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The EvalPlanQual machinery assumes that any initplans (that is, uncorrelated sub-selects) used during an EPQ recheck would have already been evaluated during the main query; this is implicit in the fact that execPlan pointers are not copied into the EPQ estate's es_param_exec_vals. But it's possible for that assumption to fail, if the initplan is only reached conditionally. For example, a sub-select inside a CASE expression could be reached during a recheck when it had not been previously, if the CASE test depends on a column that was just updated. This bug is old, appearing to date back to my rewrite of EvalPlanQual in commit9f2ee8f28, but was not detected until Kyle Samson reported a case. To fix, force all not-yet-evaluated initplans used within the EPQ plan subtree to be evaluated at the start of the recheck, before entering the EPQ environment. This could be inefficient, if such an initplan is expensive and goes unused again during the recheck --- but that's piling one layer of improbability atop another. It doesn't seem worth adding more complexity to prevent that, at least not in the back branches. It was convenient to use the new-in-v11 ExecEvalParamExecParams function to implement this, but I didn't like either its name or the specifics of its API, so revise that. Back-patch all the way. Rather than rewrite the patch to avoid depending on bms_next_member() in the oldest branches, I chose to back-patch that function into 9.4 and 9.3. (This isn't the first time back-patches have needed that, and it exhausted my patience.) I also chose to back-patch some test cases added by commits71404af2aand342a1ffa2into 9.4 and 9.3, so that the 9.x versions of eval-plan-qual.spec are all the same. Andrew Gierth diagnosed the problem and contributed the added test cases, though the actual code changes are by me. Discussion: https://postgr.es/m/A033A40A-B234-4324-BE37-272279F7B627@tripadvisor.com
97 lines
3.4 KiB
C
97 lines
3.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* bitmapset.h
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* PostgreSQL generic bitmap set package
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*
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* A bitmap set can represent any set of nonnegative integers, although
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* it is mainly intended for sets where the maximum value is not large,
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* say at most a few hundred. By convention, a NULL pointer is always
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* accepted by all operations to represent the empty set. (But beware
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* that this is not the only representation of the empty set. Use
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* bms_is_empty() in preference to testing for NULL.)
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*
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*
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* Copyright (c) 2003-2013, PostgreSQL Global Development Group
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*
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* src/include/nodes/bitmapset.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef BITMAPSET_H
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#define BITMAPSET_H
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/*
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* Data representation
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*/
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/* The unit size can be adjusted by changing these three declarations: */
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#define BITS_PER_BITMAPWORD 32
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typedef uint32 bitmapword; /* must be an unsigned type */
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typedef int32 signedbitmapword; /* must be the matching signed type */
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typedef struct Bitmapset
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{
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int nwords; /* number of words in array */
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bitmapword words[1]; /* really [nwords] */
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} Bitmapset; /* VARIABLE LENGTH STRUCT */
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/* result of bms_subset_compare */
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typedef enum
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{
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BMS_EQUAL, /* sets are equal */
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BMS_SUBSET1, /* first set is a subset of the second */
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BMS_SUBSET2, /* second set is a subset of the first */
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BMS_DIFFERENT /* neither set is a subset of the other */
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} BMS_Comparison;
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/* result of bms_membership */
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typedef enum
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{
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BMS_EMPTY_SET, /* 0 members */
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BMS_SINGLETON, /* 1 member */
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BMS_MULTIPLE /* >1 member */
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} BMS_Membership;
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/*
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* function prototypes in nodes/bitmapset.c
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*/
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extern Bitmapset *bms_copy(const Bitmapset *a);
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extern bool bms_equal(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_make_singleton(int x);
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extern void bms_free(Bitmapset *a);
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extern Bitmapset *bms_union(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_intersect(const Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_difference(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_is_subset(const Bitmapset *a, const Bitmapset *b);
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extern BMS_Comparison bms_subset_compare(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_is_member(int x, const Bitmapset *a);
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extern bool bms_overlap(const Bitmapset *a, const Bitmapset *b);
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extern bool bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b);
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extern int bms_singleton_member(const Bitmapset *a);
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extern int bms_num_members(const Bitmapset *a);
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/* optimized tests when we don't need to know exact membership count: */
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extern BMS_Membership bms_membership(const Bitmapset *a);
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extern bool bms_is_empty(const Bitmapset *a);
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/* these routines recycle (modify or free) their non-const inputs: */
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extern Bitmapset *bms_add_member(Bitmapset *a, int x);
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extern Bitmapset *bms_del_member(Bitmapset *a, int x);
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extern Bitmapset *bms_add_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_int_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_del_members(Bitmapset *a, const Bitmapset *b);
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extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b);
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/* support for iterating through the integer elements of a set: */
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extern int bms_first_member(Bitmapset *a);
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extern int bms_next_member(const Bitmapset *a, int prevbit);
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/* support for hashtables using Bitmapsets as keys: */
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extern uint32 bms_hash_value(const Bitmapset *a);
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#endif /* BITMAPSET_H */
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