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Displaying posts with tag: memory management (reset)
Automatic Memory Management in RonDB

RonDB has now grown up to the same level of memory management as you find in expensive commercial DBMSs like Oracle, IBM DB2 and Microsoft SQL Server.

Today I made the last development steps in this large project. This project started with a prototype effort by Jonas Oreland already in 2013 after being discussed for a long time before that. After he left for Google the project was taken over by Mauritz Sundell that implemented the first steps for operational records in the transaction manager.

Last year I added the rest of the operational records in NDB. Today I completed the programming of the final step in RonDB. This last step meant moving around 30 more internal data structures towards using the global memory manager. These memory structures are used to represent meta data about tables, fragments, fragment replicas, triggers and global replication objects.

One …

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Making MySQL Better More Quickly

With the upcoming release of MySQL 5.7 I begin to see a problem which I think needs attention at least for 5.8 or whatever comes next. The GA release cycle is too long, being about 2 years and that means 3 years between upgrades in a production environment More people use MySQL and the data … Continue reading Making MySQL Better More Quickly

OPTIMIZE TABLE on Cluster (revisited)

Jonas just wrote a patch to this bug on OPTIMIZE TABLE, and the issue that was also discussed in this blog post. Jonas also fixed this bug when he was at it.

Before, OPTIMIZE TABLE hardly freed up any pages and to defragment you had to do a rolling restart of the data nodes.

Now, there is only a 2% discrepancy between OPTIMIZE TABLE and doing a rolling restart. This is great stuff.
This will fix will make it into 6.3.26 and 7.0.7.

See below for details:

Creating two tables, t5 and t6:

`id` varchar(32) CHARACTER SET utf8 NOT NULL,
`name` varchar(32) …

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Memory (de)allocation,(de)fragmentation, and chkfrag!

(this blog post applies to MySQL Cluster 6.3 and MySQL Cluster 6.4/7.0)

A while ago I discussed Memory Allocation in MySQL Cluster. Here it comes again, but we also discuss fragmentation and a tool to help analyze if there is fragmentation.

The main problem I want to address here is that "I filled up 100% of my DataMemory, then deleted 40% and I cannot create a new table!!". Now this is not such a common problem, but can happen in systems with a lot of insert/deletes (especially on VAR* columns), and can be an issue if you need to create a new table. If the allocation patterns are always on the same set of tables, then this is less of an issue.


  1. If the table is empty and there …
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Showing entries 1 to 4