** with the named table are deleted. If zWhere==0, then code is generated
** to delete all stat table entries.
*/
static void openStatTable(
  Parse *pParse,          /* Parsing context */
  int iDb,                /* The database we are looking in */
  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
  const char *zWhere,     /* Delete entries for this table or index */
  const char *zWhereType  /* Either "tbl" or "idx" */
){
  static const struct {
    const char *zName;
    const char *zCols;
  } aTable[] = {
    { "sqlite_stat1", "tbl,idx,stat" },
#ifdef SQLITE_ENABLE_STAT2

      /* The table already exists. If zWhere is not NULL, delete all entries 
      ** associated with the table zWhere. If zWhere is NULL, delete the
      ** entire contents of the table. */
      aRoot[i] = pStat->tnum;
      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
      if( zWhere ){
        sqlite3NestedParse(pParse,
           "DELETE FROM %Q.%s WHERE %s=%Q", pDb->zName, zTab, zWhereType, zWhere
        );
      }else{
        /* The sqlite_stat[12] table already exists.  Delete all rows. */
        sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb);
      }
    }
  }

/*
** Generate code to do an analysis of all indices associated with
** a single table.
*/
static void analyzeOneTable(
  Parse *pParse,   /* Parser context */
  Table *pTab,     /* Table whose indices are to be analyzed */
  Index *pOnlyIdx, /* If not NULL, only analyze this one index */
  int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
  int iMem         /* Available memory locations begin here */
){
  sqlite3 *db = pParse->db;    /* Database handle */
  Index *pIdx;                 /* An index to being analyzed */
  int iIdxCur;                 /* Cursor open on index being analyzed */
  Vdbe *v;                     /* The virtual machine being built up */

  /* Establish a read-lock on the table at the shared-cache level. */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

  iIdxCur = pParse->nTab++;
  sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0);
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    int nCol;
    KeyInfo *pKey;

    if( pOnlyIdx && pOnlyIdx!=pIdx ) continue;
    nCol = pIdx->nColumn;
    pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    if( iMem+1+(nCol*2)>pParse->nMem ){
      pParse->nMem = iMem+1+(nCol*2);
    }

    /* Open a cursor to the index to be analyzed. */
    assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) );
    sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb,

  HashElem *k;
  int iStatCur;
  int iMem;

  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab;
  pParse->nTab += 2;
  openStatTable(pParse, iDb, iStatCur, 0, 0);
  iMem = pParse->nMem+1;
  for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
    Table *pTab = (Table*)sqliteHashData(k);
    analyzeOneTable(pParse, pTab, 0, iStatCur, iMem);
  }
  loadAnalysis(pParse, iDb);
}

/*
** Generate code that will do an analysis of a single table in
** a database.  If pOnlyIdx is not NULL then it is a single index
** in pTab that should be analyzed.
*/
static void analyzeTable(Parse *pParse, Table *pTab, Index *pOnlyIdx){
  int iDb;
  int iStatCur;

  assert( pTab!=0 );
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab;
  pParse->nTab += 2;
  if( pOnlyIdx ){
    openStatTable(pParse, iDb, iStatCur, pOnlyIdx->zName, "idx");
  }else{
    openStatTable(pParse, iDb, iStatCur, pTab->zName, "tbl");
  }
  analyzeOneTable(pParse, pTab, pOnlyIdx, iStatCur, pParse->nMem+1);
  loadAnalysis(pParse, iDb);
}

/*
** Generate code for the ANALYZE command.  The parser calls this routine
** when it recognizes an ANALYZE command.
**

*/
void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
  sqlite3 *db = pParse->db;
  int iDb;
  int i;
  char *z, *zDb;
  Table *pTab;
  Index *pIdx;
  Token *pTableName;

  /* Read the database schema. If an error occurs, leave an error message
  ** and code in pParse and return NULL. */
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    return;

