From 91ce16a9035120d41f28f54df28d03d75211287d Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Wed, 4 Nov 2009 12:24:23 +0000
Subject: [PATCH] Allow rewriting ALTER TABLE to skip WAL logging.
Itagaki Takahiro, with small changes by me and Simon.
---
src/backend/commands/tablecmds.c | 38 ++++++++++++++++++++++++++++++--
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 24cbe1dd942..3e0c8191c7e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.304 2009/10/14 22:14:21 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.305 2009/11/04 12:24:23 heikki Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3037,6 +3037,9 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
int i;
ListCell *l;
EState *estate;
+ CommandId mycid;
+ BulkInsertState bistate;
+ int hi_options;
/*
* Open the relation(s). We have surely already locked the existing
@@ -3051,6 +3054,29 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
else
newrel = NULL;
+ /*
+ * Prepare a BulkInsertState and options for heap_insert. Because
+ * we're building a new heap, we can skip WAL-logging and fsync it
+ * to disk at the end instead (unless WAL-logging is required for
+ * archiving). The FSM is empty too, so don't bother using it.
+ */
+ if (newrel)
+ {
+ mycid = GetCurrentCommandId(true);
+ bistate = GetBulkInsertState();
+
+ hi_options = HEAP_INSERT_SKIP_FSM;
+ if (!XLogArchivingActive())
+ hi_options |= HEAP_INSERT_SKIP_WAL;
+ }
+ else
+ {
+ /* keep compiler quiet about using these uninitialized */
+ mycid = 0;
+ bistate = NULL;
+ hi_options = 0;
+ }
+
/*
* If we need to rewrite the table, the operation has to be propagated to
* tables that use this table's rowtype as a column type.
@@ -3252,7 +3278,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
/* Write the tuple out to the new relation */
if (newrel)
- simple_heap_insert(newrel, tuple);
+ heap_insert(newrel, tuple, mycid, hi_options, bistate);
ResetExprContext(econtext);
@@ -3270,7 +3296,15 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
heap_close(oldrel, NoLock);
if (newrel)
+ {
+ FreeBulkInsertState(bistate);
+
+ /* If we skipped writing WAL, then we need to sync the heap. */
+ if (hi_options & HEAP_INSERT_SKIP_WAL)
+ heap_sync(newrel);
+
heap_close(newrel, NoLock);
+ }
}
/*
--
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