Обсуждение: pgsql/src/backend/optimizer/prep prepunion.c

CVSROOT:    /cvsroot
Module name:    pgsql
Changes by:    tgl@postgresql.org    01/11/12 15:04:20

Modified files:
    src/backend/optimizer/prep: prepunion.c

Log message:
    If the inputs of a UNION/INTERSECT/EXCEPT construct all agree on the
    typmod of a particular column, mark the output with that same typmod,
    not -1 as formerly.  -1 is still used if there is any disagreement.
    Part of response to bug#513.

> CVSROOT:    /cvsroot
> Module name:    pgsql
> Changes by:    tgl@postgresql.org    01/11/12 15:04:20
>
> Modified files:
>     src/backend/optimizer/prep: prepunion.c
>
> Log message:
>     If the inputs of a UNION/INTERSECT/EXCEPT construct all agree on the
>     typmod of a particular column, mark the output with that same typmod,
>     not -1 as formerly.  -1 is still used if there is any disagreement.
>     Part of response to bug#513.

Very nice.  I know we punted typmod on several places because where
we had conflicting typmod cases in expressions.  This seems like a nice
idea, keep the typmods if they are all the same.  Any more places I can
add to TODO?

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
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Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Very nice.  I know we punted typmod on several places because where
> we had conflicting typmod cases in expressions.  This seems like a nice
> idea, keep the typmods if they are all the same.  Any more places I can
> add to TODO?

UNION and CASE are the only examples where we do type resolution that
way, so they are probably the only ones that have any reason to do
typmod resolution this way ...

            regards, tom lane