SQLite

            }else if( sqlite3BitvecTestNotNull(pAllRead, aPgno[i]) ){
              sqlite3_log(SQLITE_OK,
                  "cannot commit UNLOCKED transaction (conflict at page %d)",
                  (int)aPgno[i]
              );
              rc = SQLITE_BUSY_SNAPSHOT;
            }else if( (pPg = sqlite3PagerLookup(pPager, aPgno[i])) ){
              /* Page aPgno[i], which is present in the pager cache, has been
              ** modified since the current UNLOCKED transaction was started.
              ** However it was not read by the current transaction, so is not
              ** a conflict. There are two possibilities: (a) the page was
              ** allocated at the of the file by the current transaction or 
              ** (b) was present in the cache at the start of the transaction.
              **
              ** For case (a), do nothing. This page will be moved within the
              ** database file by the commit code to avoid the conflict. The
              ** call to PagerUnref() is to release the reference grabbed by
              ** the sqlite3PagerLookup() above.  
              **
              ** In case (b), drop the page from the cache - otherwise
              ** following the snapshot upgrade the cache would be inconsistent
              ** with the database as stored on disk. */
              if( sqlite3PagerIswriteable(pPg) ){
                sqlite3PagerUnref(pPg);
              }else{
                sqlite3PcacheDrop(pPg);
              }
            }
          }
        }
        if( rc!=SQLITE_OK ) break;
      }
    }

    sql1 COMMIT
  } {}

  do_test 2.$tn.7 { sql3 { PRAGMA integrity_check } } {ok}
}

#-------------------------------------------------------------------------
# When an UNLOCKED transaction is opened on a database, the nFree and 
# iTrunk header fields of the cached version of page 1 are both set 
# to 0. This allows an UNLOCKED transaction to use its own private 
# free-page-list, which is merged with the main database free-list when
# the transaction is committed.
#
# The following tests check that nFree/iTrunk are correctly restored if
# an UNLOCKED transaction is rolled back, and that savepoint rollbacks
# that occur within UNLOCKED transactions do not incorrectly restore
# these fields to their on-disk values.
#
reset_db
do_execsql_test 3.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(x, y);
  INSERT INTO t1 VALUES(randomblob(1500), randomblob(1500));
  DELETE FROM t1;
} {wal}





do_execsql_test 3.1 {
  BEGIN UNLOCKED;
    INSERT INTO t1 VALUES(1, 2);
  ROLLBACK;
}

do_execsql_test 3.2 { PRAGMA integrity_check } {ok}
do_execsql_test 3.3 { PRAGMA freelist_count } {2}

do_execsql_test 3.4.1 {
  BEGIN UNLOCKED;
    PRAGMA freelist_count;
} {2}
do_execsql_test 3.4.2 {
  SAVEPOINT xyz;
    INSERT INTO t1 VALUES(randomblob(1500), NULL);
    PRAGMA freelist_count;
} {0}
do_execsql_test 3.4.3 {
  ROLLBACK TO xyz;
} {}
do_execsql_test 3.4.4 { PRAGMA freelist_count } {0}
do_execsql_test 3.4.5 { COMMIT; PRAGMA freelist_count } {2}
do_execsql_test 3.4.6 { PRAGMA integrity_check } {ok}

do_execsql_test 3.5.1 {
  BEGIN UNLOCKED;
    UPDATE t1 SET x=randomblob(10) WHERE y=555;
    PRAGMA freelist_count;
} {0}
do_execsql_test 3.5.2 {
  ROLLBACK;
  PRAGMA freelist_count;
} {2}
do_execsql_test 3.5.3 { PRAGMA integrity_check } {ok}

finish_test