SQLite

    }

    /* If more than one frame was recovered from the log file, report an
    ** event via sqlite3_log(). This is to help with identifying performance
    ** problems caused by applications routinely shutting down without
    ** checkpointing the log file.  */
    if( pWal->hdr.nPage ){
      if( isWalMode2(pWal) ){
        sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
            "recovered (%d,%d) frames from WAL files %s[2] (%s mode)",
            walidxGetMxFrame(&pWal->hdr, 0), walidxGetMxFrame(&pWal->hdr, 1), 
            pWal->zWalName, isWalMode2(pWal) ? "wal2" : "wal"
        );
      }else{
        sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
            "recovered %d frames from WAL file %s",
            pWal->hdr.mxFrame, pWal->zWalName
        );
      }
    }
  }

  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
  walUnlockExclusive(pWal, iLock, nLock);
  return rc;
}

        testcase( IS_BIG_INT(iOffset) );
        rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
        if( rc!=SQLITE_OK ) break;
      }

      /* Truncate the db file, sync the wal file and set the WalCkptInfo
      ** flag to indicate that it has been checkpointed. */
      if( rc==SQLITE_OK && (bWal2 || mxSafeFrame==walIndexHdr(pWal)->mxFrame) ){
        if( !bWal2 ){
          i64 szDb = pWal->hdr.nPage*(i64)szPage;
          testcase( IS_BIG_INT(szDb) );
          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
        }
        if( rc==SQLITE_OK ){
          rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
        }
      }
      if( rc==SQLITE_OK ){
        pInfo->nBackfill = bWal2 ? 1 : mxSafeFrame;
      }

      /* Release the reader lock held while backfilling */
      walUnlockExclusive(pWal, WAL_READ_LOCK(bWal2 ? 1 + iCkpt*2 : 0), 1);

  ** upgrade to exclusive-mode following such an error.
  */
  assert( pWal->readLock!=WAL_LOCK_NONE || pWal->lockError );
  assert( pWal->readLock!=WAL_LOCK_NONE || (op<=0 && pWal->exclusiveMode==0) );

  if( op==0 ){
    if( pWal->exclusiveMode ){
      pWal->exclusiveMode = WAL_NORMAL_MODE;
      if( isWalMode2(pWal) ){
        rc = walLockReader(pWal, pWal->readLock, 1);
      }else{
        rc = walLockShared(pWal, WAL_READ_LOCK(pWal->readLock));
      }
      if( rc!=SQLITE_OK ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = pWal->exclusiveMode==0;
    }else{
      /* Already in locking_mode=NORMAL */
      rc = 0;
    }
  }else if( op>0 ){
    assert( pWal->exclusiveMode==0 );
    assert( pWal->readLock>=0 );
    if( isWalMode2(pWal) ){
      walLockReader(pWal, pWal->readLock, 0);
    }else{
      walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
    }
    pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
    rc = 1;
  }else{
    rc = pWal->exclusiveMode==0;
  }
  return rc;
}

# Corrupt the file header in various ways and make sure the corruption
# is detected when opening the database file.
#
db close
forcecopy test.db test.db-template

set unreadable_version 02
ifcapable wal { set unreadable_version 04 }
do_test corruptA-2.1 {
  forcecopy test.db-template test.db
  hexio_write test.db 19 $unreadable_version   ;# the read format number
  sqlite3 db test.db
  catchsql {SELECT * FROM t1}  
} {1 {file is not a database}}
 

# returns 1 if the database N of connection D is read-only, 0 if it is
# read/write, or -1 if N is not the name of a database on connection D.
#
do_test rdonly-1.1.1 {
  sqlite3_db_readonly db main
} {0}

# Changes the write version from 1 to 4.  Verify that the database
# can be read but not written.
#
do_test rdonly-1.2 {
  db close
  hexio_get_int [hexio_read test.db 18 1]
} 1
do_test rdonly-1.3 {
  hexio_write test.db 18 04
  sqlite3 db test.db
  execsql {
    SELECT * FROM t1;
  }
} {1}
do_test rdonly-1.3.1 {
  sqlite3_db_readonly db main

# Now, after connection [db] has loaded the database schema, modify the
# write-version of the file (and the change-counter, so that the 
# write-version is reloaded). This way, SQLite does not discover that
# the database is read-only until after it is locked.
#
set ro_version 02
ifcapable wal { set ro_version 04 }
do_test rdonly-1.6 {
  hexio_write test.db 18 $ro_version     ; # write-version
  hexio_write test.db 24 11223344        ; # change-counter
  catchsql {
    INSERT INTO t1 VALUES(2);
  }
} {1 {attempt to write a readonly database}}

finish_test

      CREATE TABLE aux.t2(a, b);
      PRAGMA main.journal_mode = WAL;
      PRAGMA aux.journal_mode = WAL;
      INSERT INTO t1 VALUES('x', 'y');
      INSERT INTO t2 VALUES('x', 'y');
    }
    lsort [array names ::T1]
  } {test.db1 test.db1-journal test.db1-wal test.db1-wal2}
  
  do_test 5.1.2 {
    lsort [array names ::T2]
  } {test.db2 test.db2-journal test.db2-wal test.db2-wal2}
  db close
  
  tvfs1 delete
  tvfs2 delete
}

#-------------------------------------------------------------------------