Comment 6 for bug 791030

* On Tue, Dec 11, 2012 at 07:18:42AM -0000, vineet khanna <email address hidden> wrote:
>Hi,
>
>I am having
>
>mysql> show variables like 'innodb_adaptive_hash_index_partitions';
>+---------------------------------------+-------+
>| Variable_name | Value |
>+---------------------------------------+-------+
>| innodb_adaptive_hash_index_partitions | 1 |
>+---------------------------------------+-------+
>
>Still i am getting SEMAPHORES issue:
>
>----------
>SEMAPHORES
>----------
>OS WAIT ARRAY INFO: reservation count 4641988, signal count 327450531
>--Thread 1219737920 has waited at row0sel.c line 3698 for 0.0000 seconds the semaphore:
>S-lock on RW-latch at 0x29ea4b18 'btr_search_latch_part[i]'
>number of readers 0, waiters flag 0, lock_word: 100000
>Last time read locked in file btr0sea.c line 918
>Last time write locked in file /home/jenkins/workspace/percona-server-5.5-rpms/label_exp/centos5-64/target/BUILD/Percona-Server-5.5.22-rel25.2/Percona-Server-5.5.22-rel25.2/storage/innobase/btr/btr0sea.c line 669
>--Thread 1218406720 has waited at btr0sea.c line 1508 for 0.0000 seconds the semaphore:
>S-lock on RW-latch at 0x29ea4b18 'btr_search_latch_part[i]'
>number of readers 0, waiters flag 0, lock_word: 100000
>Last time read locked in file btr0sea.c line 918
>Last time write locked in file /home/jenkins/workspace/percona-server-5.5-rpms/label_exp/centos5-64/target/BUILD/Percona-Server-5.5.22-rel25.2/Percona-Server-5.5.22-rel25.2/storage/innobase/btr/btr0sea.c line 669
>--Thread 1219205440 has waited at btr0sea.c line 1508 for 0.0000 seconds the semaphore:
>S-lock on RW-latch at 0x29ea4b18 'btr_search_latch_part[i]'
>number of readers 0, waiters flag 0, lock_word: 100000
>Last time read locked in file btr0sea.c line 918
>
>
>Please update if its a same issue.
>
It is not, in your case, setting
innodb_adaptive_hash_index_partitions to non-default value (say
8) should ameliorate your issue.

The lp issue is about circular lock deadlock like for
139558755972864 in comment#3.