SQLite

  return 0;
}

/*
** If the Index.aSample variable is not NULL, delete the aSample[] array
** and its contents.
*/
void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){
#ifdef SQLITE_ENABLE_STAT2
  if( pIdx->aSample ){
    int j;
    for(j=0; j<SQLITE_INDEX_SAMPLES; j++){
      IndexSample *p = &pIdx->aSample[j];
      if( p->eType==SQLITE_TEXT || p->eType==SQLITE_BLOB ){
        sqlite3DbFree(db, p->u.z);
      }
    }
    sqlite3DbFree(db, pIdx->aSample);

  }
#else
  UNUSED_PARAMETER(pIdx);
#endif
}

/*

  assert( db->aDb[iDb].pBt!=0 );
  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

  /* Clear any prior statistics */
  for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
    Index *pIdx = sqliteHashData(i);
    sqlite3DefaultRowEst(pIdx);
    sqlite3DeleteIndexSamples(db, pIdx);
    pIdx->aSample = 0;
  }

  /* Check to make sure the sqlite_stat1 table exists */
  sInfo.db = db;
  sInfo.zDatabase = db->aDb[iDb].zName;
  if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
    return SQLITE_ERROR;

}

/*
** Reclaim the memory used by an index
*/
static void freeIndex(sqlite3 *db, Index *p){
#ifndef SQLITE_OMIT_ANALYZE
  sqlite3DeleteIndexSamples(db, p);
#endif
  sqlite3DbFree(db, p->zColAff);
  sqlite3DbFree(db, p);
}



















/*
** For the index called zIdxName which is found in the database iDb,
** unlike that index from its Table then remove the index from
** the index hash table and free all memory structures associated
** with the index.
*/
void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){

** This routine is called when a commit occurs.
*/
void sqlite3CommitInternalChanges(sqlite3 *db){
  db->flags &= ~SQLITE_InternChanges;
}

/*
** Delete memory allocated for the column names of a table or view (the
** Table.aCol[] array).
*/
static void sqliteDeleteColumnNames(sqlite3 *db, Table *pTable){
  int i;
  Column *pCol;
  assert( pTable!=0 );
  if( (pCol = pTable->aCol)!=0 ){
    for(i=0; i<pTable->nCol; i++, pCol++){
      sqlite3DbFree(db, pCol->zName);
      sqlite3ExprDelete(db, pCol->pDflt);
      sqlite3DbFree(db, pCol->zDflt);
      sqlite3DbFree(db, pCol->zType);
      sqlite3DbFree(db, pCol->zColl);
    }
    sqlite3DbFree(db, pTable->aCol);
  }


}

/*
** Remove the memory data structures associated with the given
** Table.  No changes are made to disk by this routine.
**
** This routine just deletes the data structure.  It does not unlink
** the table data structure from the hash table.  But it does destroy
** memory structures of the indices and foreign keys associated with 
** the table.
*/
void sqlite3DeleteTable(sqlite3 *db, Table *pTable){
  Index *pIndex, *pNext;

  assert( !pTable || pTable->nRef>0 );

  /* Do not delete the table until the reference count reaches zero. */


  if( !pTable ) return;

  if( ((!db || db->pnBytesFreed==0) && (--pTable->nRef)>0) ) return;

  /* Delete all indices associated with this table. */

  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
    pNext = pIndex->pNext;
    assert( pIndex->pSchema==pTable->pSchema );
    if( !db || db->pnBytesFreed==0 ){
      char *zName = pIndex->zName; 
      TESTONLY ( Index *pOld = ) sqlite3HashInsert(
	  &pIndex->pSchema->idxHash, zName, sqlite3Strlen30(zName), 0
      );
      assert( pOld==pIndex || pOld==0 );
    }
    freeIndex(db, pIndex);
  }

  /* Delete any foreign keys attached to this table. */
  sqlite3FkDelete(db, pTable);

