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--Bug#52157 various crashes and assertions with multi-table update, stored function --Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb --Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846 --Bug#57352 valgrind warnings when creating view --Recently discovered problem when a nested materialized derived table is used before being populated and it leads to incorrect result We have several modes when we should disable subquery evaluation. The reasons for disabling are different. It could be uselessness of the evaluation as in case of 'CREATE VIEW' or 'PREPARE stmt', or we should disable subquery evaluation if tables are not locked yet as it happens in bug#54475, or too early evaluation of subqueries can lead to wrong result as it happened in Bug#19077. Main problem is that if subquery items are treated as const they are evaluated in ::fix_fields(), ::fix_length_and_dec() of the parental items as a lot of these methods have Item::val_...() calls inside. We have to make subqueries non-const to prevent unnecessary subquery evaluation. At the moment we have different methods for this. Here is a list of these modes: 1. PREPARE stmt; We use UNCACHEABLE_PREPARE flag. It is set during parsing in sql_parse.cc, mysql_new_select() for each SELECT_LEX object and cleared at the end of PREPARE in sql_prepare.cc, init_stmt_after_parse(). If this flag is set subquery becomes non-const and evaluation does not happen. 2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which process FRM files We use LEX::view_prepare_mode field. We set it before view preparation and check this flag in ::fix_fields(), ::fix_length_and_dec(). Some bugs are fixed using this approach, some are not(Bug#57352, Bug#57703). The problem here is that we have a lot of ::fix_fields(), ::fix_length_and_dec() where we use Item::val_...() calls for const items. 3. Derived tables with subquery = wrong result(Bug19077) The reason of this bug is too early subquery evaluation. It was fixed by adding Item::with_subselect field The check of this field in appropriate places prevents const item evaluation if the item have subquery. The fix for Bug19077 fixes only the problem with convert_constant_item() function and does not cover other places(::fix_fields(), ::fix_length_and_dec() again) where subqueries could be evaluated. Example: CREATE TABLE t1 (i INT, j BIGINT); INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2); SELECT * FROM (SELECT MIN(i) FROM t1 WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3; DROP TABLE t1; 4. Derived tables with subquery where subquery is evaluated before table locking(Bug#54475, Bug#52157) Suggested solution is following: -Introduce new field LEX::context_analysis_only with the following possible flags: #define CONTEXT_ANALYSIS_ONLY_PREPARE 1 #define CONTEXT_ANALYSIS_ONLY_VIEW 2 #define CONTEXT_ANALYSIS_ONLY_DERIVED 4 -Set/clean these flags when we perform context analysis operation -Item_subselect::const_item() returns result depending on LEX::context_analysis_only. If context_analysis_only is set then we return FALSE that means that subquery is non-const. As all subquery types are wrapped by Item_subselect it allow as to make subquery non-const when it's necessary. |
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collections | ||
extra | ||
include | ||
lib | ||
r | ||
std_data | ||
suite | ||
t | ||
Makefile.am | ||
mysql-stress-test.pl | ||
mysql-test-run.pl | ||
purify.supp | ||
README | ||
README.gcov | ||
README.stress | ||
valgrind.supp |
This directory contains a test suite for the MySQL daemon. To run the currently existing test cases, simply execute ./mysql-test-run in this directory. It will fire up the newly built mysqld and test it. Note that you do not have to have to do "make install", and you could actually have a co-existing MySQL installation. The tests will not conflict with it. All tests must pass. If one or more of them fail on your system, please read the following manual section for instructions on how to report the problem: http://dev.mysql.com/doc/mysql/en/mysql-test-suite.html If you want to use an already running MySQL server for specific tests, use the --extern option to mysql-test-run. Please note that in this mode, the test suite expects you to provide the names of the tests to run. For example, here is the command to run the "alias" and "analyze" tests with an external server: mysql-test-run --extern alias analyze To match your setup, you might also need to provide --socket, --user, and other relevant options. With no test cases named on the command line, mysql-test-run falls back to the normal "non-extern" behavior. The reason for this is that some tests cannot run with an external server. You can create your own test cases. To create a test case, create a new file in the t subdirectory using a text editor. The file should have a .test extension. For example: xemacs t/test_case_name.test In the file, put a set of SQL statements that create some tables, load test data, and run some queries to manipulate it. We would appreciate it if you name your test tables t1, t2, t3 ... (to not conflict too much with existing tables). Your test should begin by dropping the tables you are going to create and end by dropping them again. This ensures that you can run the test over and over again. If you are using mysqltest commands (like result file names) in your test case, you should create the result file as follows: mysql-test-run --record test_case_name or mysqltest --record < t/test_case_name.test If you only have a simple test cases consisting of SQL statements and comments, you can create the test case in one of the following ways: mysql-test-run --record test_case_name mysql test < t/test_case_name.test > r/test_case_name.result mysqltest --record --record-file=r/test_case_name.result < t/test_case_name.test When this is done, take a look at r/test_case_name.result - If the result is incorrect, you have found a bug. In this case, you should edit the test result to the correct results so that we can verify that the bug is corrected in future releases. To submit your test case, put your .test file and .result file(s) into a tar.gz archive, add a README that explains the problem, ftp the archive to ftp://support.mysql.com/pub/mysql/secret/ and send a mail to bugs@lists.mysql.com