Reduce an unnecessary O(N^3) loop in lexer.
The lexer's handling of operators contained an O(N^3) hazard when
dealing with long strings of + or - characters; it seems hard to
prevent this case from being O(N^2), but the additional N multiplier
was not needed.
Backpatch all the way since this has been there since 7.x, and it
presents at least a mild hazard in that trying to do Bind, PREPARE or
EXPLAIN on a hostile query could take excessive time (without
honouring cancels or timeouts) even if the query was never executed.
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/d4a63f829702cf28adb5db7e2ed44d2d9d893451
Modified Files
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src/backend/parser/scan.l | 27 ++++++++++++++++++++-------
src/fe_utils/psqlscan.l | 27 ++++++++++++++++++++-------
src/interfaces/ecpg/preproc/pgc.l | 29 +++++++++++++++++++++--------
3 files changed, 61 insertions(+), 22 deletions(-)