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10 Newer Entries Showing entries 61 to 70 of 963 10 Older Entries

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MySQL and swapping
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Did you ever encounter swap space issue with MySQL ? This problem is really annoying and here are some possible solutions :

1) Track memory usage.. Try to identify the bottleneck using query below. It is not trivial job to zero in on the problem heap.. There are several temp tables being created at run time. Also estimating the OS cache being used by system MYISAM tables is not easy

SELECT ( @@key_buffer_size + @@query_cache_size + @@innodb_buffer_pool_size + @@innodb_additional_mem_pool_size + @@innodb_log_buffer_size + 80 * ( @@read_buffer_size + @@read_rnd_buffer_size + @@sort_buffer_size + @@join_buffer_size + @@binlog_cache_size + @@thread_stack + …

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On Hadoop RDBMS. Interview with Monte Zweben.
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“HBase and Hadoop are the only technologies proven to scale to dozens of petabytes on commodity servers, currently being used by companies such as Facebook, Twitter, Adobe and”–Monte Zweben.

Is it possible to turn Hadoop into a RDBMS? On this topic, I have interviewed Monte Zweben, Co-Founder and Chief Executive Officer of Splice Machine.


Q1. What are the main challenges of applications and operational analytics that support real-time, interactive queries on data updated in real-time for Big Data?

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XFS and EXT4 Testing Redux
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In my concluded testing post, I declared EXT4 my winner vs XFS for my scenario. My coworker, @keyurdg, was unwilling to let XFS lose out and made a few observations:

  • XFS wasn’t *really* being formatted optimally for the RAID stripe size
  • XFS wasn’t being mounted with the …
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MySQL: The most popular open source database for WWW
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(Note : This an Article from last year when MySQL5.6 was released)

While Database technology is one of the oldest branches of computer science, it remains a fundamental computer technology that continues to attract new research. The current focus of Databases technology is towards adapting hot new tends like multi-core chips, solid state devices, NOSQL and Cloud. So what does a contemporary internet developer look for in a database for the internet era? And why does MySQL remain the most popular database for the web?


For a database to be useful while developing products for the …

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MySQL 5.7.5- More variables in replication performance_schema tables
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At MySQL, replication usability is of utmost importance to us. Replication information has long been part of SHOW commands, SHOW SLAVE STATUS occupying a major chunk of it. The other sources of replication information being:


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MySQL 5.7.5-labs: Multi-source Replication
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Multi-source replication for MySQL has been released as a part of 5.7.5-labs-preview
downloadable from It is one among the several features that are
cooking in the replication technologies at MySQL.  (For a birds eye view of all
replication features introduced in 5.7 and labs, look  at the blog posts here and …

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Slow query log – Confusing information in manuals
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Below is the excerpt from MySQL manuals on slow query log :

“By default, administrative statements are not logged, nor are queries that do not use indexes for lookups. This behavior can be changed using log_slow_admin_statements and log_queries_not_using_indexes, as described later. “

This manual entry is kind of misleading . It means that queries not using indexes are not logged by default. Let us see what the reality is :

1) Let us see if queries not using indexes are being logged.

Below table does not have index:

mysql> describe employee ; …
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High-Availability at MySQL Central
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This year’s MySQL Central at Oracle Open World was an exhilarating experience. In contrast to the previous year’s MySQL Connect events, MySQL have now got their own Central at the main Oracle Open World. In the previous years, we were always short on time and trying to get a lot of sessions into just two days was just to much. This time I could both present sessions, attend sessions by other users, and also to talk to people in the MySQL community: something that I really enjoy and also find very valuable to see where we should be heading.

This year, the “MySQL Fabric Team” representation on MySQL Central was me and …

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IO, IO, It’s Off to Testing We Go
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In my last post, I learned in disappointing fashion that sometimes you need to start small and work your way up, rather than trying to put together a finished product. This go-round, I’ll talk about my investigation into disk IO.

In an effort to better understand the hardware I have and it’s capacities, I started off by just trying to get some basic info about the RAID controller and the disks. This hardware in particular is a Supermicro, with a yet unknown RAID controller and 16 4TB disks arranged in RAID 6. Finding out more …

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Even If You Fail, You Can Still Learn
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As many learning experiences do, this one also starts out “So I was working on a project at work and…”.  In this case, the end result is to try to run as many concurrent copies of MySQL on a single server as possible, maintaining real time replication each running differing data sets. To help with this, I sent out to do this on a server with 36 7200rpm 4GB SATA disks, giving me roughly 120TB of available space to work with.

This isn’t an abnormal type of machine for us. Sometimes you simply need a ton of disk space. There is a quirk with this particular machine that I’ve been told: the RAID controller has some …

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10 Newer Entries Showing entries 61 to 70 of 963 10 Older Entries

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