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| 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 | |
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