openerp-expert-framework team mailing list archive

[Lorenzo Battistini <lorenzo.battistini@xxxxxxxxxxx>]

On 04/16/2014 03:23 PM, Alexandre Fayolle wrote:
> Hello,
>
> I came across this while analyzing pg logs with pgbadger : postgreSQL
> does not automatically create indexes for foreign key columns, and I was
> surprised when I noticed that the ORM in OpenERP does not do this by
> default. Has anyone been doing some analysis on this and concluded that
> manual creation of such indexes was the correct thing to do because the
> read-time gains were nullified by the write-time costs ?

Sometimes I had to manually create indexes for foreign keys, especially 
when pg logs reported very slow queries.
This increased the performances.


> My gut feeling is that in most cases we want such index to be created,
> and that select should default to True for m2o fields (and then we could
> always explicitely disable index creation for the few fields for which
> this would cause harm).

In general, the queries based on foreign keys (like JOIN) are very 
selective, so it is advised to have indexes on them.

So, +1


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Lorenzo Battistini
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