On Tuesday, May 31, 2011 02:14:00 AM Andres Freund wrote:
> On Tuesday, May 31, 2011 01:56:05 AM Cédric Villemain wrote:
> > I remove my own explanations as we conclude on the same thing.
> > Attached is the fix by adding a (!reindex) in the index.c if().
>
> Thats imo wrong because it will break a plain REINDEX?
>
> I think one possible correct fix would be the attached:
My version was wrong as well because it did not observe RelationTruncate's
nblocks argument. That function is used to "shorten" the relation in vacuum.
So dropping the init fork there is not a good idea.
So I think it is the simpler version of simply checking the existance of the
fork before creating is ok.
Andres
From bd7240ab8b331c261d6a5215bee906f8c63f0019 Mon Sep 17 00:00:00 2001
From: Andres Freund <and...@anarazel.de>
Date: Tue, 31 May 2011 02:02:19 +0200
Subject: [PATCH] Fix file existing errors uppon recreation of an unlogged
tables indexes _init fork
The error could only occur if a relation got truncated that got a new
relfilenode in the same transaction before because in that case
heap_truncate_one_rel gets called instead of setting a new relfilenode
for all relevant relations.
To fix that simply check for the existance of the fork before recreating it.
To reproduce:
BEGIN;CREATE UNLOGGED TABLE foo (a int PRIMARY KEY);TRUNCATE foo; ROLLBACK;
---
src/backend/catalog/index.c | 3 ++-
src/backend/catalog/storage.c | 2 --
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index a0898e0..d833a09 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1743,7 +1743,8 @@ index_build(Relation heapRelation,
/*
* If this is an unlogged index, we need to write out an init fork for it.
*/
- if (heapRelation->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED)
+ if (heapRelation->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED
+ && !smgrexists(indexRelation->rd_smgr, FSM_FORKNUM))
{
RegProcedure ambuildempty = indexRelation->rd_am->ambuildempty;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 57987be..68a7b30 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -265,8 +265,6 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
/* Truncate the FSM first if it exists */
fsm = smgrexists(rel->rd_smgr, FSM_FORKNUM);
- if (fsm)
- FreeSpaceMapTruncateRel(rel, nblocks);
/* Truncate the visibility map too if it exists. */
vm = smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
--
1.7.5.rc1.16.g9db1.dirty
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