SQLite

  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_DEBUG
  u8 lockError;              /* True if a locking error has occurred */
#endif
#ifdef SQLITE_ENABLE_SNAPSHOT
  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
#endif
  int bClosing;              /* Set to true at start of sqlite3WalClose() */
  int bWal2;                 /* bWal2 flag passed to WalOpen() */
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  sqlite3 *db;
#endif
};

/*

  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
  int nBuf,
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */
    pWal->bClosing = 1;

    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **

        }else{
          *pnCkpt = walCkptInfo(pWal)->nBackfill;
        }
      }
    }
  }

  if( isChanged && pWal->bClosing==0 ){
    /* If a new wal-index header was loaded before the checkpoint was 
    ** performed, then the pager-cache associated with pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.
    **
    ** Except, do not do this if the wal is being closed. In this case
    ** the caller needs the wal-index header to check if the database is
    ** in wal2 mode and the "other" wal file also needs to be checkpointed.
    ** Besides, the pager cache will not be used again in this case. */
    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
  }

  walDisableBlocking(pWal);
  sqlite3WalDb(pWal, 0);

  /* Release the locks. */

# 2017 September 19
#
# 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.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

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

set testprefix wal2openclose
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  PRAGMA journal_mode = wal2;
  PRAGMA wal_autocheckpoint = 0;
  PRAGMA journal_size_limit = 75000;
} {wal2 0 75000}

do_test 1.1 {
  for {set ii 1} {$ii <= 200} {incr ii} {
    execsql {
      INSERT INTO t1 VALUES($ii, $ii, $ii);
    }
  }
  expr ([file size test.db-wal2] - 75000) > 30000
} {1}

do_test 1.2 {
  db close
  list [file exists test.db-wal] [file exists test.db-wal2]
} {0 0}

sqlite3 db test.db
do_execsql_test 1.3 {
  SELECT sum(c) FROM t1
} {20100}
db close

#-------------------------------------------------------------------------
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(a, b, c);
  PRAGMA journal_mode = wal2;
  INSERT INTO t1 VALUES(1, 2, 3);
} {wal2}
db_save_and_close

db_restore_and_reopen
do_execsql_test 2.1 {
  SELECT * FROM t1;
} {1 2 3}

do_test 2.2 {
  sqlite3 db2 test.db
  db2 eval {INSERT INTO t1 VALUES(4, 5, 6)}
  db2 close
} {}

breakpoint
db close
sqlite3 db test.db
do_execsql_test 2.2 {
  SELECT * FROM t1;
} {1 2 3 4 5 6}



finish_test

    INSERT INTO t1 VALUES(randomblob(500));
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 3176 12288}
do_test 7.3.2 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 3176 22528}
do_test 7.3.3 {
  execsql { 
    INSERT INTO t1 VALUES(randomblob(10000));
    INSERT INTO t1 VALUES(randomblob(500));
  }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 18896 22528}
do_test 7.3.4 {
  execsql END db2
  execsql { INSERT INTO t1 VALUES(randomblob(5000)); }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 18896 22528}

# Connection db2 is holding a PART2 lock. 
#
#   7.4.2: Test that the lock does not prevent writer switching to test.db-wal.
#
#   7.3.3: Test that the lock does prevent checkpointing of test.db-wal2.
#

    PRAGMA wal_checkpoint;
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.2 {
  execsql { 
    INSERT INTO t1 VALUES(randomblob(5000));
  }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.3 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.4 {
  execsql END db2
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 60416}

# Connection db2 is holding a PART1_FULL2 lock. 
#
#   7.5.2: Test that the lock does not prevent a checkpoint of test.db-wal2.
#
#   7.5.3: Test that the lock does prevent the writer from overwriting
#          test.db-wal2.

    INSERT INTO t1 VALUES(randomblob(5000));
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 76800}
do_test 7.5.2 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 87040}
do_test 7.5.3.1 {
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {14704 12608 87040}
do_test 7.5.3.2 {
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {22040 12608 87040}
do_test 7.5.4 {
  execsql END db2
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {22040 12608 87040}


finish_test