  /* Delete the Table structure itself.
  */
  sqliteDeleteColumnNames(db, pTable);
  sqlite3DbFree(db, pTable->zName);
  sqlite3DbFree(db, pTable->zColAff);
  sqlite3SelectDelete(db, pTable->pSelect);
#ifndef SQLITE_OMIT_CHECK
  sqlite3ExprDelete(db, pTable->pCheck);
#endif
  sqlite3VtabClear(db, pTable);

*/
static void sqliteViewResetAll(sqlite3 *db, int idx){
  HashElem *i;
  if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
  for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
    Table *pTab = sqliteHashData(i);
    if( pTab->pSelect ){
      sqliteDeleteColumnNames(db, pTab);
      pTab->aCol = 0;
      pTab->nCol = 0;
    }
  }
  DbClearProperty(db, idx, DB_UnresetViews);
}
#else
# define sqliteViewResetAll(A,B)
#endif /* SQLITE_OMIT_VIEW */

void sqlite3FkDelete(sqlite3 *db, Table *pTab){
  FKey *pFKey;                    /* Iterator variable */
  FKey *pNext;                    /* Copy of pFKey->pNextFrom */

  for(pFKey=pTab->pFKey; pFKey; pFKey=pNext){

    /* Remove the FK from the fkeyHash hash table. */
    if( !db || db->pnBytesFreed==0 ){
      if( pFKey->pPrevTo ){
        pFKey->pPrevTo->pNextTo = pFKey->pNextTo;
      }else{
        void *p = (void *)pFKey->pNextTo;
        const char *z = (p ? pFKey->pNextTo->zTo : pFKey->zTo);
        sqlite3HashInsert(&pTab->pSchema->fkeyHash, z, sqlite3Strlen30(z), p);
      }
      if( pFKey->pNextTo ){
        pFKey->pNextTo->pPrevTo = pFKey->pPrevTo;
      }
    }

    /* EV: R-30323-21917 Each foreign key constraint in SQLite is
    ** classified as either immediate or deferred.
    */
    assert( pFKey->isDeferred==0 || pFKey->isDeferred==1 );

    /* Delete any triggers created to implement actions for this FK. */
#ifndef SQLITE_OMIT_TRIGGER
    fkTriggerDelete(db, pFKey->apTrigger[0]);
    fkTriggerDelete(db, pFKey->apTrigger[1]);
#endif






    pNext = pFKey->pNextFrom;
    sqlite3DbFree(db, pFKey);
  }
}
#endif /* ifndef SQLITE_OMIT_FOREIGN_KEY */

/*
** Free memory that might be associated with a particular database
** connection.
*/
void sqlite3DbFree(sqlite3 *db, void *p){
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( db && db->pnBytesFreed ){
    if( isLookaside(db, p) ){
      *db->pnBytesFreed += db->lookaside.sz;
    }else{
      *db->pnBytesFreed += sqlite3MallocSize(p);
    }
  }else if( isLookaside(db, p) ){
    LookasideSlot *pBuf = (LookasideSlot*)p;
    pBuf->pNext = db->lookaside.pFree;
    db->lookaside.pFree = pBuf;
    db->lookaside.nOut--;
  }else{
    assert( sqlite3MemdebugHasType(p,
                       db ? (MEMTYPE_DB|MEMTYPE_HEAP) : MEMTYPE_HEAP) );

** memory used by all pager caches associated with the database connection.
** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
** </dd>
** </dl>
*/
#define SQLITE_DBSTATUS_LOOKASIDE_USED     0
#define SQLITE_DBSTATUS_CACHE_USED         1
#define SQLITE_DBSTATUS_SCHEMA_USED        2
#define SQLITE_DBSTATUS_STMT_USED          3
#define SQLITE_DBSTATUS_MAX                3   /* Largest defined DBSTATUS */


