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Re: get_rel_* functions in lsyscache.c - Mailing list pgsql-hackers

From Tom Lane
Subject Re: get_rel_* functions in lsyscache.c
Date
Msg-id [email protected]
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In response to get_rel_* functions in lsyscache.c  (Jaime Casanova <[email protected]>)
List pgsql-hackers
Jaime Casanova <[email protected]> writes:
> Hi, i have a doubt...
> it seems to me that the get_rel_* functions in lsyscache do the same as doing 
> heap_open(); 
> Calling the appropiate macro Relation*
> heap_close();

> is there any difference between them? in wich situation is one better
> than the other?

The lsyscache functions are just notational convenience --- they're
shorter to write and easier to read than accessing the underlying
catalog entries for yourself.  However, I'd usually only use them
to pull one or two items from a given catalog entries; if I need
several fields from the same catalog entry, I'd open the catalog
entry just once and grab the fields directly, to avoid multiple
cache searches.
        regards, tom lane


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