- Because my_seek actually is capable of returning an error code we should
exploit that in the best possible way.
- There might be kernel errors or other errors we can't predict and capturing
the return value of all system calls gives us better understanding of
possible errors.
- The io cache flag seek_not_done was not set properly in the reinit_
io_chache function call and this led my_seek to be called despite an
invalid file handle.
- Added a test in reinit_io_cache to ensure we have a valid file handle
before setting seek_not_done flag.
OPTIMIZE TABLE with myisam_repair_threads > 1 performs a non-quick
parallel repair. This means that it does not only rebuild all
indexes, but also the data file.
Non-quick parallel repair works so that there is one thread per
index. The first of the threads rebuilds also the new data file.
The problem was that all threads shared the read io cache on the
old data file. If there were holes (deleted records) in the table,
the first thread skipped them, writing only contiguous, non-deleted
records to the new data file. Then it built the new index so that
its entries pointed to the correct record positions. But the other
threads didn't know the new record positions, but put the positions
from the old data file into the index.
The new design is so that there is a shared io cache which is filled
by the first thread (the data file writer) with the new contiguous
records and read by the other threads. Now they know the new record
positions.
Another problem was that for the parallel repair of compressed
tables a common bit_buff and rec_buff was used. I changed it so
that thread specific buffers are used for parallel repair.
A similar problem existed for checksum calculation. I made this
multi-thread safe too.
crash for, e.g., NDB):
Before, mysqlbinlog printed table map events as a separate statement, so
when executing the event, the opened table was subsequently closed
when the statement ended. Instead, the row-based events that make up
a statement are now printed as *one* BINLOG statement, which means
that the table maps and the following *_rows_log_event events are
executed fully before the statement ends.
Changing implementation of BINLOG statement to be able to read the
emitted format, which now consists of several chunks of BASE64-encoded
data.
Crash may happen when selecting from a merge table that has underlying
tables with less indexes than in a merge table itself.
If number of keys in merge table is not bigger than requested key number,
return error.
- Fix my_read/my_write to handle return values from read/write correctly
- Add debugging 'deprecated function' warning to my_lread/my_lwrite
- Add debugging 'error, read/write interrupt not handled' warning to my_quick_read/my_quick_write
There is no test case associated with these changes. However, this is a conservative change,
and no repeatable test case is available.