/*
** CAPI3REF: Prepared Statement Status
**
** ^(Each prepared statement maintains various
** [SQLITE_STMTSTATUS_SORT | counters] that measure the number

  int busyTimeout;              /* Busy handler timeout, in msec */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int nSavepoint;               /* Number of non-transaction savepoints */
  int nStatement;               /* Number of nested statement-transactions  */
  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
  SubProgram *pSubProgram;      /* List of sub-programs already visited*/

#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
  /* The following variables are all protected by the STATIC_MASTER 
  ** mutex, not by sqlite3.mutex. They are used by code in notify.c. 
  **
  ** When X.pUnlockConnection==Y, that means that X is waiting for Y to
  ** unlock so that it can proceed.

CollSeq *sqlite3GetCollSeq(sqlite3*, u8, CollSeq *, const char*);
char sqlite3AffinityType(const char*);
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);
int sqlite3FindDb(sqlite3*, Token*);
int sqlite3FindDbName(sqlite3 *, const char *);
int sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DeleteIndexSamples(sqlite3*,Index*);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
void sqlite3MinimumFileFormat(Parse*, int, int);
void sqlite3SchemaFree(void *);
Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);

**
*************************************************************************
**
** This module implements the sqlite3_status() interface and related
** functionality.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** Variables in which to record status information.
*/
typedef struct sqlite3StatType sqlite3StatType;
static SQLITE_WSD struct sqlite3StatType {
  int nowValue[9];         /* Current value */

        }
      }
      sqlite3BtreeLeaveAll(db);
      *pCurrent = totalUsed;
      *pHighwater = 0;
      break;
    }

    case SQLITE_DBSTATUS_SCHEMA_USED: {
      int i;                      /* Used to iterate through schemas */
      int nByte = 0;              /* Used to accumulate return value */

      assert( db->pSubProgram==0 );
      db->pnBytesFreed = &nByte;
      for(i=0; i<db->nDb; i++){
	Schema *pSchema = db->aDb[i].pSchema;
	if( pSchema ){
  	  HashElem *p;

	  nByte += sizeof(HashElem) * (
	      pSchema->tblHash.count 
	    + pSchema->trigHash.count
	    + pSchema->idxHash.count
	    + pSchema->fkeyHash.count
	  );
	  nByte += sqlite3MallocSize(pSchema->tblHash.ht);
	  nByte += sqlite3MallocSize(pSchema->trigHash.ht);
	  nByte += sqlite3MallocSize(pSchema->idxHash.ht);
	  nByte += sqlite3MallocSize(pSchema->fkeyHash.ht);

          for(p=sqliteHashFirst(&pSchema->trigHash); p; p=sqliteHashNext(p)){
            sqlite3DeleteTrigger(db, (Trigger*)sqliteHashData(p));
          }
          for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
            sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
          }
	}
      }
      db->pnBytesFreed = 0;

      *pHighwater = 0;
      *pCurrent = nByte;
      break;
    }

    case SQLITE_DBSTATUS_STMT_USED: {
      struct Vdbe *pVdbe;         /* Used to iterate through VMs */
      int nByte = 0;              /* Used to accumulate return value */

      db->pnBytesFreed = &nByte;
      for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
        SubProgram *pSub, *pNext;
	sqlite3VdbeDeleteObject(db, pVdbe);
        for(pSub=db->pSubProgram; pSub; pSub=pNext){
	  pNext = pSub->pNext;
	  pSub->pNext = 0;
        }
	db->pSubProgram = 0;
      }
      db->pnBytesFreed = 0;

