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904b171a46
We already tried to fix this in commits3f7323cbbet al (and follow-on fixes), but now it emerges that there are still unfixed cases; moreover, these cases affect all branches not only pre-v14. I thought we had eliminated all cases of making multiple clones of an UPDATE's target list when we nuked inheritance_planner. But it turns out we still do that in some partitioned-UPDATE cases, notably including INSERT ... ON CONFLICT UPDATE, because ExecInitPartitionInfo thinks it's okay to clone and modify the parent's targetlist. This fix is based on a suggestion from Andres Freund: let's stop abusing the ParamExecData.execPlan mechanism, which was only ever meant to handle initplans, and instead solve the execution timing problem by having the expression compiler move MULTIEXPR_SUBLINK steps to the front of their expression step lists. This is feasible because (a) all branches still in support compile the entire targetlist of an UPDATE into a single ExprState, and (b) we know that all MULTIEXPR_SUBLINKs do need to be evaluated --- none could be buried inside a CASE, for example. There is a minor semantics change concerning the order of execution of the MULTIEXPR's subquery versus other parts of the parent targetlist, but that seems like something we can get away with. By doing that, we no longer need to worry about whether different clones of a MULTIEXPR_SUBLINK share output Params; their usage of that data structure won't overlap. Per bug #17800 from Alexander Lakhin. Back-patch to all supported branches. In v13 and earlier, we can revert3f7323cbband follow-on fixes; however, I chose to keep the SubPlan.subLinkId field added inccbb54c72. We don't need that anymore in the core code, but it's cheap enough to fill, and removing a plan node field in a minor release seems like it'd be asking for trouble. Andres Freund and Tom Lane Discussion: https://postgr.es/m/17800-ff90866b3906c964@postgresql.org
40 lines
1.5 KiB
C
40 lines
1.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* subselect.h
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* Planning routines for subselects.
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*
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* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/optimizer/subselect.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SUBSELECT_H
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#define SUBSELECT_H
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#include "nodes/pathnodes.h"
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#include "nodes/plannodes.h"
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extern void SS_process_ctes(PlannerInfo *root);
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extern JoinExpr *convert_ANY_sublink_to_join(PlannerInfo *root,
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SubLink *sublink,
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Relids available_rels);
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extern JoinExpr *convert_EXISTS_sublink_to_join(PlannerInfo *root,
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SubLink *sublink,
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bool under_not,
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Relids available_rels);
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extern Node *SS_replace_correlation_vars(PlannerInfo *root, Node *expr);
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extern Node *SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual);
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extern void SS_identify_outer_params(PlannerInfo *root);
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extern void SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel);
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extern void SS_attach_initplans(PlannerInfo *root, Plan *plan);
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extern void SS_finalize_plan(PlannerInfo *root, Plan *plan);
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extern Param *SS_make_initplan_output_param(PlannerInfo *root,
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Oid resulttype, int32 resulttypmod,
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Oid resultcollation);
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extern void SS_make_initplan_from_plan(PlannerInfo *root,
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PlannerInfo *subroot, Plan *plan,
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Param *prm);
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#endif /* SUBSELECT_H */
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