2014-01-27 Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>:
> (2014/01/25 11:27), Shigeru Hanada wrote:
> Yeah, the consistency is essential for its ease of use. But I'm not sure
> that inherited stats ignoring foreign tables is actually useful for query
> optimization. What I think about the consistency is a) the ANALYZE command
> with no table names skips ANALYZEing inheritance trees that include at least
> one foreign table as a child, but b) the ANALYZE command with a table name
> indicating an inheritance tree that includes any foreign tables does compute
> the inherited stats in the same way as an inheritance tree consiting of only
> ordinary tables by acquiring the sample rows from each foreign table on the
> far side.
b) sounds little complex to understand or explain.
Is it too big change that making ANALYZE command to handle foreign
tables too even if no table name was specified? IIRC, performance
issue was the reason to exclude foreign tables from auto-analyze
processing. ANALYZEing large database contains local huge data also
takes long time. One idea to avoid unexpected long processing is to
add option to foreign tables to mark it as "not-auto-analyzable".
Thoughts?
--
Shigeru HANADA