It takes SQLite explanations and visualizes them. If you have performance data in the form of I/O counts and opcode execution counts, it can also show those.
See this blog post.
you need pygraphviz... and graphviz!
It now parses the command line and has stopped being dump. Basically you just point it at a ".json" file of the right type or a ".txt" file that is the output of performing a "EXPLAIN SELECT" using the sqlite3 binary built with "--enable-debug" and it does its thing. If you are not fancy enough to build sqlite with debug, the code still has some leftover logic that is capable of parsing a schema dump, but you will need to turn that back on yourself or ask nicely.
Invoke the script with "--help" to get more details.
Commands you might run to get that nougaty information include:
sqlite3-cvs global-messages-db.sqlite 'explain SELECT * FROM messages INNER JOIN messagesText ON messages.id = messagesText.rowid WHERE id IN (SELECT docid FROM messagesText WHERE subject MATCH "sutherland") AND deleted = 0 AND folderID IS NOT NULL AND messageKey IS NOT NULL ORDER BY date DESC LIMIT 100;' > /tmp/explained.txt
$ sqlite3-cvs global-messages-db.sqlite '.schema messages%' > /tmp/schemainfo.txt