT_PASS_MISC;
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options ) */
@@ -3848,7 +3848,7 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
address = ATExecSetNotNull(tab, rel, cmd->name, lockmode);
break;
case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */
- address = ATExecSetStatistics(rel, cmd->name, cmd->def, lockmode);
+ address = ATExecSetStatistics(rel, cmd->name, cmd->num, cmd->def, lockmode);
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options ) */
address = ATExecSetOptions(rel, cmd->name, cmd->def, false, lockmode);
@@ -6120,7 +6120,7 @@ ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE
* ALTER TABLE ALTER COLUMN SET STATISTICS
*/
static void
-ATPrepSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE lockmode)
+ATPrepSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newValue, LOCKMODE lockmode)
{
/*
* We do our own permission checking because (a) we want to allow SET
@@ -6138,6 +6138,15 @@ ATPrepSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE
errmsg("\"%s\" is not a table, materialized view, index, or foreign table",
RelationGetRelationName(rel))));
+ /*
+ * We allow referencing columns by numbers only for indexes, since
+ * table column numbers could contain gaps if columns are later dropped.
+ */
+ if (rel->rd_rel->relkind != RELKIND_INDEX && !colName)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot refer to non-index column by number")));
+
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
@@ -6148,7 +6157,7 @@ ATPrepSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE
* Return value is the address of the modified column
*/
static ObjectAddress
-ATExecSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE lockmode)
+ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newValue, LOCKMODE lockmode)
{
int newtarget;
Relation attrelation;
@@ -6181,13 +6190,27 @@ ATExecSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
- tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+ if (colName)
+ {
+ tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+
+ if (!HeapTupleIsValid(tuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" of relation \"%s\" does not exist",
+ colName, RelationGetRelationName(rel))));
+ }
+ else
+ {
+ tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), colNum);
+
+ if (!HeapTupleIsValid(tuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column number %d of relation \"%s\" does not exist",
+ colNum, RelationGetRelationName(rel))));
+ }
- if (!HeapTupleIsValid(tuple))
- ereport(ERROR,
- (errcode(ERRCODE_UNDEFINED_COLUMN),
- errmsg("column \"%s\" of relation \"%s\" does not exist",
- colName, RelationGetRelationName(rel))));
attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = attrtuple->attnum;
@@ -6197,6 +6220,14 @@ ATExecSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE
errmsg("cannot alter system column \"%s\"",
colName)));
+ if (rel->rd_rel->relkind == RELKIND_INDEX &&
+ rel->rd_index->indkey.values[attnum - 1] != 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot alter statistics on non-expression column \"%s\" of index \"%s\"",
+ NameStr(attrtuple->attname), RelationGetRelationName(rel)),
+ errhint("Alter statistics on table column instead.")));
+
attrtuple->attstattarget = newtarget;
CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index f9ddf4ed76..9bae2647fd 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3087,6 +3087,7 @@ _copyAlterTableCmd(const AlterTableCmd *from)
COPY_SCALAR_FIELD(subtype);
COPY_STRING_FIELD(name);
+ COPY_SCALAR_FIELD(num);
COPY_NODE_FIELD(newowner);
COPY_NODE_FIELD(def);
COPY_SCALAR_FIELD(behavior);
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 8d92c03633..11731da80a 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1098,6 +1098,7 @@ _equalAlterTableCmd(const AlterTableCmd *a, const AlterTableCmd *b)
{
COMPARE_SCALAR_FIELD(subtype);
COMPARE_STRING_FIELD(name);
+ COMPARE_SCALAR_FIELD(num);
COMPARE_NODE_FIELD(newowner);
COMPARE_NODE_FIELD(def);
COMPARE_SCALAR_FIELD(behavior);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 7d0de99baf..5eb398118e 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2078,6 +2078,22 @@ alter_table_cmd:
n->def = (Node *) makeInteger($6);
$$ = (Node *)n;
}
+ /* ALTER TABLE ALTER [COLUMN] SET STATISTICS */
+ | ALTER opt_column Iconst SET STATISTICS SignedIconst
+ {
+ AlterTableCmd *n = makeNode(AlterTableCmd);
+
+ if ($3 <= 0 || $3 > PG_INT16_MAX)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("column number must be in range from 1 to %d", PG_INT16_MAX),
+ parser_errposition(@3)));
+
+ n->subtype = AT_SetStatistics;
+ n->num = (int16) $3;
+ n->def = (Node *) makeInteger($6);
+ $$ = (Node *)n;
+ }
/* ALTER TABLE ALTER [COLUMN] SET ( column_parameter = value [, ... ] ) */
| ALTER opt_column ColId SET reloptions
{
diff --git a/src/backend/utils/cache/syscache.c b/src/backend/utils/cache/syscache.c
index 607fe9db79..fcbb683a99 100644
--- a/src/backend/utils/cache/syscache.c
+++ b/src/backend/utils/cache/syscache.c
@@ -1256,6 +1256,52 @@ SearchSysCacheExistsAttName(Oid relid, const char *attname)
}
+/*
+ * SearchSysCacheAttNum
+ *
+ * This routine is equivalent to SearchSysCache on the ATTNUM cache,
+ * except that it will return NULL if the found attribute is marked
+ * attisdropped. This is convenient for callers that want to act as
+ * though dropped attributes don't exist.
