Re: understanding explain data

Alban Hertroys wrote:
> Sim Zacks wrote:
>> Something such as: with this explain data, adding an index on table
>> tbl column A would drastically improve the efficiency. Or at least an
>> application that would say, the least efficient part of your query is
>> on this part of the code so that you could more easily figure out what
>> to do about it.
>
> The latter part is the most useful IMO, optimizing usually needs a
> (human) brain to put things into the right perspective. Adding an index
> can speed up your queries only so much, a more optimal data presentation
>  (like moving calculations to insert/update instead of select) can do a
> lot more sometimes.
>
> It looks like something like that shouldn't be too hard to write...
> Maybe it even does exist already. Personally I'd prefer a command line
> tool ;)
> It would help if you can pipe the output of explain analyze to an
> external tool from within psql.

I've got a short perl script that I throw explain output into. It's not
brilliant - can give false positives, but it will usually give you two
or three lines to look at.

For those that are interested, I've attached it.

--
   Richard Huxton
   Archonet Ltd