Re: R: R: space taken by a row & compressed data - Mailing list pgsql-general

From Greg Stark
Subject Re: R: R: space taken by a row & compressed data
Date
Msg-id 87d61dpsj4.fsf@stark.xeocode.com
Whole thread Raw
In response to Re: R: R: space taken by a row & compressed data  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: R: R: space taken by a row & compressed data
Re: R: R: space taken by a row & compressed data
List pgsql-general
Tom Lane <tgl@sss.pgh.pa.us> writes:

> "Leonardo Francalanci" <lfrancalanci@simtel.ie> writes:
> > Could you point me to some docs on this TOAST-mechanism?
> > For instance: what kind of method is used to compress data?
>
> When in doubt, read the code ;-)
> src/backend/utils/adt/pg_lzcompress.c
> src/include/utils/pg_lzcompress.h

Are toasted values stored in the table itself or in a separate table?

My understanding was that it was the latter, which leads me to wonder whether
he'll actually gain anything by having all the records in his table be
toasted. It'll mean every record lookup has to traverse two indexes, and a
sequential scan loses the sequential read performance boost.

Or am I wrong and toasted values can be stored inline?

--
greg

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