+ */
+HeapTuple
+SearchSysCacheAttNum(Oid relid, int16 attnum)
+{
+ HeapTuple tuple;
+
+ tuple = SearchSysCache2(ATTNUM,
+ ObjectIdGetDatum(relid),
+ Int16GetDatum(attnum));
+ if (!HeapTupleIsValid(tuple))
+ return NULL;
+ if (((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped)
+ {
+ ReleaseSysCache(tuple);
+ return NULL;
+ }
+ return tuple;
+}
+
+/*
+ * SearchSysCacheCopyAttNum
+ *
+ * As above, an attisdropped-aware version of SearchSysCacheCopy.
+ */
+HeapTuple
+SearchSysCacheCopyAttNum(Oid relid, int16 attnum)
+{
+ HeapTuple tuple,
+ newtuple;
+
+ tuple = SearchSysCacheAttNum(relid, attnum);
+ if (!HeapTupleIsValid(tuple))
+ return NULL;
+ newtuple = heap_copytuple(tuple);
+ ReleaseSysCache(tuple);
+ return newtuple;
+}
+
+
/*
* SysCacheGetAttr
*
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f6049cc9e5..6fb9bdd063 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -1742,6 +1742,7 @@ describeOneTableDetails(const char *schemaname,
{
headers[cols++] = gettext_noop("Storage");
if (tableinfo.relkind == RELKIND_RELATION ||
+ tableinfo.relkind == RELKIND_INDEX ||
tableinfo.relkind == RELKIND_MATVIEW ||
tableinfo.relkind == RELKIND_FOREIGN_TABLE ||
tableinfo.relkind == RELKIND_PARTITIONED_TABLE)
@@ -1841,6 +1842,7 @@ describeOneTableDetails(const char *schemaname,
/* Statistics target, if the relkind supports this feature */
if (tableinfo.relkind == RELKIND_RELATION ||
+ tableinfo.relkind == RELKIND_INDEX ||
tableinfo.relkind == RELKIND_MATVIEW ||
tableinfo.relkind == RELKIND_FOREIGN_TABLE ||
tableinfo.relkind == RELKIND_PARTITIONED_TABLE)
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 7959f9ac16..2ab8809fa5 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1644,7 +1644,10 @@ psql_completion(const char *text, int start, int end)
"UNION SELECT 'ALL IN TABLESPACE'");
/* ALTER INDEX */
else if (Matches3("ALTER", "INDEX", MatchAny))
- COMPLETE_WITH_LIST4("OWNER TO", "RENAME TO", "SET", "RESET");
+ COMPLETE_WITH_LIST5("ALTER COLUMN", "OWNER TO", "RENAME TO", "SET", "RESET");
+ /* ALTER INDEX ALTER COLUMN */
+ else if (Matches6("ALTER", "INDEX", MatchAny, "ALTER", "COLUMN", MatchAny))
+ COMPLETE_WITH_CONST("SET STATISTICS");
/* ALTER INDEX SET */
else if (Matches4("ALTER", "INDEX", MatchAny, "SET"))
COMPLETE_WITH_LIST2("(", "TABLESPACE");
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index ef6753e31a..3171815320 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1777,6 +1777,8 @@ typedef struct AlterTableCmd /* one subcommand of an ALTER TABLE */
AlterTableType subtype; /* Type of table alteration to apply */
char *name; /* column, constraint, or trigger to act on,
* or tablespace */
+ int16 num; /* attribute number for columns referenced
+ * by number */
RoleSpec *newowner;
Node *def; /* definition of new column, index,
* constraint, or parent table */
diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index 8352b40f4e..8a92ea27ac 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -131,6 +131,9 @@ extern HeapTuple SearchSysCacheAttName(Oid relid, const char *attname);
extern HeapTuple SearchSysCacheCopyAttName(Oid relid, const char *attname);
extern bool SearchSysCacheExistsAttName(Oid relid, const char *attname);
+extern HeapTuple SearchSysCacheAttNum(Oid relid, int16 attnum);
+extern HeapTuple SearchSysCacheCopyAttNum(Oid relid, int16 attnum);
+
