(back to behaviour of 4.1.7). Warning was not fatal: mysqldump continued. And the good thing is that it helped spot that starting from 4.1.7,
SHOW CREATE DATABASE failed (if --single-transaction and first db has non-empty InnoDB table and there is a second db) and thus mysqldump
produced CREATE DATABASE statements missing the CHARACTER SET clause. Removing the bug which was in the server, and the warning reporting in
mysqldump (compatibility with old servers).
Renamed HA_VAR_LENGTH to HA_VAR_LENGTH_PART
Renamed in all files FIELD_TYPE_STRING and FIELD_TYPE_VAR_STRING to MYSQL_TYPE_STRING and MYSQL_TYPE_VAR_STRING to make it easy to catch all possible errors
Added support for VARCHAR KEYS to heap
Removed support for ISAM
Now only long VARCHAR columns are changed to TEXT on demand (not CHAR)
Internal temporary files can now use fixed length tables if the used VARCHAR columns are short
clause the the SELECT statement used to dump the data
for any table which has a primary or unique key. This
is useful for dumping MyISAM tables which will be later
imported into InnoDB tables.
binlog coordinates corresponding to the dump".
The good news is that now mysqldump can be used to get an online backup of InnoDB *which works for
point-in-time recovery and replication slave creation*. Formerly, mysqldump --master-data --single-transaction
used to call in fact mysqldump --master-data, so the dump was not an online dump (took big lock all time of dump).
The only lock which is now taken in this patch is at the beginning of the dump: mysqldump does:
FLUSH TABLES WITH READ LOCK; START TRANSACTION WITH CONSISTENT SNAPSHOT; SHOW MASTER STATUS; UNLOCK TABLES;
so the lock time is in fact the time FLUSH TABLES WITH READ LOCK takes to return (can be 0 or very long, if
a table is undergoing a huge update).
I have done some more minor changes listed in the paragraph of mysqldump.c.
WL#2237 "WITH CONSISTENT SNAPSHOT clause for START TRANSACTION":
it's a START TRANSACTION which additionally starts a consistent read on all
capable storage engine (i.e. InnoDB). So, can serve as a replacement for
BEGIN; SELECT * FROM some_innodb_table LIMIT 1; which starts a consistent read too.
Revise the --hex-blob help message string. (This will need
revising after merge to 4.1, too, but the CHAR BINARY and
VARCHAR BINARY data types will be BINARY and VARBINRY.)
- 'mysqldump --help' comment that --xeh-blob
doesn't work with --extended-inserts was removed.
It does work now. Thanks to Lachlan
who noticed this wrong help message.
- Switched to use the recently introduced
mysql_hex_string() instead of slow sprintf().
Thanks to Sinisa for the idea.
- 'mysqldump --hex-blob' dumps in HEX not only
BLOBs but also BINARY(x) columns.
Thanks to Paul.