      *pHighwater = 0;
      *pCurrent = nByte;

      break;
    }

    default: {
      rc = SQLITE_ERROR;
    }
  }
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

  int getDbPointer(Tcl_Interp*, const char*, sqlite3**);
  static const struct {
    const char *zName;
    int op;
  } aOp[] = {
    { "SQLITE_DBSTATUS_LOOKASIDE_USED",    SQLITE_DBSTATUS_LOOKASIDE_USED   },
    { "SQLITE_DBSTATUS_CACHE_USED",        SQLITE_DBSTATUS_CACHE_USED       },
    { "SQLITE_DBSTATUS_SCHEMA_USED",       SQLITE_DBSTATUS_SCHEMA_USED      },
    { "SQLITE_DBSTATUS_STMT_USED",         SQLITE_DBSTATUS_STMT_USED        }
  };
  Tcl_Obj *pResult;
  if( objc!=4 ){
    Tcl_WrongNumArgs(interp, 1, objv, "PARAMETER RESETFLAG");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  int nRef;                     /* Number of pointers to this structure */
  void *token;                  /* id that may be used to recursive triggers */
  SubProgram *pNext;            /* Next sub-program already visited */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.
*/
struct VdbeOpList {

void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeDeleteObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int,int);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
  void sqlite3VdbeTrace(Vdbe*,FILE*);

*/
static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
  if( ALWAYS(pDef) && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){
    sqlite3DbFree(db, pDef);
  }
}

static void vdbeFreeOpArray(sqlite3 *, Op *, int);

/*
** Delete a P4 value if necessary.
*/
static void freeP4(sqlite3 *db, int p4type, void *p4){
  if( p4 ){
    assert( db );
    switch( p4type ){
      case P4_REAL:
      case P4_INT64:
      case P4_MPRINTF:
      case P4_DYNAMIC:
      case P4_KEYINFO:
      case P4_INTARRAY:
      case P4_KEYINFO_HANDOFF: {
        sqlite3DbFree(db, p4);
        break;
      }
      case P4_VDBEFUNC: {
        VdbeFunc *pVdbeFunc = (VdbeFunc *)p4;
        freeEphemeralFunction(db, pVdbeFunc->pFunc);
        if( db->pnBytesFreed==0 ) sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
        sqlite3DbFree(db, pVdbeFunc);
        break;
      }
      case P4_FUNCDEF: {
        freeEphemeralFunction(db, (FuncDef*)p4);
        break;
      }
      case P4_MEM: {
        sqlite3ValueFree((sqlite3_value*)p4);
        break;
      }
      case P4_VTAB : {
        if( db->pnBytesFreed==0 ) sqlite3VtabUnlock((VTable *)p4);
        break;
      }
      case P4_SUBPROGRAM : {
        if( db->pnBytesFreed ){
	  SubProgram *p = (SubProgram *)p4;
	  SubProgram *pDone;
	  for(pDone=db->pSubProgram; pDone; pDone=pDone->pNext){
	    if( pDone==p ) break;
	  }
	  if( !pDone ){
	    p->pNext = db->pSubProgram;
	    db->pSubProgram = p;
            vdbeFreeOpArray(db, p->aOp, p->nOp);
            sqlite3DbFree(db, p);
	  }
	}else{
	  sqlite3VdbeProgramDelete(db, (SubProgram *)p4, 1);
	}
        break;
      }
    }
  }
}

/*

** Release an array of N Mem elements
*/
static void releaseMemArray(Mem *p, int N){
  if( p && N ){
    Mem *pEnd;
    sqlite3 *db = p->db;
    u8 malloc_failed = db->mallocFailed;
    if( db->pnBytesFreed ){
      for(pEnd=&p[N]; p<pEnd; p++){
        sqlite3DbFree(db, p->zMalloc);
      }
    }else
    for(pEnd=&p[N]; p<pEnd; p++){
      assert( (&p[1])==pEnd || p[0].db==p[1].db );

      /* This block is really an inlined version of sqlite3VdbeMemRelease()
      ** that takes advantage of the fact that the memory cell value is 
      ** being set to NULL after releasing any dynamic resources.
      **

      if( pAux->xDelete ){
        pAux->xDelete(pAux->pAux);
      }
      pAux->pAux = 0;
    }
  }
}

