Commit3e5ea47

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Stop reading uninitialized memory in heap_inplace_lock().

Stop computing a never-used value. This removes the read; the read hadno functional implications. Back-patch to v12, like commita07e03f.Reported by Alexander Lakhin.Discussion:https://postgr.es/m/6c92f59b-f5bc-e58c-9bdd-d1f21c17c786@gmail.com

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+33

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Lines changed: 1 addition & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -6038,10 +6038,9 @@ heap_inplace_lock(Relation relation,`
`6038`	`6038`	`LockTupleModelockmode=LockTupleNoKeyExclusive;`
`6039`	`6039`	`MultiXactStatusmxact_status=MultiXactStatusNoKeyUpdate;`
`6040`	`6040`	`intremain;`
`6041`		`-boolcurrent_is_member;`
`6042`	`6041`
`6043`	`6042`	`if (DoesMultiXactIdConflict((MultiXactId)xwait,infomask,`
`6044`		`-lockmode,&current_is_member))`
	`6043`	`+lockmode,NULL))`
`6045`	`6044`	`{`
`6046`	`6045`	`LockBuffer(buffer,BUFFER_LOCK_UNLOCK);`
`6047`	`6046`	`ret= false;`

Lines changed: 24 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -63,6 +63,30 @@ step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>`
`63`	`63`	`step r3: ROLLBACK;`
`64`	`64`	`step addk2: <... completed>`
`65`	`65`
	`66`	`+starting permutation: b3 sfnku3 keyshr5 addk2 r3`
	`67`	`+step b3: BEGIN ISOLATION LEVEL READ COMMITTED;`
	`68`	`+step sfnku3:`
	`69`	`+SELECT relhasindex FROM pg_class`
	`70`	`+WHERE oid = 'intra_grant_inplace'::regclass FOR NO KEY UPDATE;`
	`71`	`+`
	`72`	`+relhasindex`
	`73`	`+-----------`
	`74`	`+f`
	`75`	`+(1 row)`
	`76`	`+`
	`77`	`+step keyshr5:`
	`78`	`+SELECT relhasindex FROM pg_class`
	`79`	`+WHERE oid = 'intra_grant_inplace'::regclass FOR KEY SHARE;`
	`80`	`+`
	`81`	`+relhasindex`
	`82`	`+-----------`
	`83`	`+f`
	`84`	`+(1 row)`
	`85`	`+`
	`86`	`+step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>`
	`87`	`+step r3: ROLLBACK;`
	`88`	`+step addk2: <... completed>`
	`89`	`+`
`66`	`90`	`starting permutation: b2 sfnku2 addk2 c2`
`67`	`91`	`step b2: BEGIN;`
`68`	`92`	`step sfnku2:`

Lines changed: 8 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -96,6 +96,14 @@ permutation`
`96`	`96`	`addk2(r3)`
`97`	`97`	`r3`
`98`	`98`
	`99`	`+# reproduce bug in DoesMultiXactIdConflict() call`
	`100`	`+permutation`
	`101`	`+b3`
	`102`	`+sfnku3`
	`103`	`+keyshr5`
	`104`	`+addk2(r3)`
	`105`	`+r3`
	`106`	`+`
`99`	`107`	`# same-xact rowmark`
`100`	`108`	`permutation`
`101`	`109`	`b2`

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