Re: PostgreSQL and mySQL database size question - Mailing list pgsql-general

From Tom Lane
Subject Re: PostgreSQL and mySQL database size question
Date
Msg-id 19044.988658251@sss.pgh.pa.us
Whole thread Raw
In response to RE: PostgreSQL and mySQL database size question  ("Fred Ingham" <ingham@erols.com>)
List pgsql-general
"Fred Ingham" <ingham@erols.com> writes:
> After dropping and recreating the indexes I have (in KB):

Ah, that's more like it.

> So, it appears that I am running into the pathological case.

Actually, a simpler explanation would be if you'd done a bunch of
updates and/or deletes at some point.  VACUUM currently never shrinks
indexes, so the excess index space might just represent the peak size
of your tables.  (Yes, improving that is on the to-do list.)

> In short, they are all needed for acceptable performance querying and
> retrieving values from the database.

You've got common queries that do selects with WHERE clauses referencing
each one of these columns?  Possible, certainly, but seems a bit odd...

> With respect to mySQL, I did verify that mySQL did in fact have all of the
> indexes I created and that they were saved in a single file (the *.MYI).

Hm.  Anyone know how mySQL represents indexes?  That still seems awfully
small.

            regards, tom lane

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