Re: interesting trigger behaviour in 8.3

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От Tom Lane
Тема Re: interesting trigger behaviour in 8.3
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Msg-id 11469.1217346721@sss.pgh.pa.us
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Ответ на interesting trigger behaviour in 8.3  ("Ivan Zolotukhin" <ivan.zolotukhin@gmail.com>)
Ответы Re: interesting trigger behaviour in 8.3  ("Ivan Zolotukhin" <ivan.zolotukhin@gmail.com>)
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"Ivan Zolotukhin" <ivan.zolotukhin@gmail.com> writes:
> In pseudo code it looks like the following. There are 2 tables, empty
> abstract_table with 3 columns (id, col1, col2) and many tables (e.g.
> inherited_table1_with_data) that inherit abstract_table.
> Constraint_exclusion is set up on id column and works perfectly. So
> we've got update like this

> UPDATE abstract_table SET col1 = 1, col2 = 2 WHERE id = 12345;

I bet it does not *really* look like that, but has a parameterized
WHERE clause.  As per the fine manual:

    Constraint exclusion only works when the query's WHERE clause
    contains constants. A parameterized query will not be optimized,
    since the planner cannot know which partitions the parameter value
    might select at run time. For the same reason, "stable" functions
    such as CURRENT_DATE must be avoided.


            regards, tom lane

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