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Allow SET STATISTICS on expression indexes 

Index columns are referenced by ordinal number rather than name, e.g.
CREATE INDEX coord_idx ON measured (x, y, (z + t));
ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000;

Incompatibility note for release notes:
\d+ for indexes now also displays Stats Target

Authors: Alexander Korotkov, with contribution by Adrien NAYRAT
Review: Adrien NAYRAT, Simon Riggs
Wordsmith: Simon Riggs
This commit is contained in:
Simon Riggs 2017-09-06 13:46:01 -07:00
parent e09db94c0a
commit 5b6d13eec7
13 changed files with 201 additions and 17 deletions
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39
doc/src/sgml/ref/alter_index.sgml
View File

@ -26,6 +26,8 @@ ALTER INDEX [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> SET
ALTER INDEX <replaceable class="PARAMETER">name</replaceable> DEPENDS ON EXTENSION <replaceable class="PARAMETER">extension_name</replaceable>
ALTER INDEX [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> SET ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] )
ALTER INDEX [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> RESET ( <replaceable class="PARAMETER">storage_parameter</replaceable> [, ... ] )
ALTER INDEX [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> ALTER [ COLUMN ] <replaceable class="PARAMETER">column_number</replaceable>
SET STATISTICS <replaceable class="PARAMETER">integer</replaceable>
ALTER INDEX ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable> [ OWNED BY <replaceable class="PARAMETER">role_name</replaceable> [, ... ] ]
SET TABLESPACE <replaceable class="PARAMETER">new_tablespace</replaceable> [ NOWAIT ]
</synopsis>
@ -110,6 +112,25 @@ ALTER INDEX ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>ALTER [ COLUMN ] <replaceable class="PARAMETER">column_number</replaceable> SET STATISTICS <replaceable class="PARAMETER">integer</replaceable></literal></term>
<listitem>
<para>
This form sets the per-column statistics-gathering target for
subsequent <xref linkend="sql-analyze"> 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 (<xref linkend="guc-default-statistics-target">).
For more information on the use of statistics by the
<productname>PostgreSQL</productname> query planner, refer to
<xref linkend="planner-stats">.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
@ -130,6 +151,16 @@ ALTER INDEX ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">column_number</replaceable></term>
<listitem>
<para>
The ordinal number refers to the ordinal (left-to-right) position
of the index column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">name</replaceable></term>
<listitem>
@ -235,6 +266,14 @@ ALTER INDEX distributors SET (fillfactor = 75);
REINDEX INDEX distributors;
</programlisting></para>
<para>
Set the statistics-gathering target for an expression index:
<programlisting>
CREATE INDEX coord_idx ON measured (x, y, (z + t));
ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000;
</programlisting>
</para>
</refsect1>
<refsect1>

55
src/backend/commands/tablecmds.c
View File

@ -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);

1
src/backend/nodes/copyfuncs.c
View File

@ -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);

1
src/backend/nodes/equalfuncs.c
View File

@ -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);

16
src/backend/parser/gram.y
View File

@ -2078,6 +2078,22 @@ alter_table_cmd:
n->def = (Node *) makeInteger($6);
$$ = (Node *)n;
}
/* ALTER TABLE <name> ALTER [COLUMN] <colnum> SET STATISTICS <SignedIconst> */
| ALTER opt_column Iconst SET STATISTICS SignedIconst
{
AlterTableCmd *n = makeNode(AlterTableCmd);
if ($3 <= 0 || $3 > PG_INT16_MAX)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("column number must be in range from 1 to %d", PG_INT16_MAX),
parser_errposition(@3)));
n->subtype = AT_SetStatistics;
n->num = (int16) $3;
n->def = (Node *) makeInteger($6);
$$ = (Node *)n;
}
/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET ( column_parameter = value [, ... ] ) */
| ALTER opt_column ColId SET reloptions
{

46
src/backend/utils/cache/syscache.c vendored
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@ -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
*

2
src/bin/psql/describe.c
View File

@ -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)

5
src/bin/psql/tab-complete.c
View File

@ -1644,7 +1644,10 @@ psql_completion(const char *text, int start, int end)
"UNION SELECT 'ALL IN TABLESPACE'");
/* ALTER INDEX <name> */
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 <name> ALTER COLUMN <colnum> */
else if (Matches6("ALTER", "INDEX", MatchAny, "ALTER", "COLUMN", MatchAny))
COMPLETE_WITH_CONST("SET STATISTICS");
/* ALTER INDEX <name> SET */
else if (Matches4("ALTER", "INDEX", MatchAny, "SET"))
COMPLETE_WITH_LIST2("(", "TABLESPACE");

2
src/include/nodes/parsenodes.h
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@ -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 */

3
src/include/utils/syscache.h
View File

@ -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);

24
src/test/regress/expected/alter_table.out
View File

@ -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

8
src/test/regress/expected/create_index.out
View File

@ -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

16
src/test/regress/sql/alter_table.sql
View File

@ -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;