- #SET PRIMARY KEY VALENTINA STUDIO HOW TO#
- #SET PRIMARY KEY VALENTINA STUDIO CODE#
- #SET PRIMARY KEY VALENTINA STUDIO FREE#
Then (presumably) reexecuting the DELETE will finish the aborted task. Meanwhile, you need to go to each Replica(s) and verify that it is stuck for this reason, then do SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1 In a HA (High Available) system using Replication, this is a minor disaster.
#SET PRIMARY KEY VALENTINA STUDIO HOW TO#
Since Replication is supposed to keep the Master and Replica in sync, and since it has no clue of how to do that, Replication stops and waits for manual intervention. The delete is put into the binlog, but with error 1317. In a single server, simply run the delete again. You probably have no clue of how much was deleted. Some of the rows will be deleted, some won't. In MyISAM, rows are DELETEd as the statement is executed, and there is no provision for ROLLBACK. If it is InnoDB, the query should be rolled back. If you KILL a DELETE (or any? query) on the Master in the middle of its execution, what will be Replicated? That pair of statements guarantees no more than 1000 rows are touched, not the whole table.
#SET PRIMARY KEY VALENTINA STUDIO CODE#
Some of the above code avoids this spurious warning by doing SELECT :=. See Spurious "Statement is not safe to log in statement format." warnings Unfortunately, even with the ORDER BY, MySQL has a deficiency that leads to a bogus warning in mysqld.err. Given that id is the PRIMARY KEY (or UNIQUE), this will be safe: DELETE * FROM tbl ORDER BY date, id LIMIT 111 Moreover, be sure the ORDER BY is deterministic - that is, the fields/expressions in the ORDER BY are unique.Īn example of an ORDER BY that does not quite work: Assume there are multiple rows for each 'date': DELETE * FROM tbl ORDER BY date LIMIT 111 To be safe, add ORDER BY to such statements. This is because the actual order of the records discovered for updating/deleting may be different on the Replica, thereby leading to a different subset being modified. ⚈ FOREIGN KEYs are likely to cause trouble.Īny UPDATE, DELETE, etc with LIMIT that is replicated to Replicas (via Statement Based Replication) may cause inconsistencies between the Master and Replicas. (Changes to Main may not be reflected in New.) ⚈ You must not write to the table during the process. ⚈ You do need enough disk space for both copies. Do this INSERT.SELECT all at once, or with chunking: Optional: ALTER TABLE New ADD PARTITION BY RANGE. This can be done by chunking, or (if practical) all at once: - Optional: SET GLOBAL innodb_file_per_table = ON ⚈ Converting to innodb_file_per_table = ON ⚈ Deleting a large portion of the table more efficiently The following technique can be used for any combination of InnoDB, even with innodb_file_per_table = 1, OPTIMIZE TABLE will give space back to the OS, but you do need enough disk space for two copies of the table during the action. That is rarely worth the effort and time. If you have innodb_file_per_table = 0, the only option is to dump ALL tables, remove ibdata*, restart, and reload. In InnoDB, there is no practical way to reclaim the freed space from ibdata1, other than to reuse the freed blocks eventually. A lot of deleted rows can lead to coalescing of adjacent blocks. An isolated deleted row leaves a block less full. InnoDB is block-structured, organized in a BTree on the PRIMARY KEY. But it may take a long time and lock the table. MyISAM leaves gaps in the table (.MYD file) OPTIMIZE TABLE will reclaim the freed space after a big delete.
#SET PRIMARY KEY VALENTINA STUDIO FREE#
After all, tomorrow's INSERTs will simply reuse the free space in the table. Note: Reclaiming disk space may not be necessary. It may require a COLLATE clause on SET NAMES and/or the in the SELECT.ĭo not use "Row constructors" until you are sure that the Optimizer optimizes them: WHERE (Genus, species) > ($g, $s) Using the INDEX is vital for performance. If, instead of '$g', you use you need to be careful to make sure that has the same CHARACTER SET and COLLATION as Genus, else there could be a charset/collation conversion on the fly that prevents the use of the INDEX. WHERE ts = '$g' AND ( species > '$s' OR Genus > '$g' )Īddenda: The above AND/OR works well in older versions of MySQL this works better in newer versions: WHERE ( Genus = '$g' AND species > '$s' ) OR Genus > '$g' )Ī caution about using strings. If you do not have a primary (or unique) key defined on the table, and you have an INDEX on ts, then consider LOOP In most practical cases, that is unlikely. The drawback is that there could be more than 1000 items with a single id. If = := id FROM tbl WHERE id > ORDER BY id LIMIT 1 WHERE id >= id = ts = ORDER BY id LIMIT 1000,1 How to batch DELETE lots of rows from a large table? Here is an example of purging items older than 30 days: DELETE FROM tbl WHERE ts = ORDER BY id LIMIT 1000,1