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Commit2f0baa2

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Accept relations of any kind in LOCK TABLE
The restriction that only tables and views can be locked by LOCK TABLEis quite arbitrary, since the underlying mechanism can lock any relationtype. Drop the restriction so that programs such as pg_dump can lockall relations they're interested in, preventing schema changes thatcould cause a dump to fail after expending much effort.Backpatch to 9.5.Author: Álvaro Herrera <alvherre@alvh.no-ip.org>Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>Reported-by: Wells Oliver <wells.oliver@gmail.com>Discussion:https://postgr.es/m/20201021200659.GA32358@alvherre.pgsql
1 parent2339038 commit2f0baa2

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-21
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4 files changed

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‎doc/src/sgml/ref/lock.sgml

Lines changed: 12 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -16,7 +16,7 @@ PostgreSQL documentation
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<refnamediv>
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<refname>LOCK</refname>
19-
<refpurpose>lock a table</refpurpose>
19+
<refpurpose>lock anamed relation (table, etc)</refpurpose>
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</refnamediv>
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2222
<refsynopsisdiv>
@@ -34,7 +34,9 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="PARAMETER">name</replaceable> [ * ]
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<title>Description</title>
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<para>
37-
<command>LOCK TABLE</command> obtains a table-level lock, waiting
37+
<command>LOCK TABLE</command> obtains a table-level lock on a
38+
relation (table, partitioned table, foreign table, view,
39+
materialized view, index, composite type, sequence), waiting
3840
if necessary for any conflicting locks to be released. If
3941
<literal>NOWAIT</literal> is specified, <command>LOCK
4042
TABLE</command> does not wait to acquire the desired lock: if it
@@ -110,17 +112,18 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="PARAMETER">name</replaceable> [ * ]
110112
<term><replaceable class="PARAMETER">name</replaceable></term>
111113
<listitem>
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<para>
113-
The name (optionally schema-qualified) of an existingtable to
114-
lock. If <literal>ONLY</> is specified beforethe table name, only that
115-
table is locked. If <literal>ONLY</> is not specified, the table and all
116-
its descendant tables (if any) are locked. Optionally, <literal>*</>
115+
The name (optionally schema-qualified) of an existingrelation to
116+
lock. If <literal>ONLY</literal> is specified beforea table name, only that
117+
table is locked. If <literal>ONLY</literal> is not specified, the table and all
118+
its descendant tables (if any) are locked. Optionally, <literal>*</literal>
117119
can be specified after the table name to explicitly indicate that
118-
descendant tables are included.
120+
descendant tables are included. When locking a view, all relations appearing
121+
in the view definition are locked, regardless of <literal>ONLY</literal>.
119122
</para>
120123

121124
<para>
122-
The command <literal>LOCK TABLE a, b;</> is equivalent to
123-
<literal>LOCK TABLE a; LOCK TABLE b;</>. Thetables are locked
125+
The command <literal>LOCK TABLE a, b;</literal> is equivalent to
126+
<literal>LOCK TABLE a; LOCK TABLE b;</literal>. Therelations are locked
124127
one-by-one in the order specified in the <command>LOCK
125128
TABLE</command> command.
126129
</para>

‎src/backend/commands/lockcmds.c

Lines changed: 0 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -88,13 +88,6 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
8888
return;/* woops, concurrently dropped; no permissions
8989
* check */
9090

91-
/* Currently, we only allow plain tables to be locked */
92-
if (relkind!=RELKIND_RELATION&&relkind!=RELKIND_PARTITIONED_TABLE)
93-
ereport(ERROR,
94-
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
95-
errmsg("\"%s\" is not a table",
96-
rv->relname)));
97-
9891
/*
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* Make note if a temporary relation has been accessed in this
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* transaction.