    /* Form 2:  Analyze the database or table named */
    iDb = sqlite3FindDb(db, pName1);
    if( iDb>=0 ){
      analyzeDatabase(pParse, iDb);
    }else{
      z = sqlite3NameFromToken(db, pName1);
      if( z ){
        if( (pIdx = sqlite3FindIndex(db, z, 0))!=0 ){
          analyzeTable(pParse, pIdx->pTable, pIdx);
        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, 0))!=0 ){


          analyzeTable(pParse, pTab, 0);
        }
        sqlite3DbFree(db, z);
      }
    }
  }else{
    /* Form 3: Analyze the fully qualified table name */
    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
    if( iDb>=0 ){
      zDb = db->aDb[iDb].zName;
      z = sqlite3NameFromToken(db, pTableName);
      if( z ){
        if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){
          analyzeTable(pParse, pIdx->pTable, pIdx);
        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){


          analyzeTable(pParse, pTab, 0);
        }
        sqlite3DbFree(db, z);
      }
    }   
  }
}

/*
** Used to pass information from the analyzer reader through to the

# 2011 April 1
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
# This file implements tests for the ANALYZE command when an idnex
# name is given as the argument.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# There is nothing to test if ANALYZE is disable for this build.
#
ifcapable {!analyze} {
  finish_test
  return
}

# Generate some test data
#
do_test analyze7-1.0 {
  execsql {
    CREATE TABLE sequence(x INTEGER PRIMARY KEY);
    INSERT INTO sequence VALUES(1);
    INSERT INTO sequence VALUES(2);
    INSERT INTO sequence SELECT x+2 FROM sequence;
    INSERT INTO sequence SELECT x+4 FROM sequence;
    INSERT INTO sequence SELECT x+8 FROM sequence;
    INSERT INTO sequence SELECT x+16 FROM sequence;
    INSERT INTO sequence SELECT x+32 FROM sequence;
    INSERT INTO sequence SELECT x+64 FROM sequence;
    INSERT INTO sequence SELECT x+128 FROM sequence;
    INSERT INTO sequence SELECT x+256 FROM sequence;
    CREATE TABLE t1(a,b,c,d);
    CREATE INDEX t1a ON t1(a);
    CREATE INDEX t1b ON t1(b);
    CREATE INDEX t1cd ON t1(c,d);
    INSERT INTO t1 SELECT x, x, x/100, x FROM sequence;
    EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123;
  }
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~10 rows)}}
do_test analyze7-1.1 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b=123;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?) (~10 rows)}}
do_test analyze7-1.2 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE c=2;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1cd (c=?) (~10 rows)}}

# Run an analyze on one of the three indices.  Verify that this
# effects the row-count estimate on the one query that uses that
# one index.
#
do_test analyze7-2.0 {
  execsql {ANALYZE t1a;}
  db cache flush
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}
do_test analyze7-2.1 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b=123;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?) (~10 rows)}}
do_test analyze7-2.2 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE c=2;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1cd (c=?) (~10 rows)}}

# Verify that since the query planner now things that t1a is more
# selective than t1b, it prefers to use t1a.
#
do_test analyze7-2.3 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123 AND b=123}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}

# Run an analysis on another of the three indices.  Verify  that this
# new analysis works and does not disrupt the previous analysis.
#
do_test analyze7-3.0 {
  execsql {ANALYZE t1cd;}
  db cache flush;
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}
do_test analyze7-3.1 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b=123;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?) (~10 rows)}}
do_test analyze7-3.2 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE c=2;}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1cd (c=?) (~102 rows)}}
do_test analyze7-3.3 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123 AND b=123}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}
do_test analyze7-3.4 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE c=123 AND b=123}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?) (~2 rows)}}
do_test analyze7-3.5 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=123 AND c=123}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}
do_test analyze7-3.6 {
  execsql {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE c=123 AND d=123 AND b=123}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1cd (c=? AND d=?) (~1 rows)}}

finish_test