Re: Adding a suffix array index - Mailing list pgsql-hackers

From Troels Arvin
Subject Re: Adding a suffix array index
Date
Msg-id pan.2004.11.28.21.58.35.778498@arvin.dk
Whole thread Raw
In response to Adding a suffix array index  (Troels Arvin <troels@arvin.dk>)
Responses Re: Adding a suffix array index  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Sun, 28 Nov 2004 16:52:47 -0500, Tom Lane wrote:

> CTID (block # + line #) is the only valid pointer from an index to a
> table.

Thanks.

> I think
> though that you'd be making a serious mistake by not duplicating the
> suffixes into the index (rather than expecting to retrieve them from the
> table every time, as you seem to be contemplating).

Yes, I've thought about this, and I may end up doing that.

> You need to be able
> to scan the index and identify rows matching a query without making lots
> of probes into the table.

But is it cheaper, IO-wise to "jump" around in an index than to go back
and forth between index and tuple blocks?

-- 
Greetings from Troels Arvin, Copenhagen, Denmark




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