Percona XtraDB Storage Engine for MySQL

rw_lock still has possibility to hangup

Reported by Yasufumi Kinoshita on 2009-02-24
2
Affects Status Importance Assigned to Milestone
Percona-XtraDB
Fix Released
High
Unassigned
Percona patches
Fix Released
High
Unassigned

Bug Description

rw_lock implementation may still have possibility to hangup

--Thread 1409067328 has waited at ../../storage/innobase/include/btr0btr.ic line 31 for 7.00 seconds the semaphore:
X-lock on RW-latch at 0x7f1b0bf3cab8 created in file buf/buf0buf.c line 810
a writer (thread id 1409067328) has reserved it in mode wait exclusive
number of readers 0, s_waiters flag 1, x_waiters flag 1
Last time read locked in file not yet reserved line 0
Last time write locked in file btr/btr0cur.c line 467

or

--Thread 1397074240 has waited at btr/btr0cur.c line 418 for 0.00 seconds the semaphore:
S-lock on RW-latch at 0x7f8ef9292138 created in file dict/dict0dict.c line 1541
number of readers 0, s_waiters flag 0, x_waiters flag 0
Last time read locked in file btr/btr0cur.c line 418
Last time write locked in file btr/btr0cur.c line 411

Changed in percona-xtradb:
assignee: nobody → yasufumi-kinoshita
importance: Undecided → High
Changed in percona-patches:
assignee: nobody → yasufumi-kinoshita
importance: Undecided → High
status: New → Confirmed
Changed in percona-xtradb:
status: New → In Progress

~percona-dev/percona-xtradb/fix-rw-lock-set-writer
may be effective to the both of cases.

Changed in percona-xtradb:
status: In Progress → Fix Committed
Changed in percona-xtradb:
status: Fix Committed → In Progress

I don't understand the another possibilities yet.
Hmm...
~percona-dev/percona-xtradb/trial-fix-wait-ex
may be effective, if you still meet the hang.

If this patch is effective, I don't trust behavior of the CPU....

Changed in percona-xtradb:
status: In Progress → Fix Released
Changed in percona-patches:
status: Confirmed → Fix Committed

I should port the stable rw_lock of XtraDB-1.0.3 to percona-patches.

Changed in percona-patches:
status: Fix Committed → In Progress
Changed in percona-patches:
status: In Progress → Fix Committed
Changed in percona-patches:
status: Fix Committed → Fix Released
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