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Further work on connecting the free space map (which is still just a

stub) into the rest of the system. Adopt a cleaner approach to preventingdeadlock in concurrent heap_updates: allow RelationGetBufferForTuple toselect any page of the rel, and put the onus on it to lock both buffersin a consistent order. Remove no-longer-needed isExtend hack fromAPI of ReleaseAndReadBuffer.

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12 files changed

+379

-231

lines changed

src
- backend
  - access
    - heap
      - heapam.c
      - hio.c
    - transam
      - xlogutils.c
  - catalog
    - heap.c
  - commands
    - sequence.c
  - storage
    - buffer
      - bufmgr.c
    - freespace
      - freespace.c
    - smgr
      - smgr.c
  - utils/cache
    - relcache.c
- include
  - access
    - hio.h
  - storage
    - bufmgr.h
  - utils
    - relcache.h

12 files changed

+379

-231

lines changed

`‎src/backend/access/heap/heapam.c‎`

Lines changed: 14 additions & 20 deletions

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.120 2001/06/27 23:31:38 tgl Exp $`
	`11`	`+ * $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.121 2001/06/29 21:08:23 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*`
`14`	`14`	`* INTERFACE ROUTINES`
`@@ -202,8 +202,7 @@ heapgettup(Relation relation,`
`202`	`202`
`203`	`203`	`buffer=ReleaseAndReadBuffer(buffer,`
`204`	`204`	`relation,`
`205`		`-ItemPointerGetBlockNumber(tid),`
`206`		`- false);`
	`205`	`+ItemPointerGetBlockNumber(tid));`
`207`	`206`	`if (!BufferIsValid(*buffer))`
`208`	`207`	`elog(ERROR,"heapgettup: failed ReadBuffer");`
`209`	`208`
`@@ -238,8 +237,7 @@ heapgettup(Relation relation,`
`238`	`237`
`239`	`238`	`buffer=ReleaseAndReadBuffer(buffer,`
`240`	`239`	`relation,`
`241`		`-page,`
`242`		`- false);`
	`240`	`+page);`
`243`	`241`	`if (!BufferIsValid(*buffer))`
`244`	`242`	`elog(ERROR,"heapgettup: failed ReadBuffer");`
`245`	`243`
`@@ -280,8 +278,7 @@ heapgettup(Relation relation,`
`280`	`278`
`281`	`279`	`buffer=ReleaseAndReadBuffer(buffer,`
`282`	`280`	`relation,`
`283`		`-page,`
`284`		`- false);`
	`281`	`+page);`
`285`	`282`	`if (!BufferIsValid(*buffer))`
`286`	`283`	`elog(ERROR,"heapgettup: failed ReadBuffer");`
`287`	`284`
`@@ -374,8 +371,7 @@ heapgettup(Relation relation,`
`374`	`371`
`375`	`372`	`buffer=ReleaseAndReadBuffer(buffer,`
`376`	`373`	`relation,`
`377`		`-page,`
`378`		`- false);`
	`374`	`+page);`
`379`	`375`	`if (!BufferIsValid(*buffer))`
`380`	`376`	`elog(ERROR,"heapgettup: failed ReadBuffer");`
`381`	`377`
`@@ -1088,8 +1084,8 @@ heap_insert(Relation relation, HeapTuple tup)`
`1088`	`1084`	`heap_tuple_toast_attrs(relation,tup,NULL);`
`1089`	`1085`	`#endif`
`1090`	`1086`
`1091`		`-/* Find bufferforthis tuple */`
`1092`		`-buffer=RelationGetBufferForTuple(relation,tup->t_len,0);`
	`1087`	`+/* Find bufferto insertthis tuple into */`
	`1088`	`+buffer=RelationGetBufferForTuple(relation,tup->t_len,InvalidBuffer);`
`1093`	`1089`
`1094`	`1090`	`/* NO ELOG(ERROR) from here till changes are logged */`
`1095`	`1091`	`START_CRIT_SECTION();`
`@@ -1501,18 +1497,16 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,`
`1501`	`1497`	`* buffer locks on both old and new pages. To avoid deadlock against`
`1502`	`1498`	`* some other backend trying to get the same two locks in the other`
`1503`	`1499`	`* order, we must be consistent about the order we get the locks in.`
`1504`		`- * We use the rule "lock thehigher-numbered page of the relation`
	`1500`	`+ * We use the rule "lock thelower-numbered page of the relation`
`1505`	`1501`	`* first". To implement this, we must do RelationGetBufferForTuple`
`1506`		`- * while not holding the lock on the old page, and we musttell it`
`1507`		`- * togive us a page beyondtheold page.`
	`1502`	`+ * while not holding the lock on the old page, and we mustrely on it`
	`1503`	`+ * toget the locks on both pages inthecorrect order.`
`1508`	`1504`	`*/`
`1509`	`1505`	`if (newtupsize>pagefree)`
`1510`	`1506`	`{`
`1511`	`1507`	`/* Assume there's no chance to put newtup on same page. */`
`1512`	`1508`	`newbuf=RelationGetBufferForTuple(relation,newtup->t_len,`
`1513`		`-BufferGetBlockNumber(buffer)+1);`
`1514`		`-/* Now reacquire lock on old tuple's page. */`
`1515`		`-LockBuffer(buffer,BUFFER_LOCK_EXCLUSIVE);`
	`1509`	`+buffer);`
`1516`	`1510`	`}`
`1517`	`1511`	`else`
`1518`	`1512`	`{`
`@@ -1529,8 +1523,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,`
`1529`	`1523`	`*/`
`1530`	`1524`	`LockBuffer(buffer,BUFFER_LOCK_UNLOCK);`
`1531`	`1525`	`newbuf=RelationGetBufferForTuple(relation,newtup->t_len,`
`1532`		`-BufferGetBlockNumber(buffer)+1);`
`1533`		`-LockBuffer(buffer,BUFFER_LOCK_EXCLUSIVE);`
	`1526`	`+buffer);`
`1534`	`1527`	`}`
`1535`	`1528`	`else`
`1536`	`1529`	`{`
`@@ -1550,7 +1543,8 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,`
`1550`	`1543`
`1551`	`1544`	`/*`
`1552`	`1545`	`* At this point newbuf and buffer are both pinned and locked,`
`1553`		`- * and newbuf has enough space for the new tuple.`
	`1546`	`+ * and newbuf has enough space for the new tuple. If they are`
	`1547`	`+ * the same buffer, only one pin is held.`
`1554`	`1548`	`*/`
`1555`	`1549`
`1556`	`1550`	`/* NO ELOG(ERROR) from here till changes are logged */`

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Commitaf5ced9

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12 files changed

12 files changed

`‎src/backend/access/heap/heapam.c‎`

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