If you feel that one of your pages takes more time than it should to be generated, chances are that you're making too many RQL queries. Obviously, there are other reasons but my personal experience tends to show this is first thing to track down. Luckily for us, CubicWeb provides a configuration option to log rql queries. In your all-in-one.conf file, set the query-log-file option:

# web application query log file
query-log-file=~/myapp-rql.log

Then restart your application, reload your page and stop your application. The file myapp-rql.log now contains the list of RQL queries that were executed during your test. It's a simple text file containing lines such as:

Any A WHERE X eid %(x)s, X lastname A {'x': 448} -- (0.002 sec, 0.010 CPU sec)
Any A WHERE X eid %(x)s, X firstname A {'x': 447} -- (0.002 sec, 0.000 CPU sec)

The structure of each line is:

<RQL QUERY> <QUERY ARGS IF ANY> -- <TIME SPENT>

Use the cubicweb-ctl exlog command to examine and summarize data found in such a file:

adim@crater:~$ cubicweb-ctl exlog < ~/myapp-rql.log
0.07 50 Any A WHERE X eid %(x)s, X firstname A {}
0.05 50 Any A WHERE X eid %(x)s, X lastname A {}
0.01 1 Any X,AA ORDERBY AA DESC WHERE E eid %(x)s, E employees X, X modification_date AA {}
0.01 1 Any X WHERE X eid %(x)s, X owned_by U, U eid %(u)s {, }
0.01 1 Any B,T,P ORDERBY lower(T) WHERE B is Bookmark,B title T, B path P, B bookmarked_by U, U eid %(x)s {}
0.01 1 Any A,B,C,D WHERE A eid %(x)s,A name B,A creation_date C,A modification_date D {}

This command sorts and uniquifies queries so that it's easy to see where is the hot spot that needs optimization.

Having said all this, it would probably be worth talking about the fetch_attrs attribute you can define in your entity classes because it can greatly reduce the number of queries executed but I'll make a specific blog entry for this.

I should finally mention the existence of the profile option in the all-in-on.conf. If set, this option will make your application run in an hotshot session and store the results in the specified file.

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