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The invariant of write-ahead logging is that before any change to a page is written to the data file, the corresponding log record must must first have been durably written. In crash recovery, there were some sloppy checks for this. Let us implement accurate checks and flag an inconsistency as a hard error, so that we can avoid further corruption of a corrupted database. For data extraction from the corrupted database, innodb_force_recovery can be used. Before recovery is reading any data pages or invoking buf_dblwr_t::recover() to recover torn pages from the doublewrite buffer, InnoDB will have parsed the log until the final LSN and updated log_sys.lsn to that. So, we can rely on log_sys.lsn at all times. The doublewrite buffer recovery has been refactored in such a way that the recv_sys.dblwr.pages may be consulted while discovering files and their page sizes, but nothing will be written back to data files before buf_dblwr_t::recover() is invoked. recv_max_page_lsn, recv_lsn_checks_on: Remove. recv_sys_t::validate_checkpoint(): Validate the write-ahead-logging condition at the end of the recovery. recv_dblwr_t::validate_page(): Keep track of the maximum LSN (if we are checking a non-doublewrite copy of a page) but do not complain LSN being in the future. The doublewrite buffer is a special case, because it will be read early during recovery. Besides, starting with commit 762bcb81b5bf9bbde61fed59afb26417f4ce1e86 the dblwr=true copies of pages may legitimately be "too new". recv_dblwr_t::find_page(): Find a valid page with the smallest FIL_PAGE_LSN that is in the valid range for recovery. recv_dblwr_t::restore_first_page(): Replaced by find_page(). Only buf_dblwr_t::recover() will write to data files. buf_dblwr_t::recover(): Simplify the message output. Do attempt doublewrite recovery on user page read error. Ignore doublewrite pages whose FIL_PAGE_LSN is outside the usable bounds. Previously, we could wrongly recover a too new page from the doublewrite buffer. It is unlikely that this could have lead to an actual error. Write back all recovered pages from the doublewrite buffer here, including for the first page of any tablespace. buf_page_is_corrupted(): Distinguish the return values CORRUPTED_FUTURE_LSN and CORRUPTED_OTHER. buf_page_check_corrupt(): Return the error code DB_CORRUPTION in case the LSN is in the future. Datafile::read_first_page_flags(): Split from read_first_page(). Take a copy of the first page as a parameter. recv_sys_t::free_corrupted_page(): Take the file as a parameter and return whether a message was displayed. This avoids some duplicated and incomplete error messages. buf_page_t::read_complete(): Remove some redundant output and always display the name of the corrupted file. Never return DB_FAIL; use it only in internal error handling. IORequest::read_complete(): Assume that buf_page_t::read_complete() will have reported any error. fil_space_t::set_corrupted(): Return whether this is the first time the tablespace had been flagged as corrupted. Datafile::validate_first_page(), fil_node_open_file_low(), fil_node_open_file(), fil_space_t::read_page0(), fil_node_t::read_page0(): Add a parameter for a copy of the first page, and a parameter to indicate whether the FIL_PAGE_LSN check should be suppressed. Before buf_dblwr_t::recover() is invoked, we cannot validate the FIL_PAGE_LSN, but we can trust the FSP_SPACE_FLAGS and the tablespace ID that may be present in a potentially too new copy of a page. Reviewed by: Debarun Banerjee
20 lines
852 B
Plaintext
20 lines
852 B
Plaintext
call mtr.add_suppression("Checksum mismatch in the first page of file");
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show variables like 'innodb_doublewrite';
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Variable_name Value
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innodb_doublewrite ON
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create table t1(f1 int not null, f2 int not null)engine=innodb;
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insert into t1 values (1, 1);
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SET GLOBAL innodb_fast_shutdown = 0;
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# restart: --debug_dbug=+d,ib_log_checkpoint_avoid_hard --innodb_flush_sync=0
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# Make the first page dirty for undo tablespace
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set global innodb_saved_page_number_debug = 0;
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set global innodb_fil_make_page_dirty_debug = 1;
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SET GLOBAL innodb_buf_flush_list_now = 1;
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# Kill the server
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# restart: --debug_dbug=+d,ib_log_checkpoint_avoid_hard --innodb_flush_sync=0
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FOUND 1 /Recovered page \[page id: space=1, page number=0\] to '.*undo001' from the doublewrite buffer\./ in mysqld.1.err
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check table t1;
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Table Op Msg_type Msg_text
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test.t1 check status OK
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drop table t1;
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