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Change CRCs in WAL records from 64bit to 32bit for performance reasons.

Instead of a separate CRC on each backup block, include backup blocksin their parent WAL record's CRC; this is important to ensure that thebackup block really goes with the WAL record, ie there was not a pagetear right at the start of the backup block. Implement a simple formof compression of backup blocks: drop any run of zeroes starting atpd_lower, so as not to store the unused 'hole' that commonly exists inPG heap and index pages. Tweak PageRepairFragmentation and relatedroutines to ensure they keep the unused space zeroed, so that the abovecompression method remains effective. All per recent discussions.

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11 files changed

+511

-207

lines changed

src
- backend
  - access
    - nbtree
      - nbtpage.c
      - nbtxlog.c
    - transam
      - xlog.c
  - storage/page
    - bufpage.c
  - utils/hash
    - pg_crc.c
- bin
  - pg_controldata
    - pg_controldata.c
  - pg_resetxlog
    - pg_resetxlog.c
- include
  - access
    - xlog.h
    - xlog_internal.h
  - catalog
    - pg_control.h
  - utils
    - pg_crc.h

11 files changed

+511

-207

lines changed

`‎src/backend/access/nbtree/nbtpage.c`

Lines changed: 8 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -9,7 +9,7 @@`
`9`	`9`	`*`
`10`	`10`	`*`
`11`	`11`	`* IDENTIFICATION`
`12`		`- * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.84 2005/05/07 21:32:23 tgl Exp $`
	`12`	`+ * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.85 2005/06/02 05:55:28 tgl Exp $`
`13`	`13`	`*`
`14`	`14`	`*NOTES`
`15`	`15`	`* Postgres btree pages look like ordinary relation pages.The opaque`
`@@ -113,6 +113,13 @@ _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level)`
`113`	`113`
`114`	`114`	`metaopaque= (BTPageOpaque)PageGetSpecialPointer(page);`
`115`	`115`	`metaopaque->btpo_flags=BTP_META;`
	`116`	`+`
	`117`	`+/*`
	`118`	`+ * Set pd_lower just past the end of the metadata. This is not`
	`119`	`+ * essential but it makes the page look compressible to xlog.c.`
	`120`	`+ */`
	`121`	`+((PageHeader)page)->pd_lower=`
	`122`	`+((char)metad+sizeof(BTMetaPageData))- (char)page;`
`116`	`123`	`}`
`117`	`124`
`118`	`125`	`/*`

`‎src/backend/access/nbtree/nbtxlog.c`

Lines changed: 8 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`* Portions Copyright (c) 1994, Regents of the University of California`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.20 2005/03/22 06:17:03 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.21 2005/06/02 05:55:28 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -135,6 +135,13 @@ _bt_restore_meta(Relation reln, XLogRecPtr lsn,`
`135`	`135`	`pageop= (BTPageOpaque)PageGetSpecialPointer(metapg);`
`136`	`136`	`pageop->btpo_flags=BTP_META;`
`137`	`137`
	`138`	`+/*`
	`139`	`+ * Set pd_lower just past the end of the metadata. This is not`
	`140`	`+ * essential but it makes the page look compressible to xlog.c.`
	`141`	`+ */`
	`142`	`+((PageHeader)metapg)->pd_lower=`
	`143`	`+((char)md+sizeof(BTMetaPageData))- (char)metapg;`
	`144`	`+`
`138`	`145`	`PageSetLSN(metapg,lsn);`
`139`	`146`	`PageSetTLI(metapg,ThisTimeLineID);`
`140`	`147`	`LockBuffer(metabuf,BUFFER_LOCK_UNLOCK);`

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Commit21fda22

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11 files changed

11 files changed

`‎src/backend/access/nbtree/nbtpage.c`

`‎src/backend/access/nbtree/nbtxlog.c`

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