Re: vacuum, performance, and MVCC - Mailing list pgsql-hackers

From Tom Lane
Subject Re: vacuum, performance, and MVCC
Date
Msg-id 7243.1151011876@sss.pgh.pa.us
Whole thread Raw
In response to Re: vacuum, performance, and MVCC  (Jim Nasby <jnasby@pervasive.com>)
Responses Row comparison for tables (was Re: vacuum, performance, and MVCC)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Jim Nasby <jnasby@pervasive.com> writes:
> What would be nice to add is the ability to perform that check more  
> easily. As of 8.1...
> ...
> if NEW=OLD then
> ...
> ERROR:  operator does not exist: test = test
> HINT:  No operator matches the given name and argument type(s). You  
> may need to add explicit type casts.

Hmm, there seems to be some asymmetry in the handling, because it works
for anonymous row constructors:

regression=# select row(a.*) = row(a.*) from int8_tbl a;
ERROR:  operator does not exist: int8_tbl = int8_tbl
LINE 1: select row(a.*) = row(a.*) from int8_tbl a;                       ^
HINT:  No operator matches the given name and argument type(s). You may need to
add explicit type casts.

regression=# select row(a.q1,a.q2) = row(a.q1,a.q2) from int8_tbl a;?column?
----------ttttt
(5 rows)


Someone oughta look into that...
        regards, tom lane


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