/*
** Free all memory associated with the Vdbe passed as the second argument.
** The difference between this function and sqlite3VdbeDelete() is that
** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
** the database connection.
*/
void sqlite3VdbeDeleteObject(sqlite3 *db, Vdbe *p){
  assert( p->db==0 || p->db==db );
  releaseMemArray(p->aVar, p->nVar);
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  vdbeFreeOpArray(db, p->aOp, p->nOp);
  sqlite3DbFree(db, p->aLabel);
  sqlite3DbFree(db, p->aColName);
  sqlite3DbFree(db, p->zSql);
  sqlite3DbFree(db, p->pFree);
  sqlite3DbFree(db, p);
}

/*
** Delete an entire VDBE.
*/
void sqlite3VdbeDelete(Vdbe *p){
  sqlite3 *db;

  if( NEVER(p==0) ) return;
  db = p->db;
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( db->pVdbe==p );
    db->pVdbe = p->pNext;
  }
  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }






  p->magic = VDBE_MAGIC_DEAD;

  p->db = 0;
  sqlite3VdbeDeleteObject(db, p);
}

/*
** Make sure the cursor p is ready to read or write the row to which it
** was last positioned.  Return an error code if an OOM fault or I/O error
** prevents us from positioning the cursor to its correct position.
**

** The reference count of the VTable structure associated with database 
** connection db is decremented immediately (which may lead to the 
** structure being xDisconnected and free). Any other VTable structures
** in the list are moved to the sqlite3.pDisconnect list of the associated 
** database connection.
*/
void sqlite3VtabClear(sqlite3 *db, Table *p){
  if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
  if( p->azModuleArg ){
    int i;
    for(i=0; i<p->nModuleArg; i++){
      sqlite3DbFree(db, p->azModuleArg[i]);
    }
    sqlite3DbFree(db, p->azModuleArg);
  }

do_test dbstatus-1.2 {
  db eval {
    INSERT INTO t1 VALUES(zeroblob(9000));
  }
  lindex [sqlite3_db_status db SQLITE_DBSTATUS_CACHE_USED 0] 1
} [expr {$BASESZ + 10*$PAGESZ}]


proc lookaside {db} {
  expr { $::lookaside_buffer_size *
    [lindex [sqlite3_db_status $db SQLITE_DBSTATUS_LOOKASIDE_USED 0] 1]
  }
}

#---------------------------------------------------------------------------
# Run the dbstatus-2 and dbstatus-3 tests with a couple of different
# lookaside buffer sizes.
#
foreach ::lookaside_buffer_size {0 64 120} {

