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Make the name optional in CREATE STATISTICS.
This allows users to omit the statistics name in a CREATE STATISTICS command, letting the system auto-generate a sensible, unique name, putting the statistics object in the same schema as the table. Simon Riggs, reviewed by Matthias van de Meent. Discussion: https://postgr.es/m/CANbhV-FGD2d_C3zFTfT2aRfX_TaPSgOeKES58RLZx5XzQp5NhA@mail.gmail.com
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‎doc/src/sgml/ref/create_statistics.sgml‎

Lines changed: 8 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -21,11 +21,11 @@ PostgreSQL documentation
2121

2222
<refsynopsisdiv>
2323
<synopsis>
24-
CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
24+
CREATE STATISTICS [ [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable> ]
2525
ON ( <replaceable class="parameter">expression</replaceable> )
2626
FROM <replaceable class="parameter">table_name</replaceable>
2727

28-
CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
28+
CREATE STATISTICS [ [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable> ]
2929
[ ( <replaceable class="parameter">statistics_kind</replaceable> [, ... ] ) ]
3030
ON { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) }, { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [, ...]
3131
FROM <replaceable class="parameter">table_name</replaceable>
@@ -60,8 +60,8 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
6060
If a schema name is given (for example, <literal>CREATE STATISTICS
6161
myschema.mystat ...</literal>) then the statistics object is created in the
6262
specified schema. Otherwise it is created in the current schema.
63-
The name of the statistics object must be distinct from the name of any
64-
other statistics object in the same schema.
63+
If given, the name of the statistics object must be distinct from the name
64+
of any other statistics object in the same schema.
6565
</para>
6666
</refsect1>
6767

@@ -78,6 +78,7 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
7878
exists. A notice is issued in this case. Note that only the name of
7979
the statistics object is considered here, not the details of its
8080
definition.
81+
Statistics name is required when <literal>IF NOT EXISTS</literal> is specified.
8182
</para>
8283
</listitem>
8384
</varlistentry>
@@ -88,6 +89,9 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
8889
<para>
8990
The name (optionally schema-qualified) of the statistics object to be
9091
created.
92+
If the name is omitted, <productname>PostgreSQL</productname> chooses a
93+
suitable name based on the parent table's name and the defined column
94+
name(s) and/or expression(s).
9195
</para>
9296
</listitem>
9397
</varlistentry>

‎src/backend/commands/statscmds.c‎

Lines changed: 3 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -155,10 +155,9 @@ CreateStatistics(CreateStatsStmt *stmt)
155155

156156
/*
157157
* If the node has a name, split it up and determine creation namespace.
158-
* If not (a possibility not considered by the grammar, but one which can
159-
* occur via the "CREATE TABLE ... (LIKE)" command), then we put the
160-
* object in the same namespace as the relation, and cons up a name for
161-
* it.
158+
* If not, put the object in the same namespace as the relation, and cons
159+
* up a name for it. (This can happen either via "CREATE STATISTICS ..."
160+
* or via "CREATE TABLE ... (LIKE)".)
162161
*/
163162
if (stmt->defnames)
164163
namespaceId = QualifiedNameGetCreationNamespace(stmt->defnames,

‎src/backend/parser/gram.y‎

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -434,7 +434,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
434434
old_aggr_definition old_aggr_list
435435
oper_argtypes RuleActionList RuleActionMulti
436436
opt_column_list columnList opt_name_list
437-
sort_clause opt_sort_clause sortby_list index_params stats_params
437+
sort_clause opt_sort_clause sortby_list index_params
438+
opt_stats_name stats_params
438439
opt_include opt_c_include index_including_params
439440
name_list role_list from_clause from_list opt_array_bounds
440441
qualified_name_list any_name any_name_list type_name_list
@@ -4533,7 +4534,7 @@ ExistingIndex: USING INDEX name { $$ = $3; }
45334534
/*****************************************************************************
45344535
*
45354536
* QUERY :
4536-
* CREATE STATISTICS [IF NOT EXISTS] stats_name [(stat types)]
4537+
* CREATE STATISTICS [[IF NOT EXISTS] stats_name] [(stat types)]
45374538
* ON expression-list FROM from_list
45384539
*
45394540
* Note: the expectation here is that the clauses after ON are a subset of
@@ -4545,7 +4546,7 @@ ExistingIndex: USING INDEX name { $$ = $3; }
45454546
*****************************************************************************/
45464547

