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d4af2a6481
and anti joins. To do this, pass the SpecialJoinInfo struct for the current join as an additional optional argument to operator join selectivity estimation functions. This allows the estimator to tell not only what kind of join is being formed, but which variable is on which side of the join; a requirement long recognized but not dealt with till now. This also leaves the door open for future improvements in the estimators, such as accounting for the null-insertion effects of lower outer joins. I didn't do anything about that in the current patch but the information is in principle deducible from what's passed. The patch also clarifies the definition of join selectivity for semi/anti joins: it's the fraction of the left input that has (at least one) match in the right input. This allows getting rid of some very fuzzy thinking that I had committed in the original 7.4-era IN-optimization patch. There's probably room to estimate this better than the present patch does, but at least we know what to estimate. Since I had to touch CREATE OPERATOR anyway to allow a variant signature for join estimator functions, I took the opportunity to add a couple of additional checks that were missing, per my recent message to -hackers: * Check that estimator functions return float8; * Require execute permission at the time of CREATE OPERATOR on the operator's function as well as the estimator functions; * Require ownership of any pre-existing operator that's modified by the command. I also moved the lookup of the functions out of OperatorCreate() and into operatorcmds.c, since that seemed more consistent with most of the other catalog object creation processes, eg CREATE TYPE. |
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| .. | ||
| aggregatecmds.c | ||
| alter.c | ||
| analyze.c | ||
| async.c | ||
| cluster.c | ||
| comment.c | ||
| conversioncmds.c | ||
| copy.c | ||
| dbcommands.c | ||
| define.c | ||
| discard.c | ||
| explain.c | ||
| functioncmds.c | ||
| indexcmds.c | ||
| lockcmds.c | ||
| Makefile | ||
| opclasscmds.c | ||
| operatorcmds.c | ||
| portalcmds.c | ||
| prepare.c | ||
| proclang.c | ||
| schemacmds.c | ||
| sequence.c | ||
| tablecmds.c | ||
| tablespace.c | ||
| trigger.c | ||
| tsearchcmds.c | ||
| typecmds.c | ||
| user.c | ||
| vacuum.c | ||
| vacuumlazy.c | ||
| variable.c | ||
| view.c | ||