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Accept relations of any kind in LOCK TABLE

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The restriction that only tables and views can be locked by LOCK TABLE
is quite arbitrary, since the underlying mechanism can lock any relation
type.  Drop the restriction so that programs such as pg_dump can lock
all relations they're interested in, preventing schema changes that
could 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
This commit is contained in:
Alvaro Herrera
2020-10-27 13:49:19 -03:00
parent 4066b64290
commit 59ab4ac324
4 changed files with 42 additions and 25 deletions
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28
src/backend/commands/lockcmds.c
View File

@ -83,14 +83,6 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
return; /* woops, concurrently dropped; no permissions
* check */
/* Currently, we only allow plain tables or views to be locked */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
rv->relname)));
/*
* Make note if a temporary relation has been accessed in this
* transaction.
@ -186,11 +178,13 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
foreach(rtable, query->rtable)
{
RangeTblEntry *rte = lfirst(rtable);
Oid relid;
AclResult aclresult;
Oid relid = rte->relid;
char relkind = rte->relkind;
char *relname = get_rel_name(relid);
/* ignore all non-relation RTEs */
if (rte->rtekind != RTE_RELATION)
continue;
relid = rte->relid;
/*
* The OLD and NEW placeholder entries in the view's rtable are
@ -201,11 +195,6 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
strcmp(rte->eref->aliasname, "new") == 0))
continue;
/* Currently, we only allow plain tables or views to be locked. */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
relkind != RELKIND_VIEW)
continue;
/* Check infinite recursion in the view definition. */
if (list_member_oid(context->ancestor_views, relid))
ereport(ERROR,
@ -216,7 +205,8 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
/* Check permissions with the view owner's privilege. */
aclresult = LockTableAclCheck(relid, context->lockmode, context->viewowner);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(relkind), relname);
aclcheck_error(aclresult, get_relkind_objtype(rte->relkind),
get_rel_name(relid));
/* We have enough rights to lock the relation; do so. */
if (!context->nowait)
@ -225,9 +215,9 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on relation \"%s\"",
relname)));
get_rel_name(relid))));
if (relkind == RELKIND_VIEW)
if (rte->relkind == RELKIND_VIEW)
LockViewRecurse(relid, context->lockmode, context->nowait, context->ancestor_views);
else if (rte->inh)
LockTableRecurse(relid, context->lockmode, context->nowait);