  #-------------------------------------------------------------------------
  # Tests for SQLITE_DBSTATUS_SCHEMA_USED.
  #
  # Each test in the following block works as follows. Each test uses a
  # different database schema.
  #
  #   1. Open a connection to an empty database. Disable statement caching.
  #
  #   2. Execute the SQL to create the database schema. Measure the total 
  #      heap and lookaside memory allocated by SQLite, and the memory 
  #      allocated for the database schema according to sqlite3_db_status().
  #
  #   3. Drop all tables in the database schema. Measure the total memory 
  #      and the schema memory again.
  #
  #   4. Repeat step 2.
  #
  #   5. Repeat step 3.
  #
  # Then test that:
  #
  #   a) The difference in schema memory quantities in steps 2 and 3 is the
  #      same as the difference in total memory in steps 2 and 3.
  #
  #   b) Step 4 reports the same amount of schema and total memory used as
  #      in step 2.
  #
  #   c) Step 5 reports the same amount of schema and total memory used as
  #      in step 3.
  #
  foreach {tn schema} { 
    1 { CREATE TABLE t1(a, b) }
    2 { CREATE TABLE t1(a PRIMARY KEY, b REFERENCES t1, c UNIQUE) }
    3 {
      CREATE TABLE t1(a, b);
      CREATE INDEX i1 ON t1(a, b);
    }
    4 {
      CREATE TABLE t1(a, b);
      CREATE TABLE t2(c, d);
      CREATE TRIGGER AFTER INSERT ON t1 BEGIN
        INSERT INTO t2 VALUES(new.a, new.b);
        SELECT * FROM t1, t2 WHERE a=c AND b=d GROUP BY b HAVING a>5 ORDER BY a;
      END;
    }
    5 {
      CREATE TABLE t1(a, b);
      CREATE TABLE t2(c, d);
      CREATE VIEW v1 AS SELECT * FROM t1 UNION SELECT * FROM t2;
    }
    6 {
      CREATE TABLE t1(a, b);
      CREATE INDEX i1 ON t1(a);
      CREATE INDEX i2 ON t1(a,b);
      CREATE INDEX i3 ON t1(b,b);
      INSERT INTO t1 VALUES(randomblob(20), randomblob(25));
      INSERT INTO t1 SELECT randomblob(20), randomblob(25) FROM t1;
      INSERT INTO t1 SELECT randomblob(20), randomblob(25) FROM t1;
      INSERT INTO t1 SELECT randomblob(20), randomblob(25) FROM t1;
      ANALYZE;
    }
    7 {
      CREATE TABLE t1(a, b);
      CREATE TABLE t2(c, d);
      CREATE VIEW v1 AS 
        SELECT * FROM t1 
        UNION 
        SELECT * FROM t2
        UNION ALL
        SELECT c||b, d||a FROM t2 LEFT OUTER JOIN t1 GROUP BY c, d
        ORDER BY 1, 2
      ;
      CREATE TRIGGER tr1 INSTEAD OF INSERT ON v1 BEGIN
        SELECT * FROM v1;
        UPDATE t1 SET a=5, b=(SELECT c FROM t2);
      END;
      SELECT * FROM v1;
    }
  } {
    set tn "$::lookaside_buffer_size-$tn"
  
    # Step 1.
    db close
    file delete -force test.db
    sqlite3 db test.db
    sqlite3_db_config_lookaside db 0 $::lookaside_buffer_size 500
    db cache size 0
  
    # Step 2.
    execsql $schema
    set nAlloc1  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc1 [lookaside db]
    set nSchema1 [lindex [sqlite3_db_status db SQLITE_DBSTATUS_SCHEMA_USED 0] 1]
  
    # Step 3.
    drop_all_tables
    set nAlloc2  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc2 [lookaside db]
    set nSchema2 [lindex [sqlite3_db_status db SQLITE_DBSTATUS_SCHEMA_USED 0] 1]
  
    # Step 4.
    execsql $schema
    set nAlloc3  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc3 [lookaside db]
    set nSchema3 [lindex [sqlite3_db_status db SQLITE_DBSTATUS_SCHEMA_USED 0] 1]
    
    # Step 5.
    drop_all_tables
    set nAlloc4  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc4 [lookaside db]
    set nSchema4 [lindex [sqlite3_db_status db SQLITE_DBSTATUS_SCHEMA_USED 0] 1]
  
    set nFree [expr {$nAlloc1-$nAlloc2}]
    do_test dbstatus-2.$tn.a { expr {$nSchema1-$nSchema2} } $nFree
    do_test dbstatus-2.$tn.b { list $nAlloc1 $nSchema1 } "$nAlloc3 $nSchema3"
    do_test dbstatus-2.$tn.c { list $nAlloc2 $nSchema2 } "$nAlloc4 $nSchema4"
  }
  
