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Add result_types column to pg_prepared_statements view
Containing the types of the columns returned by the prepared statement. Prompted by question from IRC user mlvzk. Author: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://www.postgresql.org/message-id/flat/871qwpo7te.fsf@wibble.ilmari.org
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7 files changed

+74
-52
lines changed

7 files changed

+74
-52
lines changed

‎doc/src/sgml/catalogs.sgml‎

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -11502,6 +11502,18 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
1150211502
</para></entry>
1150311503
</row>
1150411504

11505+
<row>
11506+
<entry role="catalog_table_entry"><para role="column_definition">
11507+
<structfield>result_types</structfield> <type>regtype[]</type>
11508+
</para>
11509+
<para>
11510+
The types of the columns returned by the prepared statement in the
11511+
form of an array of <type>regtype</type>. The OID corresponding
11512+
to an element of this array can be obtained by casting the
11513+
<type>regtype</type> value to <type>oid</type>.
11514+
</para></entry>
11515+
</row>
11516+
1150511517
<row>
1150611518
<entry role="catalog_table_entry"><para role="column_definition">
1150711519
<structfield>from_sql</structfield> <type>bool</type>

‎src/backend/commands/prepare.c‎

Lines changed: 14 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -683,8 +683,16 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
683683
hash_seq_init(&hash_seq, prepared_queries);
684684
while ((prep_stmt = hash_seq_search(&hash_seq)) != NULL)
685685
{
686-
Datum values[7];
687-
bool nulls[7];
686+
TupleDesc result_desc;
687+
Oid *result_types;
688+
Datum values[8];
689+
bool nulls[8];
690+
691+
result_desc = prep_stmt->plansource->resultDesc;
692+
result_types = (Oid *) palloc(result_desc->natts * sizeof(Oid));
693+
694+
for (int i = 0; i < result_desc->natts; i++)
695+
result_types[i] = result_desc->attrs[i].atttypid;
688696

689697
MemSet(nulls, 0, sizeof(nulls));
690698

@@ -693,9 +701,10 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
693701
values[2] = TimestampTzGetDatum(prep_stmt->prepare_time);
694702
values[3] = build_regtype_array(prep_stmt->plansource->param_types,
695703
prep_stmt->plansource->num_params);
696-
values[4] = BoolGetDatum(prep_stmt->from_sql);
697-
values[5] = Int64GetDatumFast(prep_stmt->plansource->num_generic_plans);
698-
values[6] = Int64GetDatumFast(prep_stmt->plansource->num_custom_plans);
704+
values[4] = build_regtype_array(result_types, result_desc->natts);
705+
values[5] = BoolGetDatum(prep_stmt->from_sql);
706+
values[6] = Int64GetDatumFast(prep_stmt->plansource->num_generic_plans);
707+
values[7] = Int64GetDatumFast(prep_stmt->plansource->num_custom_plans);
699708

700709
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
701710
values, nulls);

‎src/include/catalog/catversion.h‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -53,6 +53,6 @@
5353
*/
5454

5555
/* yyyymmddN */
56-
#define CATALOG_VERSION_NO 202205191
56+
#define CATALOG_VERSION_NO 202207051
5757

5858
#endif

‎src/include/catalog/pg_proc.dat‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8025,9 +8025,9 @@
80258025
proname => 'pg_prepared_statement', prorows => '1000', proretset => 't',
80268026
provolatile => 's', proparallel => 'r', prorettype => 'record',
80278027
proargtypes => '',
8028-
proallargtypes => '{text,text,timestamptz,_regtype,bool,int8,int8}',
8029-
proargmodes => '{o,o,o,o,o,o,o}',
8030-
proargnames => '{name,statement,prepare_time,parameter_types,from_sql,generic_plans,custom_plans}',
8028+
proallargtypes => '{text,text,timestamptz,_regtype,_regtype,bool,int8,int8}',
8029+
proargmodes => '{o,o,o,o,o,o,o,o}',
8030+
proargnames => '{name,statement,prepare_time,parameter_types,result_types,from_sql,generic_plans,custom_plans}',
80318031
prosrc => 'pg_prepared_statement' },
80328032
{ oid => '2511', descr => 'get the open cursors for this session',
80338033
proname => 'pg_cursor', prorows => '1000', proretset => 't',

‎src/test/regress/expected/prepare.out‎

Lines changed: 36 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,9 @@
11
-- Regression tests for prepareable statements. We query the content
22
-- of the pg_prepared_statements view as prepared statements are
33
-- created and removed.
4-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
5-
name | statement | parameter_types
6-
------+-----------+-----------------
4+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
5+
name | statement | parameter_types | result_types
6+
------+-----------+-----------------+--------------
77
(0 rows)
88

99
PREPARE q1 AS SELECT 1 AS a;
@@ -13,10 +13,10 @@ EXECUTE q1;
1313
1
1414
(1 row)
1515

16-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
17-
name | statement | parameter_types
18-
------+------------------------------+-----------------
19-
q1 | PREPARE q1 AS SELECT 1 AS a; | {}
16+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
17+
name | statement | parameter_types | result_types
18+
------+------------------------------+-----------------+--------------
19+
q1 | PREPARE q1 AS SELECT 1 AS a; | {} | {integer}
2020
(1 row)
2121

2222
-- should fail
@@ -32,26 +32,26 @@ EXECUTE q1;
3232
(1 row)
3333

3434
PREPARE q2 AS SELECT 2 AS b;
35-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
36-
name | statement | parameter_types
37-
------+------------------------------+-----------------
38-
q1 | PREPARE q1 AS SELECT 2; | {}
39-
q2 | PREPARE q2 AS SELECT 2 AS b; | {}
35+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
36+
name | statement | parameter_types | result_types
37+
------+------------------------------+-----------------+--------------
38+
q1 | PREPARE q1 AS SELECT 2; | {} | {integer}
39+
q2 | PREPARE q2 AS SELECT 2 AS b; | {} | {integer}
4040
(2 rows)
4141

