Re: Index strategy
From: Mariano Corral <corral_at_iname.com>
Date: Sat, 12 Jun 2010 11:20:08 -0700 (PDT)
Message-ID: <e0da5c68-46ac-4ff5-b07f-1d9335e34ac5_at_d37g2000yqm.googlegroups.com>
On 3 jun, ,joel garry wrote:
[snip]
> I would be more paranoid than Mark about dropping unused indices,
> unless they've been tracked for a year, at least. Unless, say, you
> get overtime for tracking performance problems on New Years Eve.
Date: Sat, 12 Jun 2010 11:20:08 -0700 (PDT)
Message-ID: <e0da5c68-46ac-4ff5-b07f-1d9335e34ac5_at_d37g2000yqm.googlegroups.com>
On 3 jun, ,joel garry wrote:
[snip]
> I would be more paranoid than Mark about dropping unused indices,
> unless they've been tracked for a year, at least. Unless, say, you
> get overtime for tracking performance problems on New Years Eve.
There is always a risk when dropping an index, so you may consider to balance advantages and risks. A unnecessary index impacts negatively the performance of inserts and updates of the indexed columns. Then, the benefits of dropping an index are higher for tables with many inserts or many updates of its indexed columns. On the other hand, read-only tables can afford many indices without a performance penalty. In other words, you may assume higher risks when dropping indices for tables having many inserts or updates. For others, drop an index only when it's 100% guaranteed it'll be harmless.
Regards,
Mariano Corral
Received on Sat Jun 12 2010 - 13:20:08 CDT