  #-------------------------------------------------------------------------
  # Tests for SQLITE_DBSTATUS_STMT_USED.
  #
  # Each test in the following block works as follows. Each test uses a
  # different database schema.
  #
  #   1. Open a connection to an empty database. Initialized the database
  #      schema.
  #
  #   2. Prepare a bunch of SQL statements. Measure the total heap and 
  #      lookaside memory allocated by SQLite, and the memory allocated 
  #      for the prepared statements according to sqlite3_db_status().
  #
  #   3. Finalize all prepared statements Measure the total memory 
  #      and the prepared statement memory again.
  #
  #   4. Repeat step 2.
  #
  #   5. Repeat step 3.
  #
  # Then test that:
  #
  #   a) The difference in schema memory quantities in steps 2 and 3 is the
  #      same as the difference in total memory in steps 2 and 3.
  #
  #   b) Step 4 reports the same amount of schema and total memory used as
  #      in step 2.
  #
  #   c) Step 5 reports the same amount of schema and total memory used as
  #      in step 3.
  #
  foreach {tn schema statements} { 
    1 { CREATE TABLE t1(a, b) } {
      SELECT * FROM t1;
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 SELECT * FROM t1;
      UPDATE t1 SET a=5;
      DELETE FROM t1;
    }
    2 {
      PRAGMA recursive_triggers = 1;
      CREATE TABLE t1(a, b);
      CREATE TRIGGER tr1 AFTER INSERT ON t1 WHEN (new.a>0) BEGIN
        INSERT INTO t1 VALUES(new.a-1, new.b);
      END;
    } {
      INSERT INTO t1 VALUES(5, 'x');
    } 
    3 {
      PRAGMA recursive_triggers = 1;
      CREATE TABLE t1(a, b);
      CREATE TABLE t2(a, b);
      CREATE TRIGGER tr1 AFTER INSERT ON t1 WHEN (new.a>0) BEGIN
        INSERT INTO t2 VALUES(new.a-1, new.b);
      END;
      CREATE TRIGGER tr2 AFTER INSERT ON t1 WHEN (new.a>0) BEGIN
        INSERT INTO t1 VALUES(new.a-1, new.b);
      END;
    } {
      INSERT INTO t1 VALUES(10, 'x');
    } 
    4 {
      CREATE TABLE t1(a, b);
    } {
      SELECT count(*) FROM t1 WHERE upper(a)='ABC';
    }
  } {
    set tn "$::lookaside_buffer_size-$tn"

    # Step 1.
    db close
    file delete -force test.db
    sqlite3 db test.db
    sqlite3_db_config_lookaside db 0 $::lookaside_buffer_size 500
    db cache size 1000
  
    execsql $schema
    db cache flush
  
    # Step 2.
    execsql $statements
    set nAlloc1  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc1 [lookaside db]
    set nStmt1   [lindex [sqlite3_db_status db SQLITE_DBSTATUS_STMT_USED 0] 1]
    execsql $statements
  
    # Step 3.
    db cache flush
    set nAlloc2  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc3 [lookaside db]
    set nStmt2   [lindex [sqlite3_db_status db SQLITE_DBSTATUS_STMT_USED 0] 1]
    
    # Step 3.
    execsql $statements
    set nAlloc3  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc3 [lookaside db]
    set nStmt3   [lindex [sqlite3_db_status db SQLITE_DBSTATUS_STMT_USED 0] 1]
    execsql $statements
  
    # Step 4.
    db cache flush
    set nAlloc4  [lindex [sqlite3_status SQLITE_STATUS_MEMORY_USED 0] 1]
    incr nAlloc4 [lookaside db]
    set nStmt4 [lindex [sqlite3_db_status db SQLITE_DBSTATUS_STMT_USED 0] 1]
  
    set nFree [expr {$nAlloc1-$nAlloc2}]
    do_test dbstatus-3.$tn.a { list $nStmt2 } {0}
    do_test dbstatus-3.$tn.b { list $nStmt1 } [list $nFree]
    do_test dbstatus-3.$tn.c { list $nAlloc1 $nStmt1 } [list $nAlloc3 $nStmt3]
    do_test dbstatus-3.$tn.d { list $nAlloc2 $nStmt2 } [list $nAlloc4 $nStmt4]
  }
}

finish_test