extern Datum SysCacheGetAttr(int cacheId, HeapTuple tup,
AttrNumber attributeNumber, bool *isNull);
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index ed03cb9c63..0f36423163 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -94,6 +94,30 @@ SELECT * FROM tmp;
| 4 | name | text | 4.1 | 4.1 | 2 | ((4.1,4.1),(3.1,3.1)) | Mon May 01 00:30:30 1995 PDT | c | {"Mon May 01 00:30:30 1995 PDT","Mon Aug 24 14:43:07 1992 PDT","Wed Dec 31 16:00:00 1969 PST"} | 314159 | (1,1) | 512 | 1 2 3 4 5 6 7 8 | magnetic disk | (1.1,1.1) | [(4.1,4.1),(3.1,3.1)] | ((0,2),(4.1,4.1),(3.1,3.1)) | (4.1,4.1),(3.1,3.1) | ["Wed Dec 31 16:00:00 1969 PST" "infinity"] | Thu Jan 01 00:00:00 1970 | @ 1 hour 10 secs | {1,2,3,4} | {1,2,3,4} | {1,2,3,4}
(1 row)
+CREATE INDEX tmp_idx ON tmp (a, (d + e), b);
+ALTER INDEX tmp_idx ALTER COLUMN 0 SET STATISTICS 1000;
+ERROR: column number must be in range from 1 to 32767
+LINE 1: ALTER INDEX tmp_idx ALTER COLUMN 0 SET STATISTICS 1000;
+ ^
+ALTER INDEX tmp_idx ALTER COLUMN 1 SET STATISTICS 1000;
+ERROR: cannot alter statistics on non-expression column "a" of index "tmp_idx"
+HINT: Alter statistics on table column instead.
+ALTER INDEX tmp_idx ALTER COLUMN 2 SET STATISTICS 1000;
+\d+ tmp_idx
+ Index "public.tmp_idx"
+ Column | Type | Definition | Storage | Stats target
+--------+------------------+------------+---------+--------------
+ a | integer | a | plain |
+ expr | double precision | (d + e) | plain | 1000
+ b | cstring | b | plain |
+btree, for table "public.tmp"
+
+ALTER INDEX tmp_idx ALTER COLUMN 3 SET STATISTICS 1000;
+ERROR: cannot alter statistics on non-expression column "b" of index "tmp_idx"
+HINT: Alter statistics on table column instead.
+ALTER INDEX tmp_idx ALTER COLUMN 4 SET STATISTICS 1000;
+ERROR: column number 4 of relation "tmp_idx" does not exist
+ALTER INDEX tmp_idx ALTER COLUMN 2 SET STATISTICS -1;
DROP TABLE tmp;
--
-- rename - check on both non-temp and temp tables
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index 064adb4640..8450f2463e 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2324,10 +2324,10 @@ DROP TABLE array_gin_test;
CREATE INDEX gin_relopts_test ON array_index_op_test USING gin (i)
WITH (FASTUPDATE=on, GIN_PENDING_LIST_LIMIT=128);
\d+ gin_relopts_test
- Index "public.gin_relopts_test"
- Column | Type | Definition | Storage
---------+---------+------------+---------
- i | integer | i | plain
+ Index "public.gin_relopts_test"
+ Column | Type | Definition | Storage | Stats target
+--------+---------+------------+---------+--------------
+ i | integer | i | plain |
gin, for table "public.array_index_op_test"
Options: fastupdate=on, gin_pending_list_limit=128
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 9a20dd141a..e6f6669880 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -142,6 +142,22 @@ INSERT INTO tmp (a, b, c, d, e, f, g, h, i, j, k, l, m, n, p, q, r, s, t, u,
SELECT * FROM tmp;
+CREATE INDEX tmp_idx ON tmp (a, (d + e), b);
+
+ALTER INDEX tmp_idx ALTER COLUMN 0 SET STATISTICS 1000;
+
+ALTER INDEX tmp_idx ALTER COLUMN 1 SET STATISTICS 1000;
+
+ALTER INDEX tmp_idx ALTER COLUMN 2 SET STATISTICS 1000;
+
+\d+ tmp_idx
+
+ALTER INDEX tmp_idx ALTER COLUMN 3 SET STATISTICS 1000;
+
+ALTER INDEX tmp_idx ALTER COLUMN 4 SET STATISTICS 1000;
+
+ALTER INDEX tmp_idx ALTER COLUMN 2 SET STATISTICS -1;
+
DROP TABLE tmp;