Re: INSERT/UPDATE within transactions (autocommit=0)

[Rick James]

I'm confused:
"INSERT DELAYED works only with MyISAM, MEMORY, ARCHIVE, and (as of MySQL 5.1.19) BLACKHOLE tables. For engines that do not support DELAYED, an error occurs. " -- http://dev.mysql.com/doc/refman/5.1/en/insert-delayed.html
yet you are using it on an InnoDB table??

query_cache_size | 536870912 -- this may be excessive. The reason? Some actions on the QC are take linear time, thereby run slower when the QC is bigger.

Sounds like the QC is quite inefficient:

| Qcache_hits                       | 124848796   |
| Qcache_inserts                    | 74927607    |

Remember, _any_ change (INSERT, etc) to a table will invalidate _all_ entries in the QC for that table. The bigger the QC, the longer this takes. And, any table that is frequently written to will have little use for the QC.

Sorry, I have no feel for FLUSH QUERY CACHE.

Lost connection -- Increase the GLOBAL versions of wait_timeout and interactive_wait_timeout. _Maybe_ that will help.

SHOW STATUS; -- useless because it only applies to the current session. SHOW GLOBAL STATUS; is more useful. (OK, QC values will be the same in both, but Aborted_connections may not.)