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Hi Nick,

its been a while we worked on QC, thus both Andrey and I didn't recall that this behaviour is on purpose. You need to set mysqlnd_qc.cache_no_table to enable caching. 

Assume you have a SQL statement like:

  SELECT some_column, RAND() AS _rand FROM some_table

It is very likely that you do not want this query to be cached. It is likely that your application depends on the random value. Or, think of:

  SELECT some_column, NOW() AS _time FROM some_table
  SELECT SLEEP(1) FROM DUAL

Thus, by default, we do not cache such statements. This feature is not very well documented. However, its mentioned at http://de2.php.net/manual/en/mysqlnd-qc.configuration.php#ini.mysqlnd-qc.cache-no-table .

If mysqlnd_qc.cache_no_table = 0 no query will be cached which has at least one column in its resultset for which MySQL reports no table. In other words a column like "1 AS _one" or "SOME_FUNCTION() AS _func" or "SOME_OTHER_FUNCTION()". There is currently no built-in functionality to set a black or whitelist to refine the behaviour of the global mysqlnd_qc.cache_no_table setting. It should be possible to change behaviour and implement such a feature using an user defined cache handler callback for the cache decision.

Would you like to see some sort of black/whitelisting built-in to the plugin? I assume you would. However, I wouldn't promise it for 1.1 because the old QC code base needs serious refactoring before we add any new features.

Hope that helps!

Ulf