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First pass at set-returning-functions in FROM, by Joe Conway with

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some kibitzing from Tom Lane.  Not everything works yet, and there's
no documentation or regression test, but let's commit this so Joe
doesn't need to cope with tracking changes in so many files ...
This commit is contained in:
Tom Lane
2002-05-12 20:10:05 +00:00
parent 71009354c8
commit f9e4f611a1
48 changed files with 1813 additions and 329 deletions
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7
src/backend/utils/fmgr/README
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@@ -383,7 +383,7 @@ If a function is marked in pg_proc as returning a set, then it is called
with fcinfo->resultinfo pointing to a node of type ReturnSetInfo. A
function that desires to return a set should raise an error "called in
context that does not accept a set result" if resultinfo is NULL or does
not point to a ReturnSetInfo node. ReturnSetInfo contains a single field
not point to a ReturnSetInfo node. ReturnSetInfo contains a field
"isDone", which should be set to one of these values:
ExprSingleResult /* expression does not return a set */
@@ -396,6 +396,11 @@ After all elements have been returned, the next call should set
isDone to ExprEndResult and return a null result. (Note it is possible
to return an empty set by doing this on the first call.)
As of 7.3, the ReturnSetInfo node also contains a link to the ExprContext
within which the function is being evaluated. This is useful for functions
that need to close down internal state when they are not run to completion:
they can register a shutdown callback function in the ExprContext.
Notes about function handlers
-----------------------------