4242
-- sql92 syntax
4343
DEALLOCATE PREPARE q1;
44-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
45-
name | statement | parameter_types
46-
------+------------------------------+-----------------
47-
q2 | PREPARE q2 AS SELECT 2 AS b; | {}
44+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
45+
name | statement | parameter_types | result_types
46+
------+------------------------------+-----------------+--------------
47+
q2 | PREPARE q2 AS SELECT 2 AS b; | {} | {integer}
4848
(1 row)
4949

5050
DEALLOCATE PREPARE q2;
5151
-- the view should return the empty set again
52-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
53-
name | statement | parameter_types
54-
------+-----------+-----------------
52+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
53+
name | statement | parameter_types | result_types
54+
------+-----------+-----------------+--------------
5555
(0 rows)
5656

5757
-- parameterized queries
@@ -159,24 +159,24 @@ PREPARE q6 AS
159159
SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2;
160160
PREPARE q7(unknown) AS
161161
SELECT * FROM road WHERE thepath = $1;
162-
SELECT name, statement, parameter_types FROM pg_prepared_statements
162+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements
163163
ORDER BY name;
164-
name | statement | parameter_types
165-
------+------------------------------------------------------------------+----------------------------------------------------
166-
q2 | PREPARE q2(text) AS +| {text}
167-
| SELECT datname, datistemplate, datallowconn +|
168-
| FROM pg_database WHERE datname = $1; |
169-
q3 | PREPARE q3(text, int, float, boolean, smallint) AS +| {text,integer,"double precision",boolean,smallint}
170-
| SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR+|
171-
| ten = $3::bigint OR true = $4 OR odd = $5::int) +|
172-
| ORDER BY unique1; |
173-
q5 | PREPARE q5(int, text) AS +| {integer,text}
174-
| SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2 +|
175-
| ORDER BY unique1; |
176-
q6 | PREPARE q6 AS +| {integer,name}
177-
| SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2; |
178-
q7 | PREPARE q7(unknown) AS +| {path}
179-
| SELECT * FROM road WHERE thepath = $1; |
164+
name | statement | parameter_types | result_types
165+
------+------------------------------------------------------------------+----------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------
166+
q2 | PREPARE q2(text) AS +| {text} | {name,boolean,boolean}
167+
| SELECT datname, datistemplate, datallowconn +| |
168+
| FROM pg_database WHERE datname = $1; | |
169+
q3 | PREPARE q3(text, int, float, boolean, smallint) AS +| {text,integer,"double precision",boolean,smallint} | {integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,name,name,name}
170+
| SELECT * FROM tenk1 WHERE string4 = $1 AND (four = $2 OR+| |
171+
| ten = $3::bigint OR true = $4 OR odd = $5::int) +| |
172+
| ORDER BY unique1; | |
173+
q5 | PREPARE q5(int, text) AS +| {integer,text} | {integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,name,name,name}
174+
| SELECT * FROM tenk1 WHERE unique1 = $1 OR stringu1 = $2 +| |
175+
| ORDER BY unique1; | |
176+
q6 | PREPARE q6 AS +| {integer,name} | {integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,integer,name,name,name}
177+
| SELECT * FROM tenk1 WHERE unique1 = $1 AND stringu1 = $2; | |
178+
q7 | PREPARE q7(unknown) AS +| {path} | {text,path}
179+
| SELECT * FROM road WHERE thepath = $1; | |
180180
(5 rows)
181181

182182
-- test DEALLOCATE ALL;

‎src/test/regress/expected/rules.out‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1423,10 +1423,11 @@ pg_prepared_statements| SELECT p.name,
14231423
p.statement,
14241424
p.prepare_time,
14251425
p.parameter_types,
1426+
p.result_types,
14261427
p.from_sql,
14271428
p.generic_plans,
14281429
p.custom_plans
1429-
FROM pg_prepared_statement() p(name, statement, prepare_time, parameter_types, from_sql, generic_plans, custom_plans);
1430+
FROM pg_prepared_statement() p(name, statement, prepare_time, parameter_types, result_types, from_sql, generic_plans, custom_plans);
14301431
pg_prepared_xacts| SELECT p.transaction,
14311432
p.gid,
14321433
p.prepared,

‎src/test/regress/sql/prepare.sql‎

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -2,12 +2,12 @@
22
-- of the pg_prepared_statements view as prepared statements are
33
-- created and removed.
44

5-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
5+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
66

77
PREPARE q1 AS SELECT 1 AS a;
88
EXECUTE q1;
99

10-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
10+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
1111

1212
-- should fail
1313
PREPARE q1 AS SELECT 2;
@@ -18,16 +18,16 @@ PREPARE q1 AS SELECT 2;
1818
EXECUTE q1;
1919

2020
PREPARE q2 AS SELECT 2 AS b;
21-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
21+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
2222

2323
-- sql92 syntax
2424
DEALLOCATE PREPARE q1;
2525

26-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
26+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
2727

2828
DEALLOCATE PREPARE q2;
2929
-- the view should return the empty set again
30-
SELECT name, statement, parameter_types FROM pg_prepared_statements;
30+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
3131

3232
-- parameterized queries
3333
PREPARE q2(text) AS
@@ -71,7 +71,7 @@ PREPARE q6 AS
7171
PREPARE q7(unknown) AS
7272
SELECT * FROM road WHERE thepath = $1;
7373

74-
SELECT name, statement, parameter_types FROM pg_prepared_statements
74+
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements
7575
ORDER BY name;
7676

7777
-- test DEALLOCATE ALL;

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