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eaccfded98
Formerly we relied on checking after-the-fact to see if an expression contained aggregates, window functions, or sub-selects when it shouldn't. This is grotty, easily forgotten (indeed, we had forgotten to teach DefineIndex about rejecting window functions), and none too efficient since it requires extra traversals of the parse tree. To improve matters, define an enum type that classifies all SQL sub-expressions, store it in ParseState to show what kind of expression we are currently parsing, and make transformAggregateCall, transformWindowFuncCall, and transformSubLink check the expression type and throw error if the type indicates the construct is disallowed. This allows removal of a large number of ad-hoc checks scattered around the code base. The enum type is sufficiently fine-grained that we can still produce error messages of at least the same specificity as before. Bringing these error checks together revealed that we'd been none too consistent about phrasing of the error messages, so standardize the wording a bit. Also, rewrite checking of aggregate arguments so that it requires only one traversal of the arguments, rather than up to three as before. In passing, clean up some more comments left over from add_missing_from support, and annotate some tests that I think are dead code now that that's gone. (I didn't risk actually removing said dead code, though.)
45 lines
1.5 KiB
C
45 lines
1.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* var.h
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* prototypes for optimizer/util/var.c.
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*
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*
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* Portions Copyright (c) 1996-2012, 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/var.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef VAR_H
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#define VAR_H
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#include "nodes/relation.h"
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typedef enum
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{
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PVC_REJECT_AGGREGATES, /* throw error if Aggref found */
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PVC_INCLUDE_AGGREGATES, /* include Aggrefs in output list */
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PVC_RECURSE_AGGREGATES /* recurse into Aggref arguments */
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} PVCAggregateBehavior;
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typedef enum
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{
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PVC_REJECT_PLACEHOLDERS, /* throw error if PlaceHolderVar found */
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PVC_INCLUDE_PLACEHOLDERS, /* include PlaceHolderVars in output list */
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PVC_RECURSE_PLACEHOLDERS /* recurse into PlaceHolderVar arguments */
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} PVCPlaceHolderBehavior;
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extern Relids pull_varnos(Node *node);
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extern Relids pull_varnos_of_level(Node *node, int levelsup);
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extern void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos);
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extern List *pull_vars_of_level(Node *node, int levelsup);
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extern bool contain_var_clause(Node *node);
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extern bool contain_vars_of_level(Node *node, int levelsup);
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extern int locate_var_of_level(Node *node, int levelsup);
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extern List *pull_var_clause(Node *node, PVCAggregateBehavior aggbehavior,
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PVCPlaceHolderBehavior phbehavior);
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extern Node *flatten_join_alias_vars(PlannerInfo *root, Node *node);
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#endif /* VAR_H */
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