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Fix relcache handling of the 'default' partition

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My commit 4dba331cb3 that moved around CommandCounterIncrement calls
in partitioning DDL code unearthed a problem with the relcache handling
for the 'default' partition: the construction of a correct relcache
entry for the partitioned table was at the mercy of lack of CCI calls in
non-trivial amounts of code.  This was prone to creating problems later
on, as the code develops.  This was visible as a test failure in a
compile with RELCACHE_FORCE_RELASE (buildfarm member prion).

The problem is that after the mentioned commit it was possible to create
a relcache entry that had incomplete information regarding the default
partition because I introduced a CCI between adding the catalog entries
for the default partition (StorePartitionBound) and the update of
pg_partitioned_table entry for its parent partitioned table
(update_default_partition_oid).  It seems the best fix is to move the
latter so that it occurs inside the former; the purposeful lack of
intervening CCI should be more obvious, and harder to break.

I also remove a check in RelationBuildPartitionDesc that returns NULL if
the key is not set.  I couldn't find any place that needs this hack
anymore; probably it was required because of bugs that have since been
fixed.

Fix a few typos I noticed while reviewing the code involved.

Discussion: https://postgr.es/m/20180320182659.nyzn3vqtjbbtfgwq@alvherre.pgsql
This commit is contained in:
Alvaro Herrera
2018-03-21 12:03:35 -03:00
parent e51a04840a
commit 56163004b8
3 changed files with 21 additions and 27 deletions
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25
src/backend/commands/tablecmds.c
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@ -860,10 +860,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
/* Update the pg_class entry. */
StorePartitionBound(rel, parent, bound);
/* Update the default partition oid */
if (bound->is_default)
update_default_partition_oid(RelationGetRelid(parent), relationId);
heap_close(parent, NoLock);
}
@ -14021,11 +14017,6 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
/* OK to create inheritance. Rest of the checks performed there */
CreateInheritance(attachrel, rel);
/* Update the default partition oid */
if (cmd->bound->is_default)
update_default_partition_oid(RelationGetRelid(rel),
RelationGetRelid(attachrel));
/*
* Check that the new partition's bound is valid and does not overlap any
* of existing partitions of the parent - note that it does not return on
@ -14286,7 +14277,7 @@ ATExecDetachPartition(Relation rel, RangeVar *name)
/*
* We must lock the default partition, because detaching this partition
* will changing its partition constrant.
* will change its partition constraint.
*/
defaultPartOid =
get_default_oid_from_partdesc(RelationGetPartitionDesc(rel));
@ -14329,19 +14320,17 @@ ATExecDetachPartition(Relation rel, RangeVar *name)
if (OidIsValid(defaultPartOid))
{
/*
* If the detach relation is the default partition itself, invalidate
* its entry in pg_partitioned_table.
* If the relation being detached is the default partition itself,
* remove it from the parent's pg_partitioned_table entry.
*
* If not, we must invalidate default partition's relcache entry, as
* in StorePartitionBound: its partition constraint depends on every
* other partition's partition constraint.
*/
if (RelationGetRelid(partRel) == defaultPartOid)
update_default_partition_oid(RelationGetRelid(rel), InvalidOid);
else
{
/*
* We must invalidate default partition's relcache, for the same
* reasons explained in StorePartitionBound().
*/
CacheInvalidateRelcacheByRelid(defaultPartOid);
}
}
/* detach indexes too */