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Displaying posts with tag: maria10 (reset)

MariaDB storage engines
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This is a list of MariaDB storage engines that are not distributed with MySQL. I think that most of them will work with MySQL, but not all – at least CassandraSE doesn’t.

Engine Description Introduced
XtraDB A fully-compatible fork of InnoDB, mantained by Percona …
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MariaDB 10: Performing fast & inaccurate statistics
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As I already wrote, COUNT(*) can be expensive in InnoDB, because this value is not stored in indexes. Some other storage engines may not store that value. Also, COUNT(), MAX(), MIN() are immediate only if executed on an indexed column. But we don’t want too many indexes, and some exotic storage engines do not support indexes – thus, we may need to execute an aggregate function on a non-indexed column.

Now, the question is: do you really need such values to …

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MariaDB: DELETE … RETURNING
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MariaDB 10.0.5 supports DELETE ... RETURNING, like PostgreSQL. It deletes some rows and returns the specified columns (or, more generally, the specified SELECT expressions) from the deleted rows. As for regular DELETEs, Com_delete is incremented and Com_select is not.

Let’s see what this feature does and what it does not.

You cannot:

  • Cannot use it with INSERT or CREATE TABLE to create a …
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