PDOException Deadlock

Question

Yesterday I had a peek in visitors and I saw following PDOException in my logs:

PDOException: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction: SELECT revision.order_number AS order_number, revision.revision_id AS revision_id, revision.revision_uid AS revision_uid, revision.mail AS mail, revision.status AS status, revision.log AS log, revision.revision_timestamp AS revision_timestamp, revision.revision_hostname AS revision_hostname, revision.data AS data, base.order_id AS order_id, base.type AS type, base.uid AS uid, base.created AS created, base.changed AS changed, base.hostname AS hostname FROM {commerce_order} base INNER JOIN {commerce_order_revision} revision ON revision.revision_id = base.revision_id WHERE (base.order_id IN (:db_condition_placeholder_0)) FOR UPDATE; Array ( [:db_condition_placeholder_0] => 6131 ) in DrupalDefaultEntityController->load() (line 191 of /var/www/vhosts/shopmybooks.com/releases/20141208090103/web/includes/entity.inc).

I can't seem to find any good solution for this. Drupal version 7.27

Any help?

Answer 1

I had some similiar issue.

Problem was that drupal was cosuming 100% of cpu usage, sometimes making the execution of some queries to take to long and reaching the max timeout on LOCK_TIMEOUT

If you have acccess to command line, check proccess, cpu usages, sql usage and so on

Hope it helps

There are some threads about drupal sites cosuming 100% of cpu (Kind of old but i had this problem recently), take a look

See this thread for a bit of debuging

Answer 2

We had a similar issue with the revisioning module over 18 months ago.

At the time there were bug reports on the revisioning module misbehaving and this resulting on server crashes. (See bug reports here and here.)

Unable to find a reasonable solution we did away with the problem by disabling the revisioning module. The crashes went away too. And we never got to the question because lack of time.

Since your error message points to the revision table I though this might be related to our past problems.

So, consider if you can do without the revisioning module as a quick solution.

Else, see if you can update the module to a more recent version. That may help too.

Good luck.