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Flag index metapages as standard-format in xlog.c calls.

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btree, hash, and bloom indexes all set up their metapages in standard
format (that is, with pd_lower and pd_upper correctly delimiting the
unused area); but they mostly didn't inform the xlog routines of this.
When calling log_newpage[_buffer], this is bad because it loses the
opportunity to compress unused data out of the WAL record.  When
calling XLogRegisterBuffer, it's not such a performance problem because
all of these call sites also use REGBUF_WILL_INIT, preventing an FPI
image from being written.  But it's still a good idea to provide the
flag when relevant, because that aids WAL consistency checking.

This completes the project of getting all the in-core index AMs to
handle their metapage WAL operations similarly.

Amit Kapila, reviewed by Michael Paquier

Discussion: https://postgr.es/m/0d273805-0e9e-ec1a-cb84-d4da400b8f85@lab.ntt.co.jp
This commit is contained in:
Tom Lane
2017-11-03 16:31:32 -04:00
parent 1b890562b8
commit 4c11d2c559
6 changed files with 16 additions and 13 deletions
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7
src/backend/access/hash/hashpage.c
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@@ -403,7 +403,7 @@ _hash_init(Relation rel, double num_tuples, ForkNumber forkNum)
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, SizeOfHashInitMetaPage);
XLogRegisterBuffer(0, metabuf, REGBUF_WILL_INIT);
XLogRegisterBuffer(0, metabuf, REGBUF_WILL_INIT | REGBUF_STANDARD);
recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_INIT_META_PAGE);
@@ -592,8 +592,9 @@ _hash_init_metabuffer(Buffer buf, double num_tuples, RegProcedure procid,
metap->hashm_firstfree = 0;
/*
* Set pd_lower just past the end of the metadata. This is to log full
* page image of metapage in xloginsert.c.
* Set pd_lower just past the end of the metadata. This is essential,
* because without doing so, metadata will be lost if xlog.c compresses
* the page.
*/
((PageHeader) page)->pd_lower =
((char *) metap + sizeof(HashMetaPageData)) - (char *) page;