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The fix of Bug#12612184 broke crash recovery. When a record that contains off-page columns (BLOBs) is updated, we must first write redo log about the BLOB page writes, and only after that write the redo log about the B-tree changes. The buggy fix would log the B-tree changes first, meaning that after recovery, we could end up having a record that contains a null BLOB pointer. Because we will be redo logging the writes off the off-page columns before the B-tree changes, we must make sure that the pages chosen for the off-page columns are free both before and after the B-tree changes. In this way, the worst thing that can happen in crash recovery is that the BLOBs are written to free pages, but the B-tree changes are not applied. The BLOB pages would correctly remain free in this case. To achieve this, we must allocate the BLOB pages in the mini-transaction of the B-tree operation. A further quirk is that BLOB pages are allocated from the same file segment as leaf pages. Because of this, we must temporarily "hide" any leaf pages that were freed during the B-tree operation by "fake allocating" them prior to writing the BLOBs, and freeing them again before the mtr_commit() of the B-tree operation, in btr_mark_freed_leaves(). btr_cur_mtr_commit_and_start(): Remove this faulty function that was introduced in the Bug#12612184 fix. The problem that this function was trying to address was that when we did mtr_commit() the BLOB writes before the mtr_commit() of the update, the new BLOB pages could have overwritten clustered index B-tree leaf pages that were freed during the update. If recovery applied the redo log of the BLOB writes but did not see the log of the record update, the index tree would be corrupted. The correct solution is to make the freed clustered index pages unavailable to the BLOB allocation. This function is also a likely culprit of InnoDB hangs that were observed when testing the Bug#12612184 fix. btr_mark_freed_leaves(): Mark all freed clustered index leaf pages of a mini-transaction allocated (nonfree=TRUE) before storing the BLOBs, or freed (nonfree=FALSE) before committing the mini-transaction. btr_freed_leaves_validate(): A debug function for checking that all clustered index leaf pages that have been marked free in the mini-transaction are consistent (have not been zeroed out). btr_page_alloc_low(): Refactored from btr_page_alloc(). Return the number of the allocated page, or FIL_NULL if out of space. Add the parameter "mtr_t* init_mtr" for specifying the mini-transaction where the page should be initialized, or if this is a "fake allocation" (init_mtr=NULL) by btr_mark_freed_leaves(nonfree=TRUE). btr_page_alloc(): Add the parameter init_mtr, allowing the page to be initialized and X-latched in a different mini-transaction than the one that is used for the allocation. Invoke btr_page_alloc_low(). If a clustered index leaf page was previously freed in mtr, remove it from the memo of previously freed pages. btr_page_free(): Assert that the page is a B-tree page and it has been X-latched by the mini-transaction. If the freed page was a leaf page of a clustered index, link it by a MTR_MEMO_FREE_CLUST_LEAF marker to the mini-transaction. btr_store_big_rec_extern_fields_func(): Add the parameter alloc_mtr, which is NULL (old behaviour in inserts) and the same as local_mtr in updates. If alloc_mtr!=NULL, the BLOB pages will be allocated from it instead of the mini-transaction that is used for writing the BLOBs. fsp_alloc_from_free_frag(): Refactored from fsp_alloc_free_page(). Allocate the specified page from a partially free extent. fseg_alloc_free_page_low(), fseg_alloc_free_page_general(): Add the parameter "mtr_t* init_mtr" for specifying the mini-transaction where the page should be initialized, or NULL if this is a "fake allocation" that prevents the reuse of a previously freed B-tree page for BLOB storage. If init_mtr==NULL, try harder to reallocate the specified page and assert that it succeeded. fsp_alloc_free_page(): Add the parameter "mtr_t* init_mtr" for specifying the mini-transaction where the page should be initialized. Do not allow init_mtr == NULL, because this function is never to be used for "fake allocations". mtr_t: Add the operation MTR_MEMO_FREE_CLUST_LEAF and the flag mtr->freed_clust_leaf for quickly determining if any MTR_MEMO_FREE_CLUST_LEAF operations have been posted. row_ins_index_entry_low(): When columns are being made off-page in insert-by-update, invoke btr_mark_freed_leaves(nonfree=TRUE) and pass the mini-transaction as the alloc_mtr to btr_store_big_rec_extern_fields(). Finally, invoke btr_mark_freed_leaves(nonfree=FALSE) to avoid leaking pages. row_build(): Correct a comment, and add a debug assertion that a record that contains NULL BLOB pointers must be a fresh insert. row_upd_clust_rec(): When columns are being moved off-page, invoke btr_mark_freed_leaves(nonfree=TRUE) and pass the mini-transaction as the alloc_mtr to btr_store_big_rec_extern_fields(). Finally, invoke btr_mark_freed_leaves(nonfree=FALSE) to avoid leaking pages. buf_reset_check_index_page_at_flush(): Remove. The function fsp_init_file_page_low() already sets bpage->check_index_page_at_flush=FALSE. There is a known issue in tablespace extension. If the request to allocate a BLOB page leads to the tablespace being extended, crash recovery could see BLOB writes to pages that are off the tablespace file bounds. This should trigger an assertion failure in fil_io() at crash recovery. The safe thing would be to write redo log about the tablespace extension to the mini-transaction of the BLOB write, not to the mini-transaction of the record update. However, there is no redo log record for file extension in the current redo log format. rb:693 approved by Sunny Bains |
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| 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