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Don't Memoize lateral joins with volatile join conditions

The use of Memoize was already disabled in normal joins when the joinconditions had volatile functions per the code inmatch_opclause_to_indexcol(). Ordinarily, the parameterization for theinner side of a nested loop will be an Index Scan or at least eventuallylead to an index scan (perhaps nested several joins deep). However, forlateral joins, that's not the case and seq scans can be parameterizedtoo, so we can't rely on match_opclause_to_indexcol().Here we explicitly check the parameterization for volatile functions anddon't consider the generation of a Memoize path when such functionsare present.Author: Richard GuoDiscussion:https://postgr.es/m/CAMbWs49nHFnHbpepLsv_yF3qkpCS4BdB-v8HoJVv8_=Oat0u_w@mail.gmail.comBackpatch-through: 14, where Memoize was introduced

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src/backend/optimizer/path
- joinpath.c

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`‎src/backend/optimizer/path/joinpath.c`

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Original file line number	Diff line number	Diff line change
`@@ -667,6 +667,23 @@ get_memoize_path(PlannerInfo root, RelOptInfo innerrel,`
`667`	`667`	`returnNULL;`
`668`	`668`	`}`
`669`	`669`
	`670`	`+/*`
	`671`	`+ * Also check the parameterized path restrictinfos for volatile functions.`
	`672`	`+ * Indexed functions must be immutable so shouldn't have any volatile`
	`673`	`+ * functions, however, with a lateral join the inner scan may not be an`
	`674`	`+ * index scan.`
	`675`	`+ */`
	`676`	`+if (inner_path->param_info!=NULL)`
	`677`	`+{`
	`678`	`+foreach(lc,inner_path->param_info->ppi_clauses)`
	`679`	`+{`
	`680`	`+RestrictInforinfo= (RestrictInfo)lfirst(lc);`
	`681`	`+`
	`682`	`+if (contain_volatile_functions((Node*)rinfo))`
	`683`	`+returnNULL;`
	`684`	`+}`
	`685`	`+}`
	`686`	`+`
`670`	`687`	`/* Check if we have hash ops for each parameter to the path */`
`671`	`688`	`if (paraminfo_get_equal_hashops(root,`
`672`	`689`	`inner_path->param_info,`

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Commit990c365

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`‎src/backend/optimizer/path/joinpath.c`

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