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(parent: fdc60bd) | patch
Teach planner about the idea that a mergejoin won't necessarily read
authorTom Lane <tgl@sss.pgh.pa.us>
Fri, 1 Mar 2002 04:09:28 +0000 (04:09 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Fri, 1 Mar 2002 04:09:28 +0000 (04:09 +0000)
commitf8c109528cc6e7a6230b86e75374e0210db2ba56
tree2bafa469cab841f2c7a24bc8fae1bfd70388ec61tree | snapshot
parentfdc60bd9d912af7e507705d87ed70f6f8c5fbd5bcommit | diff
Teach planner about the idea that a mergejoin won't necessarily read
both input streams to the end.  If one variable's range is much less
than the other, an indexscan-based merge can win by not scanning all
of the other table.  Per example from Reinhard Max.
src/backend/executor/nodeMergejoin.c diff | blob | history
src/backend/optimizer/path/costsize.c diff | blob | history
src/backend/utils/adt/selfuncs.c diff | blob | history
src/backend/utils/cache/lsyscache.c diff | blob | history
src/include/utils/lsyscache.h diff | blob | history
src/include/utils/selfuncs.h diff | blob | history
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