99 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			99 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| # 2010 May 25
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| #
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| # The author disclaims copyright to this source code.  In place of
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| # a legal notice, here is a blessing:
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| #
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| #    May you do good and not evil.
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| #    May you find forgiveness for yourself and forgive others.
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| #    May you share freely, never taking more than you give.
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| #
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| #***********************************************************************
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| #
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| 
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| 
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| set testdir [file dirname $argv0]
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| source $testdir/tester.tcl
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| source $testdir/lock_common.tcl
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| source $testdir/wal_common.tcl
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| ifcapable !wal {finish_test ; return }
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| 
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| 
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| #-------------------------------------------------------------------------
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| # This test case demonstrates a flaw in the wal-index manipulation that
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| # existed at one point: If a process crashes mid-transaction, it may have
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| # already added some entries to one of the hash-tables in the wal-index.
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| # If the transaction were to be explicitly rolled back at this point, the
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| # hash-table entries would be removed as part of the rollback. However,
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| # if the process crashes, the transaction is implicitly rolled back and
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| # the rogue entries remain in the hash table.
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| #
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| # Normally, this causes no problem - readers can tell the difference 
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| # between committed and uncommitted entries in the hash table. However,
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| # if it happens often enough that all slots in the hash-table become 
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| # non-zero, the next process that attempts to read or write the hash
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| # table falls into an infinite loop.
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| #
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| # Even if run with an SQLite version affected by the bug, this test case
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| # only goes into an infinite loop if SQLite is compiled without SQLITE_DEBUG
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| # defined. If SQLITE_DEBUG is defined, the program is halted by a failing
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| # assert() before entering the infinite loop.
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| #
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| # walcrash2-1.1: Create a database. Commit a transaction that adds 8 frames
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| #                to the WAL (and 8 entry to the first hash-table in the 
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| #                wal-index).
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| #
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| # walcrash2-1.2: Have an external process open a transaction, add 8 entries
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| #                to the wal-index hash-table, then crash. Repeat this 1023
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| #                times (so that the wal-index contains 8192 entries - all
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| #                slots are non-zero).
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| #
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| # walcrash2-1.3: Using a new database connection, attempt to query the 
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| #                database. This should cause the process to go into the
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| #                infinite loop.
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| #
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| do_test walcrash2-1.1 {
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|   execsql {
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|     PRAGMA page_size = 1024;
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|     PRAGMA auto_vacuum = off;
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|     PRAGMA journal_mode = WAL;
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|     PRAGMA synchronous = NORMAL;
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|     BEGIN;
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|       CREATE TABLE t1(x);
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|       CREATE TABLE t2(x);
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|       CREATE TABLE t3(x);
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|       CREATE TABLE t4(x);
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|       CREATE TABLE t5(x);
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|       CREATE TABLE t6(x);
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|       CREATE TABLE t7(x);
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|     COMMIT;
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|   }
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|   file size test.db-wal
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| } [wal_file_size 8 1024] 
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| for {set nEntry 8} {$nEntry < 8192} {incr nEntry 8} {
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|   do_test walcrash2-1.2.[expr $nEntry/8] {
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|     set C [launch_testfixture]
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|     testfixture $C {
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|       sqlite3 db test.db
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|       db eval {
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|         PRAGMA cache_size = 15;
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|         BEGIN;
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|           INSERT INTO t1 VALUES(randomblob(900));         --  1 row,  1  page
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|           INSERT INTO t1 SELECT * FROM t1;                --  2 rows, 3  pages
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|           INSERT INTO t1 SELECT * FROM t1;                --  4 rows, 5  pages
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|           INSERT INTO t1 SELECT * FROM t1;                --  8 rows, 9  pages
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|           INSERT INTO t1 SELECT * FROM t1;                -- 16 rows, 17 pages
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|           INSERT INTO t1 SELECT * FROM t1 LIMIT 3;        -- 20 rows, 20 pages
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|       }
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|     } 
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|     close $C
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|     file size test.db-wal
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|   } [wal_file_size 16 1024]
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| }
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| do_test walcrash2-1.3 {
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|   sqlite3 db2 test.db
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|   execsql { SELECT count(*) FROM t1 } db2
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| } {0}
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| catch { db2 close }
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| 
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| finish_test
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