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Make DDL operations play nicely with Serializable Snapshot Isolation.

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Truncating or dropping a table is treated like deletion of all tuples, and
check for conflicts accordingly. If a table is clustered or rewritten by
ALTER TABLE, all predicate locks on the heap are promoted to relation-level
locks, because the tuple or page ids of any existing tuples will change and
won't be valid after rewriting the table. Arguably ALTER TABLE should be
treated like a mass-UPDATE of every row, but if you e.g change the datatype
of a column, you could also argue that it's just a change to the physical
layout, not a logical change. Reindexing promotes all locks on the index to
relation-level lock on the heap.

Kevin Grittner, with a lot of cosmetic changes by me.
This commit is contained in:
Heikki Linnakangas
2011-06-08 13:47:21 +03:00
parent 16925c1e1f
commit 8f9622bbb3
7 changed files with 499 additions and 80 deletions
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9
src/backend/commands/cluster.c
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@ -39,6 +39,7 @@
#include "optimizer/planner.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/predicate.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
#include "utils/acl.h"
@ -385,6 +386,14 @@ cluster_rel(Oid tableOid, Oid indexOid, bool recheck, bool verbose,
if (OidIsValid(indexOid))
check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
/*
* All predicate locks on the tuples or pages are about to be made
* invalid, because we move tuples around. Promote them to relation
* locks. Predicate locks on indexes will be promoted when they are
* reindexed.
*/
TransferPredicateLocksToHeapRelation(OldHeap);
/* rebuild_relation does all the dirty work */
rebuild_relation(OldHeap, indexOid, freeze_min_age, freeze_table_age,
verbose);