| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: lazy detoasting |
| Date: | 2018-05-17 13:12:05 |
| Message-ID: | b46df083-0e20-536b-12f9-0b270ebb48ee@2ndquadrant.com |
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| Lists: | pgsql-hackers |
On 5/12/18 17:25, Tom Lane wrote:
> Anyway, attached is a revised patch. I found a test case for
> expanded_record_set_fields(), too.
Thank you for fixing this up.
In reviewing the committed patch, I noticed that in ER_get_flat_size()
you have removed the PG_DETOAST_DATUM() call and let
expanded_record_set_field_internal() do the de-toasting work. I had
considered that too, but my impression is that the purpose of the
PG_DETOAST_DATUM() is to de-compress for the purpose of size
computation, whereas expanded_record_set_field_internal() only does the
inlining of externally stored values and doesn't do any explicit
decompression. Is this correct?
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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