45474548
CreateStatsStmt:
4548-
CREATE STATISTICS any_name
4549+
CREATE STATISTICS opt_stats_name
45494550
opt_name_list ON stats_params FROM from_list
45504551
{
45514552
CreateStatsStmt *n = makeNode(CreateStatsStmt);
@@ -4573,6 +4574,12 @@ CreateStatsStmt:
45734574
}
45744575
;
45754576

4577+
/* Statistics name is optional unless IF NOT EXISTS is specified */
4578+
opt_stats_name:
4579+
any_name { $$ = $1; }
4580+
| /*EMPTY*/ { $$ = NULL; }
4581+
;
4582+
45764583
/*
45774584
* Statistics attributes can be either simple column references, or arbitrary
45784585
* expressions in parens. For compatibility with index attributes permitted

‎src/test/regress/expected/stats_ext.out‎

Lines changed: 51 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -3062,11 +3062,11 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
30623062
ANALYZE tststats.priv_test_tbl;
30633063
-- Check printing info about extended statistics by \dX
30643064
create table stts_t1 (a int, b int);
3065-
create statistics stts_1 (ndistinct) on a, b from stts_t1;
3066-
create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
3067-
create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
3065+
create statistics (ndistinct) on a, b from stts_t1;
3066+
create statistics (ndistinct, dependencies) on a, b from stts_t1;
3067+
create statistics (ndistinct, dependencies, mcv) on a, b from stts_t1;
30683068
create table stts_t2 (a int, b int, c int);
3069-
create statistics stts_4 on b, c from stts_t2;
3069+
create statistics on b, c from stts_t2;
30703070
create table stts_t3 (col1 int, col2 int, col3 int);
30713071
create statistics stts_hoge on col1, col2, col3 from stts_t3;
30723072
create schema stts_s1;
@@ -3084,24 +3084,24 @@ set search_path to public, stts_s1, stts_s2, tststats;
30843084
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
30853085
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
30863086
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
3087-
public | stts_1 | a, b FROM stts_t1 | defined | |
3088-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3089-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3090-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
30913087
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
3088+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3089+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3090+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3091+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
30923092
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
30933093
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
30943094
tststats | priv_test_stats | a, b FROM priv_test_tbl | | | defined
30953095
(12 rows)
30963096

3097-
\dX stts_?
3098-
List of extended statistics
3099-
Schema | Name | Definition | Ndistinct | Dependencies | MCV
3100-
--------+--------+-------------------+-----------+--------------+---------
3101-
public | stts_1 | a, b FROM stts_t1 | defined | |
3102-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3103-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3104-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
3097+
\dX stts_t*
3098+
List of extended statistics
3099+
Schema | Name | Definition | Ndistinct | Dependencies | MCV
3100+
--------+-------------------+-------------------+-----------+--------------+---------
3101+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3102+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3103+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3104+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
31053105
(4 rows)
31063106

31073107
\dX *stts_hoge
@@ -3119,24 +3119,24 @@ set search_path to public, stts_s1, stts_s2, tststats;
31193119
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
31203120
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
31213121
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
3122-
public | stts_1 | a, b FROM stts_t1 | defined | |
3123-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3124-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3125-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
31263122
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
3123+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3124+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3125+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3126+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
31273127
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
31283128
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
31293129
tststats | priv_test_stats | a, b FROM priv_test_tbl | | | defined
31303130
(12 rows)
31313131

3132-
\dX+ stts_?
3133-
List of extended statistics
3134-
Schema | Name | Definition | Ndistinct | Dependencies | MCV
3135-
--------+--------+-------------------+-----------+--------------+---------
3136-
public | stts_1 | a, b FROM stts_t1 | defined | |
3137-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3138-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3139-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
3132+
\dX+ stts_t*
3133+
List of extended statistics
3134+
Schema | Name | Definition | Ndistinct | Dependencies | MCV
3135+
--------+-------------------+-------------------+-----------+--------------+---------
3136+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3137+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3138+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3139+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
31403140
(4 rows)
31413141

31423142
\dX+ *stts_hoge
@@ -3153,6 +3153,21 @@ set search_path to public, stts_s1, stts_s2, tststats;
31533153
stts_s2 | stts_yama | col1, col3 FROM stts_t3 | | defined | defined
31543154
(1 row)
31553155