‎src/test/regress/expected/lock.out

Lines changed: 13 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,10 @@
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CREATE SCHEMA lock_schema1;
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SET search_path = lock_schema1;
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CREATE TABLE lock_tbl1 (a BIGINT);
8-
CREATE VIEW lock_view1 AS SELECT 1;
8+
CREATE VIEW lock_view1 AS SELECT 1 AS a;
9+
CREATE MATERIALIZED VIEW lock_mv1 AS SELECT * FROM lock_view1;
10+
CREATE INDEX lock_mvi1 ON lock_mv1 (a);
11+
CREATE SEQUENCE lock_seq;
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CREATE ROLE regress_rol_lock1;
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ALTER ROLE regress_rol_lock1 SET search_path = lock_schema1;
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GRANT USAGE ON SCHEMA lock_schema1 TO regress_rol_lock1;
@@ -30,8 +33,7 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
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LOCK TABLE lock_tbl1 IN SHARE ROW EXCLUSIVE MODE NOWAIT;
3134
LOCK TABLE lock_tbl1 IN EXCLUSIVE MODE NOWAIT;
3235
LOCK TABLE lock_tbl1 IN ACCESS EXCLUSIVE MODE NOWAIT;
33-
LOCK TABLE lock_view1 IN EXCLUSIVE MODE; -- Will fail; can't lock a non-table
34-
ERROR: "lock_view1" is not a table
36+
LOCK TABLE lock_view1 IN EXCLUSIVE MODE;
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ROLLBACK;
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-- Verify that we can lock a table with inheritance children.
3739
CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);
@@ -51,13 +53,21 @@ BEGIN;
5153
LOCK TABLE ONLY lock_tbl1;
5254
ROLLBACK;
5355
RESET ROLE;
56+
-- Lock other relations
57+
BEGIN TRANSACTION;
58+
LOCK TABLE lock_mv1;
59+
LOCK TABLE lock_mvi1;
60+
LOCK TABLE lock_seq;
61+
ROLLBACK;
5462
--
5563
-- Clean up
5664
--
65+
DROP MATERIALIZED VIEW lock_mv1;
5766
DROP VIEW lock_view1;
5867
DROP TABLE lock_tbl3;
5968
DROP TABLE lock_tbl2;
6069
DROP TABLE lock_tbl1;
70+
DROP SEQUENCE lock_seq;
6171
DROP SCHEMA lock_schema1 CASCADE;
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DROP ROLE regress_rol_lock1;
6373
-- atomic ops tests

‎src/test/regress/sql/lock.sql

Lines changed: 15 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,10 @@
66
CREATESCHEMAlock_schema1;
77
SET search_path= lock_schema1;
88
CREATETABLElock_tbl1 (aBIGINT);
9-
CREATEVIEWlock_view1ASSELECT1;
9+
CREATEVIEWlock_view1ASSELECT1AS a;
10+
CREATE MATERIALIZED VIEW lock_mv1ASSELECT*FROM lock_view1;
11+
CREATEINDEXlock_mvi1ON lock_mv1 (a);
12+
CREATESEQUENCElock_seq;
1013
CREATE ROLE regress_rol_lock1;
1114
ALTER ROLE regress_rol_lock1SET search_path= lock_schema1;
1215
GRANT USAGEON SCHEMA lock_schema1 TO regress_rol_lock1;
@@ -33,7 +36,7 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
3336
LOCK TABLE lock_tbl1IN SHARE ROW EXCLUSIVE MODE NOWAIT;
3437
LOCK TABLE lock_tbl1IN EXCLUSIVE MODE NOWAIT;
3538
LOCK TABLE lock_tbl1IN ACCESS EXCLUSIVE MODE NOWAIT;
36-
LOCK TABLE lock_view1IN EXCLUSIVE MODE;-- Will fail; can't lock a non-table
39+
LOCK TABLE lock_view1IN EXCLUSIVE MODE;
3740
ROLLBACK;
3841

3942
-- Verify that we can lock a table with inheritance children.
@@ -55,13 +58,23 @@ LOCK TABLE ONLY lock_tbl1;
5558
ROLLBACK;
5659
RESET ROLE;
5760

61+
-- Lock other relations
62+
BEGIN TRANSACTION;
63+
LOCK TABLE lock_mv1;
64+
LOCK TABLE lock_mvi1;
65+
LOCK TABLE lock_seq;
66+
ROLLBACK;
67+
68+
5869
--
5970
-- Clean up
6071
--
72+
DROP MATERIALIZED VIEW lock_mv1;
6173
DROPVIEW lock_view1;
6274
DROPTABLE lock_tbl3;
6375
DROPTABLE lock_tbl2;
6476
DROPTABLE lock_tbl1;
77+
DROPSEQUENCE lock_seq;
6578
DROPSCHEMA lock_schema1 CASCADE;
6679
DROP ROLE regress_rol_lock1;
6780

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