[Info-ingres] Comparing QEPs

[s.anderson.au at gmail.com]

Hi there

Had an issue where a query in one ABF screen started running very slowly, instead of completing instantly, it now takes twenty seconds.

Re-generating the statistics for the associated tables did not help.

As such I copied the tables to our dev box and compared the query plans Ingres created on dev vs production. On production the QEP did not utilise a secondary index, whereas on dev it did.

The dev vs production is not a perfection comparison as in the process of copying the tables across to dev, the tables were rebuilt.

I tried to force Ingres to use the secondary index by tweaking the query to explicitly join with the secondary index, but my hack did not help.

What is the best approach for this situation? Should I be rebuilding the tables involved?

Thanks
Steve