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782c16c6a1
for example, an SQL function can be used in a functional index. (I make no promises about speed, but it'll work ;-).) Clean up and simplify handling of functions returning sets.
68 lines
2.2 KiB
C
68 lines
2.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* fcache.h
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* Declarations for function cache records.
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*
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* The first time any Oper or Func node is evaluated, we compute a cache
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* record for the function being invoked, and save a pointer to the cache
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* record in the Oper or Func node. This saves repeated lookup of info
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* about the function.
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: fcache.h,v 1.14 2000/08/24 03:29:14 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef FCACHE_H
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#define FCACHE_H
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#include "fmgr.h"
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#include "nodes/execnodes.h"
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/*
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* A FunctionCache record is built for all functions regardless of language.
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*
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* We store the fmgr lookup info to avoid recomputing it on each call.
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* We also store a prebuilt FunctionCallInfo struct. When evaluating a
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* function-returning-set, fcinfo holds the argument values across calls
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* so that we need not re-evaluate the arguments for each call. Even for
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* non-set functions, fcinfo saves a few cycles per call by allowing us to
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* avoid redundant setup of its fields.
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*/
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typedef struct FunctionCache
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{
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/*
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* Function manager's lookup info for the target function.
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*/
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FmgrInfo func;
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/*
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* Per-call info for calling the target function. Unvarying fields
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* are set up by init_fcache(). Argument values are filled in as needed.
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*/
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FunctionCallInfoData fcinfo;
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/*
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* "Resultinfo" node --- used only if target function returns a set.
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*/
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ReturnSetInfo rsinfo;
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/*
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* argsValid is true when we are evaluating a set-valued function and
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* we are in the middle of a call series; we want to pass the same
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* argument values to the function again (and again, until it returns
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* ExprEndResult).
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*/
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bool argsValid; /* TRUE if fcinfo contains valid arguments */
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/*
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* hasSetArg is true if we found a set-valued argument to the function.
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* This causes the function result to be a set as well.
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*/
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bool hasSetArg; /* some argument returns a set */
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} FunctionCache;
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extern FunctionCachePtr init_fcache(Oid foid, int nargs,
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MemoryContext fcacheCxt);
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#endif /* FCACHE_H */
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