Return to walcrash2.test CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / sqlite3 / test

sqlite3

    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: