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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2014-06-16 15:55:05 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2014-06-16 15:55:30 -0400 |
| commit | 2146f13408cdb85c738364fe8f7965209e08c6be (patch) | |
| tree | 9c5989a33d072788a51411dd7ee1bedb14f2280d /contrib/postgres_fdw/deparse.c | |
| parent | ac608fe758455804f26179ea7c556e7752e453e8 (diff) | |
| download | postgresql-2146f13408cdb85c738364fe8f7965209e08c6be.tar.gz postgresql-2146f13408cdb85c738364fe8f7965209e08c6be.zip | |
Avoid recursion when processing simple lists of AND'ed or OR'ed clauses.
Since most of the system thinks AND and OR are N-argument expressions
anyway, let's have the grammar generate a representation of that form when
dealing with input like "x AND y AND z AND ...", rather than generating
a deeply-nested binary tree that just has to be flattened later by the
planner. This avoids stack overflow in parse analysis when dealing with
queries having more than a few thousand such clauses; and in any case it
removes some rather unsightly inconsistencies, since some parts of parse
analysis were generating N-argument ANDs/ORs already.
It's still possible to get a stack overflow with weirdly parenthesized
input, such as "x AND (y AND (z AND ( ... )))", but such cases are not
mainstream usage. The maximum depth of parenthesization is already
limited by Bison's stack in such cases, anyway, so that the limit is
probably fairly platform-independent.
Patch originally by Gurjeet Singh, heavily revised by me
Diffstat (limited to 'contrib/postgres_fdw/deparse.c')
| -rw-r--r-- | contrib/postgres_fdw/deparse.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c index d7d9b9c77d2..322138dd0cd 100644 --- a/contrib/postgres_fdw/deparse.c +++ b/contrib/postgres_fdw/deparse.c @@ -1716,9 +1716,6 @@ deparseRelabelType(RelabelType *node, deparse_expr_cxt *context) /* * Deparse a BoolExpr node. - * - * Note: by the time we get here, AND and OR expressions have been flattened - * into N-argument form, so we'd better be prepared to deal with that. */ static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context) |