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Search Results for: innodb thread concurrency

thread_concurrency doesn’t do what you expect

Over the last months I’ve seen lots of customers trying to tune the thread concurrency inside MySQL with the variable thread_concurrency. Our advice is: stop wasting your time, it does nothing on GNU/Linux Some of …

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InnoDB’s gap locks

One of the most important features of InnoDB is the row level locking. This feature provides better concurrency under heavy write load but needs additional precautions to avoid phantom reads and to get a consistent …

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How Innodb Contention may manifest itself

Even though multiple fixes have been implemented in Percona Server and MySQL 5.5, there are still workloads in which case mutex (or rw-lock) contention is a performance limiting factor, helped by ever growing number of …

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Effect from innodb log block size 4096 bytes

In my post MySQL 5.5.8 and Percona Server: being adaptive I mentioned that I used innodb-log-block-size=4096 in Percona Server to get better throughput, but later Dimitri in his article MySQL Performance: Analyzing Percona’s TPCC-like Workload …

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Tuning InnoDB Concurrency Tickets

InnoDB has an oft-unused parameter innodb_concurrency_tickets that seems widely misunderstood. From the docs: “The number of threads that can enter InnoDB concurrently is determined by the innodb_thread_concurrency variable. A thread is placed in a queue …

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Fix of InnoDB/XtraDB scalability of rollback segment

Recently I wrote about InnoDB scalability on 24-core box, and we made research of scalability problems in sysbench write workload (benchmark emulates intensive insert/delete queries). By our results the problem is in concurrency on rollback …

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XtraDB/InnoDB CPU bound benchmarks on 24cores server

One of our customers gave me a chance to run some benchmarks on 24-core (intel cpu based) server, and I could not miss it and ran few CPU-bound tasks there. The goal of benchmarks was …

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MySQL 5.0, 5.1 and Innodb Plugin CPU Efficiency

We’ve recently done benchmarks comparing different MySQL versions in terms of their CPU efficiently in TPC-C like Workload. We did it couple of weeks ago so MySQL 5.0.67, MySQL 5.1.29 and Innodb Plugin 1.0.1 were …

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Heikki Tuuri answers to Innodb questions, Part II

I now got answers to the second portions of the questions you asked Heikki. If you have not seen the first part it can be found here. Same as during last time I will provide …

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Innodb Performance Optimization Basics

Note: There is an updated post on this topic here. Interviewing people for our Job Openings I like to ask them a basic question – if you have a server with 16GB of RAM which …

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