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Used optimized linear search in more code paths

This commit updates two code paths to use pg_lfind32() introduced byb6ef167 with TransactionId arrays:- At the end of TransactionIdIsInProgress(), when checking for the caseof still running but overflowed subxids.- XidIsConcurrent(), when checking for a serializable conflict.These cases are less impactful than37a6e5d, but a bit ofmicro-benchmarking of this API shows that linear search speeds up by~20% depending on the number of items involved (x86_64 and amd64 lookedat here).Author: Nathan BossartReviewed-by: Richard Guo, Michael PaquierDiscussion:https://postgr.es/m/20220901185153.GA783106@nathanxps13

1 parent9a69152 commit14ff44fCopy full SHA for 14ff44f

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2 files changed

-16

lines changed

src/backend/storage
- ipc
  - procarray.c
- lmgr
  - predicate.c

2 files changed

-16

lines changed

`‎src/backend/storage/ipc/procarray.c`

Lines changed: 4 additions & 8 deletions

Original file line number	Diff line number	Diff line change
`@@ -58,6 +58,7 @@`
`58`	`58`	`#include"commands/dbcommands.h"`
`59`	`59`	`#include"miscadmin.h"`
`60`	`60`	`#include"pgstat.h"`
	`61`	`+#include"port/pg_lfind.h"`
`61`	`62`	`#include"storage/proc.h"`
`62`	`63`	`#include"storage/procarray.h"`
`63`	`64`	`#include"storage/spin.h"`
`@@ -1586,14 +1587,9 @@ TransactionIdIsInProgress(TransactionId xid)`
`1586`	`1587`	`*/`
`1587`	`1588`	`topxid=SubTransGetTopmostTransaction(xid);`
`1588`	`1589`	`Assert(TransactionIdIsValid(topxid));`
`1589`		`-if (!TransactionIdEquals(topxid,xid))`
`1590`		`-{`
`1591`		`-for (inti=0;i<nxids;i++)`
`1592`		`-{`
`1593`		`-if (TransactionIdEquals(xids[i],topxid))`
`1594`		`-return true;`
`1595`		`-}`
`1596`		`-}`
	`1590`	`+if (!TransactionIdEquals(topxid,xid)&&`
	`1591`	`+pg_lfind32(topxid,xids,nxids))`
	`1592`	`+return true;`
`1597`	`1593`
`1598`	`1594`	`cachedXidIsNotInProgress=xid;`
`1599`	`1595`	`return false;`

`‎src/backend/storage/lmgr/predicate.c`

Lines changed: 2 additions & 8 deletions

Original file line number	Diff line number	Diff line change
`@@ -202,6 +202,7 @@`
`202`	`202`	`#include"access/xlog.h"`
`203`	`203`	`#include"miscadmin.h"`
`204`	`204`	`#include"pgstat.h"`
	`205`	`+#include"port/pg_lfind.h"`
`205`	`206`	`#include"storage/bufmgr.h"`
`206`	`207`	`#include"storage/predicate.h"`
`207`	`208`	`#include"storage/predicate_internals.h"`
`@@ -4065,7 +4066,6 @@ static bool`
`4065`	`4066`	`XidIsConcurrent(TransactionIdxid)`
`4066`	`4067`	`{`
`4067`	`4068`	`Snapshotsnap;`
`4068`		`-uint32i;`
`4069`	`4069`
`4070`	`4070`	`Assert(TransactionIdIsValid(xid));`
`4071`	`4071`	`Assert(!TransactionIdEquals(xid,GetTopTransactionIdIfAny()));`
`@@ -4078,13 +4078,7 @@ XidIsConcurrent(TransactionId xid)`
`4078`	`4078`	`if (TransactionIdFollowsOrEquals(xid,snap->xmax))`
`4079`	`4079`	`return true;`
`4080`	`4080`
`4081`		`-for (i=0;i<snap->xcnt;i++)`
`4082`		`-{`
`4083`		`-if (xid==snap->xip[i])`
`4084`		`-return true;`
`4085`		`-}`
`4086`		`-`
`4087`		`-return false;`
	`4081`	`+returnpg_lfind32(xid,snap->xip,snap->xcnt);`
`4088`	`4082`	`}`
`4089`	`4083`
`4090`	`4084`	`bool`

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Commit14ff44f

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2 files changed

2 files changed

`‎src/backend/storage/ipc/procarray.c`

`‎src/backend/storage/lmgr/predicate.c`

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