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When stat4 information is available, try to use it to improve the truth

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probability of WHERE clause terms that do not participate in the index.

FossilOrigin-Name: 1babd6ec5d60e2c34aa1c0285ead768a88004218468e97262411973fe3487022
This commit is contained in:
drh
2020-02-22 16:58:49 +00:00
parent e8c4f03266
commit 89efac94fd
4 changed files with 60 additions and 16 deletions
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10
src/whereInt.h
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@@ -291,6 +291,7 @@ struct WhereTerm {
#define TERM_LIKE 0x0400 /* The original LIKE operator */
#define TERM_IS 0x0800 /* Term.pExpr is an IS operator */
#define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */
#define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */
/*
** An instance of the WhereScan object is used as an iterator for locating
@@ -405,13 +406,16 @@ struct WhereLoopBuilder {
UnpackedRecord *pRec; /* Probe for stat4 (if required) */
int nRecValid; /* Number of valid fields currently in pRec */
#endif
unsigned int bldFlags; /* SQLITE_BLDF_* flags */
unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */
unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */
unsigned int iPlanLimit; /* Search limiter */
};
/* Allowed values for WhereLoopBuider.bldFlags */
#define SQLITE_BLDF_INDEXED 0x0001 /* An index is used */
#define SQLITE_BLDF_UNIQUE 0x0002 /* All keys of a UNIQUE index used */
#define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */
#define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */
#define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */
/* The WhereLoopBuilder.iPlanLimit is used to limit the number of
** index+constraint combinations the query planner will consider for a