look at the size of my wordpress database tables:
are there simple ways to optimize it? I fear of running out of memory one day
maybe bad collation? how can I analyze what is eating up so much space in the posts and post meta tables?
One thing you can do to help reduce the amount of bloat is add a plugin that controls the number of previous revisions kept for Pages, Posts, etc (preferably one that allows for separate values for each type, such as last 5 revisions for pages and last 20 revisions for posts, or whatever.)
There are numerous plugins that handle this, check around https://wordpress.org/plugins/search/revision+control/ and similar
The thing i do for this to minimize and optimize the database is by adding a two line of code on config.php
define('AUTOSAVE_INTERVAL', 300 ); //seconds (default is 60) define('WP_POST_REVISIONS', 5 ); //alter number of post revisions kept.
you can also use wp-optimize plugin to optimize your Database and cleaning your WordPress database so that it runs at maximum efficiency.