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Annotation of embedaddon/sqlite3/test/walcrash2.test, revision 1.1

1.1     ! misho       1: # 2010 May 25
        !             2: #
        !             3: # The author disclaims copyright to this source code.  In place of
        !             4: # a legal notice, here is a blessing:
        !             5: #
        !             6: #    May you do good and not evil.
        !             7: #    May you find forgiveness for yourself and forgive others.
        !             8: #    May you share freely, never taking more than you give.
        !             9: #
        !            10: #***********************************************************************
        !            11: #
        !            12: 
        !            13: 
        !            14: set testdir [file dirname $argv0]
        !            15: source $testdir/tester.tcl
        !            16: source $testdir/lock_common.tcl
        !            17: source $testdir/wal_common.tcl
        !            18: ifcapable !wal {finish_test ; return }
        !            19: 
        !            20: 
        !            21: #-------------------------------------------------------------------------
        !            22: # This test case demonstrates a flaw in the wal-index manipulation that
        !            23: # existed at one point: If a process crashes mid-transaction, it may have
        !            24: # already added some entries to one of the hash-tables in the wal-index.
        !            25: # If the transaction were to be explicitly rolled back at this point, the
        !            26: # hash-table entries would be removed as part of the rollback. However,
        !            27: # if the process crashes, the transaction is implicitly rolled back and
        !            28: # the rogue entries remain in the hash table.
        !            29: #
        !            30: # Normally, this causes no problem - readers can tell the difference 
        !            31: # between committed and uncommitted entries in the hash table. However,
        !            32: # if it happens often enough that all slots in the hash-table become 
        !            33: # non-zero, the next process that attempts to read or write the hash
        !            34: # table falls into an infinite loop.
        !            35: #
        !            36: # Even if run with an SQLite version affected by the bug, this test case
        !            37: # only goes into an infinite loop if SQLite is compiled without SQLITE_DEBUG
        !            38: # defined. If SQLITE_DEBUG is defined, the program is halted by a failing
        !            39: # assert() before entering the infinite loop.
        !            40: #
        !            41: # walcrash2-1.1: Create a database. Commit a transaction that adds 8 frames
        !            42: #                to the WAL (and 8 entry to the first hash-table in the 
        !            43: #                wal-index).
        !            44: #
        !            45: # walcrash2-1.2: Have an external process open a transaction, add 8 entries
        !            46: #                to the wal-index hash-table, then crash. Repeat this 1023
        !            47: #                times (so that the wal-index contains 8192 entries - all
        !            48: #                slots are non-zero).
        !            49: #
        !            50: # walcrash2-1.3: Using a new database connection, attempt to query the 
        !            51: #                database. This should cause the process to go into the
        !            52: #                infinite loop.
        !            53: #
        !            54: do_test walcrash2-1.1 {
        !            55:   execsql {
        !            56:     PRAGMA page_size = 1024;
        !            57:     PRAGMA auto_vacuum = off;
        !            58:     PRAGMA journal_mode = WAL;
        !            59:     PRAGMA synchronous = NORMAL;
        !            60:     BEGIN;
        !            61:       CREATE TABLE t1(x);
        !            62:       CREATE TABLE t2(x);
        !            63:       CREATE TABLE t3(x);
        !            64:       CREATE TABLE t4(x);
        !            65:       CREATE TABLE t5(x);
        !            66:       CREATE TABLE t6(x);
        !            67:       CREATE TABLE t7(x);
        !            68:     COMMIT;
        !            69:   }
        !            70:   file size test.db-wal
        !            71: } [wal_file_size 8 1024] 
        !            72: for {set nEntry 8} {$nEntry < 8192} {incr nEntry 8} {
        !            73:   do_test walcrash2-1.2.[expr $nEntry/8] {
        !            74:     set C [launch_testfixture]
        !            75:     testfixture $C {
        !            76:       sqlite3 db test.db
        !            77:       db eval {
        !            78:         PRAGMA cache_size = 15;
        !            79:         BEGIN;
        !            80:           INSERT INTO t1 VALUES(randomblob(900));         --  1 row,  1  page
        !            81:           INSERT INTO t1 SELECT * FROM t1;                --  2 rows, 3  pages
        !            82:           INSERT INTO t1 SELECT * FROM t1;                --  4 rows, 5  pages
        !            83:           INSERT INTO t1 SELECT * FROM t1;                --  8 rows, 9  pages
        !            84:           INSERT INTO t1 SELECT * FROM t1;                -- 16 rows, 17 pages
        !            85:           INSERT INTO t1 SELECT * FROM t1 LIMIT 3;        -- 20 rows, 20 pages
        !            86:       }
        !            87:     } 
        !            88:     close $C
        !            89:     file size test.db-wal
        !            90:   } [wal_file_size 16 1024]
        !            91: }
        !            92: do_test walcrash2-1.3 {
        !            93:   sqlite3 db2 test.db
        !            94:   execsql { SELECT count(*) FROM t1 } db2
        !            95: } {0}
        !            96: catch { db2 close }
        !            97: 
        !            98: finish_test
        !            99: