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| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2011-06-08 13:47:21 +0300 |
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| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2011-06-08 14:02:43 +0300 |
| commit | 8f9622bbb3c02b06176760c3ca2d33c5b5f629a7 (patch) | |
| tree | 28aa06c755c12951e7c99f11815a9379ba3c76d3 /src/backend/commands/tablecmds.c | |
| parent | 16925c1e1fa236e4d7d6c8b571890e7c777f75d7 (diff) | |
| download | postgresql-8f9622bbb3c02b06176760c3ca2d33c5b5f629a7.tar.gz postgresql-8f9622bbb3c02b06176760c3ca2d33c5b5f629a7.zip | |
Make DDL operations play nicely with Serializable Snapshot Isolation.
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.
Diffstat (limited to 'src/backend/commands/tablecmds.c')
| -rw-r--r-- | src/backend/commands/tablecmds.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 60b66ec5c5f..6279f2bf9a5 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -70,6 +70,7 @@ #include "storage/bufmgr.h" #include "storage/lmgr.h" #include "storage/lock.h" +#include "storage/predicate.h" #include "storage/smgr.h" #include "utils/acl.h" #include "utils/builtins.h" @@ -1040,6 +1041,14 @@ ExecuteTruncate(TruncateStmt *stmt) Oid toast_relid; /* + * This effectively deletes all rows in the table, and may be done + * in a serializable transaction. In that case we must record a + * rw-conflict in to this transaction from each transaction + * holding a predicate lock on the table. + */ + CheckTableForSerializableConflictIn(rel); + + /* * Need the full transaction-safe pushups. * * Create a new empty storage file for the relation, and assign it @@ -3529,6 +3538,16 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode) (errmsg("verifying table \"%s\"", RelationGetRelationName(oldrel)))); + if (newrel) + { + /* + * All predicate locks on the tuples or pages are about to be made + * invalid, because we move tuples around. Promote them to + * relation locks. + */ + TransferPredicateLocksToHeapRelation(oldrel); + } + econtext = GetPerTupleExprContext(estate); /* |