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Search Results for: sum

Using pt-table-checksum with Percona XtraDB Cluster

As of Percona Toolkit v2.1.5, pt-table-checksum works correctly with Percona XtraDB Cluster, but it doesn’t work quite like a traditional replication setup because cluster nodes are not like traditional replicas.  In this post I demonstrate …

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Timezone and pt-table-checksum

I recently worked through an issue with a client trying to detect data drift across some servers that were located in different timezones.  Unfortunately, several of the tables had timestamp fields and were set to …

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DBD::mysql 4.014 breaks pt-table-checksum 2.0

DBD::mysql 4.014 breaks pt-table-checksum 2.0.  The cause is unknown, but the effect is a lot of errors like: DBD::mysql::st execute failed: called with 2 bind variables when 6 are needed [for Statement “…” with ParamValues: …

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Checking the subset sum set problem with set processing

Hi, Here is an easy way to run the subset sum check from SQL, which you can then distribute with Shard-Query:

Notice there is no 16 in the list. We did not pass the …

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Modeling MySQL Capacity by Measuring Resource Consumptions

There are many angles you can look at the system to predict in performance, the model baron has published for example is good for measuring scalability of the system as concurrency growths. In many cases …

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PHP Large result sets and summary tables.

We’re working with web site preparing for massive growth. To make sure it handles large data sets as part of the process we work on generation test database of significant size as testing your application …

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INSERT ON DUPLICATE KEY UPDATE and summary counters.

INSERT … ON DUPLICATE KEY UPDATE is very powerful but often forgotten MySQL feature. It was introduced in MySQL 4.1 but I still constantly see people unaware of it. Myself I like this feature big …

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High-load clusters and desynchronized nodes on Percona XtraDB Cluster

There can be a lot of confusion and lack of planning in Percona XtraDB Clusters in regards to nodes becoming desynchronized for various reasons.  This can happen a few ways: An IST or SST joining …

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Percona Toolkit 2.2.15 is now available

Percona is pleased to announce the availability of Percona Toolkit 2.2.15.  Released August 28, 2015. Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or …

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Advanced Query Tuning in MySQL 5.6 and MySQL 5.7 Webinar: Q&A

Thank you for attending my July 22 webinar titled “Advanced Query Tuning in MySQL 5.6 and 5.7” (my slides and a replay available here). As promised here is the list of questions and my answers …

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