3156+
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
3157+
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
3158+
create statistics (mcv) ON (a+b), (a-b) FROM stts_t1;
3159+
\dX stts_t*expr*
3160+
List of extended statistics
3161+
Schema | Name | Definition | Ndistinct | Dependencies | MCV
3162+
--------+-----------------------------+-------------------------------------+-----------+--------------+---------
3163+
public | stts_t1_a_b_expr_expr_stat | a, b, (a + b), (a - b) FROM stts_t1 | | | defined
3164+
public | stts_t1_a_b_expr_expr_stat1 | a, b, (a + b), (a - b) FROM stts_t1 | | | defined
3165+
public | stts_t1_expr_expr_stat | (a + b), (a - b) FROM stts_t1 | | | defined
3166+
(3 rows)
3167+
3168+
drop statistics stts_t1_a_b_expr_expr_stat;
3169+
drop statistics stts_t1_a_b_expr_expr_stat1;
3170+
drop statistics stts_t1_expr_expr_stat;
31563171
set search_path to public, stts_s1;
31573172
\dX
31583173
List of extended statistics
@@ -3162,11 +3177,11 @@ set search_path to public, stts_s1;
31623177
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
31633178
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
31643179
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
3165-
public | stts_1 | a, b FROM stts_t1 | defined | |
3166-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3167-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3168-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
31693180
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
3181+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3182+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3183+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3184+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
31703185
stts_s1 | stts_foo | col1, col2 FROM stts_t3 | defined | defined | defined
31713186
(10 rows)
31723187

@@ -3180,11 +3195,11 @@ set role regress_stats_ext;
31803195
public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays | | | defined
31813196
public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool | | | defined
31823197
public | mcv_lists_stats | a, b, d FROM mcv_lists | | | defined
3183-
public | stts_1 | a, b FROM stts_t1 | defined | |
3184-
public | stts_2 | a, b FROM stts_t1 | defined | defined |
3185-
public | stts_3 | a, b FROM stts_t1 | defined | defined | defined
3186-
public | stts_4 | b, c FROM stts_t2 | defined | defined | defined
31873198
public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined | defined | defined
3199+
public | stts_t1_a_b_stat | a, b FROM stts_t1 | defined | |
3200+
public | stts_t1_a_b_stat1 | a, b FROM stts_t1 | defined | defined |
3201+
public | stts_t1_a_b_stat2 | a, b FROM stts_t1 | defined | defined | defined
3202+
public | stts_t2_b_c_stat | b, c FROM stts_t2 | defined | defined | defined
31883203
(9 rows)
31893204

31903205
reset role;

‎src/test/regress/sql/stats_ext.sql‎

Lines changed: 14 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1555,12 +1555,12 @@ ANALYZE tststats.priv_test_tbl;
15551555

15561556
-- Check printing info about extended statistics by \dX
15571557
create table stts_t1 (a int, b int);
1558-
create statistics stts_1 (ndistinct) on a, b from stts_t1;
1559-
create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
1560-
create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
1558+
create statistics (ndistinct) on a, b from stts_t1;
1559+
create statistics (ndistinct, dependencies) on a, b from stts_t1;
1560+
create statistics (ndistinct, dependencies, mcv) on a, b from stts_t1;
15611561

15621562
create table stts_t2 (a int, b int, c int);
1563-
create statistics stts_4 on b, c from stts_t2;
1563+
create statistics on b, c from stts_t2;
15641564

15651565
create table stts_t3 (col1 int, col2 int, col3 int);
15661566
create statistics stts_hoge on col1, col2, col3 from stts_t3;
@@ -1575,13 +1575,21 @@ analyze stts_t1;
15751575
set search_path to public, stts_s1, stts_s2, tststats;
15761576

15771577
\dX
1578-
\dX stts_?
1578+
\dX stts_t*
15791579
\dX *stts_hoge
15801580
\dX+
1581-
\dX+ stts_?
1581+
\dX+ stts_t*
15821582
\dX+ *stts_hoge
15831583
\dX+ stts_s2.stts_yama
15841584

1585+
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
1586+
create statistics (mcv) ON a, b, (a+b), (a-b) FROM stts_t1;
1587+
create statistics (mcv) ON (a+b), (a-b) FROM stts_t1;
1588+
\dX stts_t*expr*
1589+
drop statistics stts_t1_a_b_expr_expr_stat;
1590+
drop statistics stts_t1_a_b_expr_expr_stat1;
1591+
drop statistics stts_t1_expr_expr_stat;
1592+
15851593
set search_path to public, stts_s1;
15861594
\dX
15871595

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