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Overview
Comment:Update comments in the ANALYZE command that describe how the Stat4Accum objecct is passed around within the VDBE. No changes to functional code.
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SHA1: 9779c7a9eb1e2bd36e9286331a9314f064014d80
User & Date: drh 2014-09-01 23:06:44.401
Context
2014-09-05
05:58
Fix harmless compiler warning. (check-in: 7331190677 user: mistachkin tags: trunk)
2014-09-02
19:59
Add an experimental extension for applying bulk updates to databases. (check-in: 2954ab5010 user: dan tags: ota-update)
15:57
Merge the latest trunk changes into the apple-osx branch. (check-in: 696dc935f7 user: drh tags: apple-osx)
15:49
Merge the latest trunk changes, including the multi-threaded sorter, into the sessions branch. (check-in: d4cce2c71e user: drh tags: sessions)
2014-09-01
23:06
Update comments in the ANALYZE command that describe how the Stat4Accum objecct is passed around within the VDBE. No changes to functional code. (check-in: 9779c7a9eb user: drh tags: trunk)
22:34
Avoid a confusing (though correct) argument to the sqlite3_result_blob() function in the implementation of ANALYZE. (check-in: 4cae93f8ae user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/analyze.c.
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**
** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
** PRIMARY KEY of the table.  The covering index that implements the
** original WITHOUT ROWID table as N==K as a special case.
**
** This routine allocates the Stat4Accum object in heap memory. The return 
** value is a pointer to the the Stat4Accum object encoded as a blob (i.e. 

** the size of the blob is sizeof(void*) bytes). 
*/
static void statInit(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Stat4Accum *p;







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**
** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
** PRIMARY KEY of the table.  The covering index that implements the
** original WITHOUT ROWID table as N==K as a special case.
**
** This routine allocates the Stat4Accum object in heap memory. The return 
** value is a pointer to the the Stat4Accum object.  The datatype of the
** return value is BLOB, but it is really just a pointer to the Stat4Accum
** object.
*/
static void statInit(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Stat4Accum *p;
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    for(i=0; i<nCol; i++){
      p->aBest[i].iCol = i;
    }
  }
#endif

  /* Return a pointer to the allocated object to the caller */



  sqlite3_result_blob(context, p, sizeof(*p), stat4Destructor);
}
static const FuncDef statInitFuncdef = {
  2+IsStat34,      /* nArg */
  SQLITE_UTF8,     /* funcFlags */
  0,               /* pUserData */
  0,               /* pNext */







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    for(i=0; i<nCol; i++){
      p->aBest[i].iCol = i;
    }
  }
#endif

  /* Return a pointer to the allocated object to the caller.  Note that
  ** only the pointer (the 2nd parameter) matters.  The size of the object
  ** (given by the 3rd parameter) is never used and can be any positive
  ** value. */
  sqlite3_result_blob(context, p, sizeof(*p), stat4Destructor);
}
static const FuncDef statInitFuncdef = {
  2+IsStat34,      /* nArg */
  SQLITE_UTF8,     /* funcFlags */
  0,               /* pUserData */
  0,               /* pNext */
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#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */

/*
** Implementation of the stat_get(P,J) SQL function.  This routine is
** used to query statistical information that has been gathered into
** the Stat4Accum object by prior calls to stat_push().  The P parameter
** is a BLOB which is decoded into a pointer to the Stat4Accum objects.
** The content to returned is determined by the parameter J
** which is one of the STAT_GET_xxxx values defined above.
**
** If neither STAT3 nor STAT4 are enabled, then J is always
** STAT_GET_STAT1 and is hence omitted and this routine becomes
** a one-parameter function, stat_get(P), that always returns the
** stat1 table entry information.







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#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */

/*
** Implementation of the stat_get(P,J) SQL function.  This routine is
** used to query statistical information that has been gathered into
** the Stat4Accum object by prior calls to stat_push().  The P parameter
** has type BLOB but it is really just a pointer to the Stat4Accum object.
** The content to returned is determined by the parameter J
** which is one of the STAT_GET_xxxx values defined above.
**
** If neither STAT3 nor STAT4 are enabled, then J is always
** STAT_GET_STAT1 and is hence omitted and this routine becomes
** a one-parameter function, stat_get(P), that always returns the
** stat1 table entry information.