SQLite

  if( IsReuseSchema(db) && iDb!=1 ){
    Db *pDb = &db->aDb[iDb];
    SchemaPool *pSPool = pDb->pSPool;
    assert_schema_state_ok(db);
    assert( pDb->pSchema );

    if( pSPool==0 ){
      assert( pDb->pVTable==0 );
      if( bNew==0 ){
        schemaDelete(pDb->pSchema);
        pDb->pSchema = 0;
      }
    }else{
      VTable *p;
      VTable *pNext;
      for(p=pDb->pVTable; p; p=pNext){
        pNext = p->pNext;
        sqlite3VtabUnlock(p);
      }
      pDb->pVTable = 0;
      sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
      if( DbHasProperty(db, iDb, DB_SchemaLoaded) ){
        schemaRelease(pDb);
      }
      if( bNew ){
        Schema *pNew = sqlite3SchemaGet(db, 0);
        if( pNew==0 ){

}

/*
** Find and return the schema associated with a BTree.  Create
** a new one if necessary.
*/
Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
  Schema *p;
  if( pBt && (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA)==0 ){
    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
  }else{
    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
  }
  if( !p ){
    sqlite3OomFault(db);

  for(i=0; i<db->nDb; i++){
    Schema *pSchema = db->aDb[i].pSchema;
    if( pSchema ){
      for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
        Table *pTab = (Table *)sqliteHashData(p);
        if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
      }
    }
    if( i!=1 && IsReuseSchema(db) ){
      VTable *pVTable;
      VTable *pNext;
      for(pVTable=db->aDb[i].pVTable; pVTable; pVTable=pNext){
        pNext = pVTable->pNext;
        sqlite3VtabUnlock(pVTable);
      }
      db->aDb[i].pVTable = 0;
    }
  }
  for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
    Module *pMod = (Module *)sqliteHashData(p);
    if( pMod->pEpoTab ){
      sqlite3VtabDisconnect(db, pMod->pEpoTab);
    }

struct Db {
  char *zDbSName;      /* Name of this database. (schema name, not filename) */
  Btree *pBt;          /* The B*Tree structure for this database file */
  u8 safety_level;     /* How aggressive at syncing data to disk */
  u8 bSyncSet;         /* True if "PRAGMA synchronous=N" has been run */
  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
  SchemaPool *pSPool;  /* For REUSE_SCHEMA mode */
  VTable *pVTable;     /* List of all VTable objects (REUSE_SCHEMA mode only) */
};

/*
** An instance of the following structure stores a database schema.
**
** Most Schema objects are associated with a Btree.  The exception is
** the Schema for the TEMP databaes (sqlite3.aDb[1]) which is free-standing.

  sqlite3 *db;              /* Database connection associated with this table */
  Module *pMod;             /* Pointer to module implementation */
  sqlite3_vtab *pVtab;      /* Pointer to vtab instance */
  int nRef;                 /* Number of pointers to this structure */
  u8 bConstraint;           /* True if constraints are supported */
  int iSavepoint;           /* Depth of the SAVEPOINT stack */
  VTable *pNext;            /* Next in linked list (see above) */
  char *zName;              /* Table name (REUSE_SCHEMA mode) */
};

/*
** The schema for each SQL table and view is represented in memory
** by an instance of the following structure.
*/
struct Table {

** pTab is a pointer to a Table structure representing a virtual-table.
** Return a pointer to the VTable object used by connection db to access 
** this virtual-table, if one has been created, or NULL otherwise.
*/
VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
  VTable *pVtab;
  assert( IsVirtual(pTab) );
  if( IsReuseSchema(db) ){
    int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
    if( iDb!=1 ){
      for(pVtab=db->aDb[iDb].pVTable; pVtab; pVtab=pVtab->pNext){
        if( sqlite3StrICmp(pTab->zName, pVtab->zName)==0 ) break;
      }
      return pVtab;
    }
  }
  for(pVtab=pTab->pVTable; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
  return pVtab;
}

/*
** Decrement the ref-count on a virtual table object. When the ref-count
** reaches zero, call the xDisconnect() method to delete the object.

  int rc;
  const char *const*azArg = (const char *const*)pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = 0;
  char *zModuleName;
  int iDb;
  VtabCtx *pCtx;
  int nByte;                      /* Bytes of space to allocate */

  /* Check that the virtual-table is not already being initialized */
  for(pCtx=db->pVtabCtx; pCtx; pCtx=pCtx->pPrior){
    if( pCtx->pTab==pTab ){
      *pzErr = sqlite3MPrintf(db, 
          "vtable constructor called recursively: %s", pTab->zName
      );
      return SQLITE_LOCKED;
    }
  }

  zModuleName = sqlite3DbStrDup(db, pTab->zName);
  if( !zModuleName ){
    return SQLITE_NOMEM_BKPT;
  }

  nByte = sizeof(VTable) + sqlite3Strlen30(pTab->zName) + 1;
  pVTable = (VTable*)sqlite3MallocZero(nByte);
  if( !pVTable ){
    sqlite3OomFault(db);
    sqlite3DbFree(db, zModuleName);
    return SQLITE_NOMEM_BKPT;
  }
  pVTable->db = db;
  pVTable->pMod = pMod;
  pVTable->zName = (char*)&pVTable[1];
  memcpy(pVTable->zName, pTab->zName, nByte-sizeof(VTable));

  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  pTab->azModuleArg[1] = db->aDb[iDb].zDbSName;

  /* Invoke the virtual table constructor */
  assert( &db->pVtabCtx );
  assert( xConstruct );

      *pzErr = sqlite3MPrintf(db, zFormat, pTab->zName);
      sqlite3VtabUnlock(pVTable);
      rc = SQLITE_ERROR;
    }else{
      int iCol;
      u8 oooHidden = 0;
      /* If everything went according to plan, link the new VTable structure
      ** into the linked list headed by pTab->pVTable. Or, if this is a
      ** reusable schema, into the linked list headed by Db.pVTable.
      **
      ** Then loop through the columns of the table to see if any of them
      ** contain the token "hidden". If so, set the Column COLFLAG_HIDDEN flag
      ** and remove the token from the type string.  */
      if( IsReuseSchema(db) && iDb!=1 ){
        pVTable->pNext = db->aDb[iDb].pVTable;
        db->aDb[iDb].pVTable = pVTable;
      }else{
        pVTable->pNext = pTab->pVTable;
        pTab->pVTable = pVTable;
      }

      for(iCol=0; iCol<pTab->nCol; iCol++){
        char *zType = sqlite3ColumnType(&pTab->aCol[iCol], "");
        int nType;
        int i = 0;
        nType = sqlite3Strlen30(zType);
        for(i=0; i<nType; i++){

#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix reuse2


do_execsql_test 1.0 {
  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
  CREATE INDEX i1 ON t1(z);
  PRAGMA schema_version;
} {2}

do_test 1.2 {

do_execsql_test -db db2 1.3.2 {
  INSERT INTO t1 VALUES(4, 5, 6);
}

do_execsql_test 1.3.3 {
  SELECT * FROM t1;
} {1 2 3 4 5 6}

#--------------------------------------------------------------------------
reset_db
ifcapable fts5 {
  do_execsql_test 2.0 {
    CREATE VIRTUAL TABLE ft USING fts5(c);
    INSERT INTO ft VALUES('one two three');
  }
  db close
  sqlite3 db test.db -reuse-schema 1

  do_execsql_test 2.1 {
    SELECT * FROM ft
  } {{one two three}}
}

finish_test