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
Branch
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master
Details
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http://git.postgresql.org/pg/commitdiff/2146f13408cdb85c738364fe8f7965209e08c6be
Modified Files
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contrib/postgres_fdw/deparse.c | 3 -
src/backend/nodes/nodeFuncs.c | 8 +++
src/backend/nodes/outfuncs.c | 9 ---
src/backend/optimizer/prep/prepjointree.c | 6 +-
src/backend/optimizer/prep/prepqual.c | 13 ++--
src/backend/optimizer/util/clauses.c | 15 ++--
src/backend/parser/gram.y | 110 ++++++++++++++++++++---------
src/backend/parser/parse_clause.c | 21 +++---
src/backend/parser/parse_expr.c | 98 +++++++++++--------------
src/include/nodes/parsenodes.h | 3 -
src/include/nodes/primnodes.h | 8 +--
src/test/regress/expected/rules.out | 2 +-
12 files changed, 155 insertions(+), 141 deletions(-)