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Log the creation of an init fork unconditionally.

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Previously, it was thought that this only needed to be done for the
benefit of possible standbys, so wal_level = minimal skipped it.
But that's not safe, because during crash recovery we might replay
XLOG_DBASE_CREATE or XLOG_TBLSPC_CREATE record which recursively
removes the directory that contains the new init fork.  So log it
always.

The user-visible effect of this bug is that if you create a database
or tablespace, then create an unlogged table, then crash without
checkpointing, then restart, accessing the table will fail, because
the it won't have been properly reset.  This commit fixes that.

Michael Paquier, per a report from Konstantin Knizhnik.  Wording of
the comments per a suggestion from me.
This commit is contained in:
Robert Haas
2016-12-08 14:09:09 -05:00
parent 0b78106cd4
commit fa0f466d53
4 changed files with 38 additions and 24 deletions
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13
contrib/bloom/blinsert.c
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@ -164,13 +164,18 @@ blbuildempty(Relation index)
metapage = (Page) palloc(BLCKSZ);
BloomFillMetapage(index, metapage);
/* Write the page. If archiving/streaming, XLOG it. */
/*
* Write the page and log it. It might seem that an immediate sync
* would be sufficient to guarantee that the file exists on disk, but
* recovery itself might remove it while replaying, for example, an
* XLOG_DBASE_CREATE or XLOG_TBLSPC_CREATE record. Therefore, we
* need this even when wal_level=minimal.
*/
PageSetChecksumInplace(metapage, BLOOM_METAPAGE_BLKNO);
smgrwrite(index->rd_smgr, INIT_FORKNUM, BLOOM_METAPAGE_BLKNO,
(char *) metapage, true);
if (XLogIsNeeded())
log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
BLOOM_METAPAGE_BLKNO, metapage, false);
log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
BLOOM_METAPAGE_BLKNO, metapage, false);
/*
* An immediate sync is required even if we xlog'd the page, because the