From: sathiya psql <sathiya.psql@gmail.com>
To: Craig Ringer <craig@postnewspapers.com.au>
Cc: pgsql-performance@postgresql.org
Subject: Re: Having MANY MANY empty columns in database
Date: Sat, 22 Mar 2008 14:38:25 +0530
Message-ID: <f966c2ee0803220208p3b47585bg788139a4a7e85bd7@mail.gmail.com> (raw)
In-Reply-To: <47E4C231.20302@postnewspapers.com.au>
References: <f966c2ee0803212110n2d84585eqf5d9bf67cdba0898@mail.gmail.com>
<47E4C231.20302@postnewspapers.com.au>
>
> OK, so your tables all have the same fields (columns), as if you used
> CREATE TABLE new_table ( LIKE some_template_table ) ?
It will contain some other unique columns for each table.
> meaning that they contain NULL values in that field for every record?
what is the value it may contain i don't know ?? we are not filling any
value !!
>
> > If you drop those columns we will gain any performance or not.....
>
I need to test... HOW to test the overall performance of database..
> However, I recall hearing that PostgreSQL keeps a null bitmap and doesn't
> use any storage for null fields. If that is correct then you probably won't
> be paying much of a price in disk I/O, but there might still be other costs.
>
if it is sure that it will not make disk I/O then it is ok
>
> I can't help wondering why you have all those useless columns in the
> first place, and why you have so many identically structured tables.
>
these are not useless columns... it should be used to update the owner of
the record, updated time, created and other stuffs, but nobody is using now.
>
> --
> Craig Ringer
>
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: sathiya.psql@gmail.com, craig@postnewspapers.com.au
Subject: Re: Having MANY MANY empty columns in database
In-Reply-To: <f966c2ee0803220208p3b47585bg788139a4a7e85bd7@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox