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Displaying posts with tag: partitions (reset)

MySQL bug 69179 – INFORMATION_SCHEMA.PARTITIONS causes query plan changes
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Shard-Query examines INFORMATION_SCHEMA.PARTITIONS to determine if a table is partitioned.  When a table is partitioned, Shard-Query creates multiple background queries, each limited to a single partition.  Unfortunately, it seems that examining INFORMATION_SCHEMA.PARTITIONS causes query plans to change after the view is accessed.

I have reported bug 69179 to MySQL AB  Oracle Corporation(old habits die hard).

Be careful: If you have automated tools (like schema management GUI tools) then make sure they …

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Dropping MySQL partitions for MariaDB Dynamic column
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In the same time of passionate debat of the best distribution MySQL vs MariaDB on a 120K Euro server(here), i wanted to share the story of drop of InnoDB insert performance for one of our client having a tables between 10 to 100 Billions rows.

In most case this size of table is just a no go in relationnel database.

So why it used to work so far  ?

c1 int, c2 tinyint, c3 mediumint, c4 binary(1), c5 float .
c2 avg cardinality 1000
c3 avg cardinality …







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Dynarr256 for DBACC -or- The death of MAX_ROWS
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Back in 2006 we became aware of problems storing large numbers of rows in a single table in cluster. Johan Andersson and Yves Trudeau have each blogged about the problem and the common workaround here and here.  We've since then done some cleanup to provide a more proper "Table is full" error message when running into this problem.

As explained in the referenced blog posts, the problem is the result of a limitation on the size of the hash index of each …

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Blowing up in memory
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MySQL isn’t too concerned about table handler memory usage – it will allocate row size buffer thrice per each table invocation. There’s a few year old bug discussing UNION memory usage – for each mention in an union one can allocate nearly 200k of unaccounted memory – so a megabyte sized query can consume 7GB of RAM already.

Partitioning though adds even more pain here – it will allocate those three buffers per each partition, so opening a table with 1000 partitions looks like this on memory profile:

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Exchanging partitions with tables
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While I was presenting my partitioning tutorial at the latest MySQL Conference, I announced a new feature that was, as far as I knew, still in the planning stage. Mattias Jonsson, one of the partitions developers, was in attendance, and corrected me, explaining that the feature was actually available in a prototype.


So, we can have a look at this improvement, which I am sure will make DBAs quite happy. The new feature is an …

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Holiday gift - A deep look at MySQL 5.5 partitioning enhancements
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Half a day into my vacation, I managed to finish an article on a topic that has been intriguing me for a while.
Since several colleagues were baffled by the semantics of the new enhancements of MySQL 5.5 partitions, after talking at length with the creator and the author of the manual pages, I produced this article: A deep look at …

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Spider and vertical partition engines with new goodies
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The Spider storage engine should be already known to the community. Its version 2.5 has recently been released, with new features, the most important of which is that you can execute remote SQL statements in the backend servers. The method is quite simple. Together with Spider, you also get an UDF that executes SQL code in a remote server. You send a query with parameters saying how to …
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MySQL Partitions at PHPCon Italia
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I will speak at PHPCon Italia 2009, in Rome, on March 19th.

The subject is a very trendy. I will cover efficiency with partitions, a topic that every DBA and MySQL developers should enjoy.

MySQL Partitions at PHPCon Italia
Employee +0 Vote Up -0Vote Down

I will speak at PHPCon Italia 2009, in Rome, on March 19th.

The subject is a very trendy. I will cover efficiency with partitions, a topic that every DBA and MySQL developers should enjoy.

MySQL Partitions at PHPCon Italia
Employee +0 Vote Up -0Vote Down

I will speak at PHPCon Italia 2009, in Rome, on March 19th.

The subject is a very trendy. I will cover efficiency with partitions, a topic that every DBA and MySQL developers should enjoy.

Showing entries 1 to 10 of 13 3 Older Entries

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