git.postgresql.org Git - postgresql.git/commit
2003年1月24日 03:58:44 +0000 (03:58 +0000)
2003年1月24日 03:58:44 +0000 (03:58 +0000)
commit f5e83662d06a40f90ceb3516fc88674eb6c1e4f9
Modify planner's implied-equality-deduction code so that when a set
of known-equal expressions includes any constant expressions (including
Params from outer queries), we actively suppress any 'var = var'
clauses that are or could be deduced from the set, generating only the
deducible 'var = const' clauses instead. The idea here is to push down
the restrictions implied by the equality set to base relations whenever
possible. Once we have applied the 'var = const' clauses, the 'var = var'
clauses are redundant, and should be suppressed both to save work at
execution and to avoid double-counting restrictivity.
12 files changed:
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