Hi all, With all the talking about caching I would like to ask some things. Currently I am using MyISAM tables. I have a small moodle site and was puzzled about the amount of memory being used. Tinkered with apache and enabled the mysql query_cache. The last tweak, the cache, is a MySQL only thing, PostgreSQL does not use it. Running the site a few days I kept wondering why it still does not really speed up. I think I now found part of the problem. There are some tables that are unfit to be used with the query cache. This is not due to drupal but more to the specifics the query cache is using. MySQL will optimize queries and will store select queries, when possible, in the cache. There for it does not need to recompile/optimize the query the next time it is called. Whenever a value is updated or inserted in a table the queries that are questioning these tables will be invalidated. For a few Drupal tables this will only generate extra cpu cycles without any benefit. Both the session and cache tables are updated when enabled in the config on almost every page view. A solution would be to add SQL_NO_CACHE after the selects on these queries. This however would break the queries for PostgreSQL. What would be the best way to submit a patch for this? Best regards, Hans