mirror of
https://github.com/MariaDB/server.git
synced 2025-01-31 11:01:52 +01:00
50077b6db9
The problem in this bug is when we create temporary tables. When temporary tables are created for unions, there is some inferrence being carried out regarding the type of the column. Whenever this column type is inferred to be REAL (i.e. FLOAT or DOUBLE), MySQL will always try to maintain exact precision, and if that is not possible (there are hardware limits, since FLOAT and DOUBLE are stored as approximate values) will switch to using approximate values. The problem here is that at this point the information about number of significant digits is not available. Furthermore, the number of significant digits should be increased for the AVG function, however, this was not properly handled. There are 4 parts to the problem: #1: DOUBLE and FLOAT fields don't display their proper display lengths in max_display_length(). This is hard-coded as 53 for DOUBLE and 24 for FLOAT. Now changed to instead return the field_length. #2: Type holders for temporary tables do not preserve the max_length of the Item's from which they are created, and is instead reverted to the 53 and 24 from above. This causes *all* fields to get non-fixed significant digits. #3: AVG function does not update max_length (display length) when updating number of decimals. #4: The function that switches to non-fixed number of significant digits should use DBL_DIG + 2 or FLT_DIG + 2 as cut-off values (Since fixed precision does not use the 'e' notation) Of these points, #1 is the controversial one, but this change is preferred and has been cleared with Monty. The function causes quite a few unit tests to blow up and they had to b changed, but each one is annotated and motivated. We frequently see the magical 53 and 24 give way to more relevant numbers. |
||
|---|---|---|
| .. | ||
| include | ||
| lib | ||
| misc | ||
| ndb | ||
| r | ||
| std_data | ||
| suite | ||
| t | ||
| create-test-result | ||
| fix-result | ||
| install_test_db.sh | ||
| Makefile.am | ||
| mysql-stress-test.pl | ||
| mysql-test-run-shell.sh | ||
| mysql-test-run.pl | ||
| purify.supp | ||
| README | ||
| README.gcov | ||
| README.stress | ||
| resolve-stack | ||
| 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