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10 Newer Entries Showing entries 91 to 100 of 801 10 Older Entries

Displaying posts with tag: innodb (reset)

Optimizing InnoDB Transactions
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(This is a cross-post from the Engine Yard blog. The original article appears here.)

Here is a question I've actually been asked a few times:

"I am writing a batch processing script which modifies data as part of an ongoing process that is scheduled by cron. I have the ability to group a number of modifications together into a transaction, but I'm not sure what the correct number is?"

First off, I think that this question is interesting not just in the context of batch processing, but it equally applies to all parts of the application. …

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Fun with Bugs #30 - quick review of my reports in February, 2014
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I've got only one comment to my previous post about deadlock, and it was more like a hint based on a different use case, not a real explanation. So far there is nobody who wants to get free beer... Maybe this is even good, as I do not go to the conference and BOF I've submitted will be supervised by my colleague Przemysław Malkowski. But you still have entire month till the conference …

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The MySQL ARCHIVE storage engine – Alternatives
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In my previous post I pointed out that the existing ARCHIVE storage engine in MySQL may not be the one that will satisfy your needs when it comes to effectively storing large and/or old data. But are there any good alternatives? As the primary purpose of this engine is to store rarely accessed data in disk space efficient way, I will focus here on data compression abilities rather then on performance.

The InnoDB engine provides compressed row format, but is it’s efficiency even close to the one from …

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Magic deadlock: what locks are really set by InnoDB?
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Megabytes of text had been written already on InnoDB locking and deadlocks. Still, even very simple cases of deadlocks while working with a table having only one row sometimes make people wonder what happened and why.

Today I want to check if this topic is explained well in the manual and existing blog posts and understood properly. So, it's an exercise for my dear readers and those who like to report bugs as much as I do.

Let's consider a very simple example. In session #1 with default transaction isolation level execute the following:
CREATE TABLE `tt` (
  `id` int(11) NOT NULL,
  …






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Abdel-Mawla Gharieb: Online DDL vs pt-online-schema-change
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One of the most expensive database operations is performing Data Definition Language (DDL, e.g. CREATE, DROP, ALTER, etc.) statements, specially, the ALTER statements because MySQL blocks the entire table for both reads and writes while modifying the table.

For the huge tables, this might take hours to get the table changed which affects the application, so that, a good planning is required for such operations in order to avoid doing these changes during the peak times. For those people who have 24/7 services or limited maintenance window, DDL on huge tables is a really nightmare.

Percona developed a very good tool called …

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Introducing Trite: A tool for automating import of InnoDB tablespaces
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Mysqldump is a fantastic tool for backing up and restoring small and medium sized MySQL tables and databases quickly. However, when databases surge into the multi-terabyte range restoring from logical backups is inefficient. It can take a significant amount of time to insert a hundred million plus rows to a single table, even with very fast I/O. Programs like MySQL Enterprise Backup and Percona XtraBackup allow non-blocking binary copies of your InnoDB tables to be taken while it is online and processing requests. …

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Migration of MTR suites to use InnoDB (continued …)
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This is a continuation of my post on migration-of-mtr-suites-to-use-innodb . To set the context here is a quick recap.

MySQL 5.5 had the following changes with respect to the default engine

  • Default engine in the server changed from MyISAM to InnoDB
  • MTR modified to start server with the old default MyISAM. (This was required because historically most test results were recorded with MyISAM and many of them would fail if tests were run with the new server default,  InnoDB)
  • Tests retained as is in 5.5 and planned …
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Ghosts of MySQL Past: Part 2
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This continues on from my post yesterday and also contains content from my linux.conf.au 2014 talk (view video here).

Way back in May in the year 2000, a feature was added to MySQL that would keep many people employed for many years – replication. In 3.23.15 you could …

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The Effects of Database Heap Storage Choices in MongoDB
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William Zola over at MongoDB gave a great talk called “The (Only) Three Reasons for Slow MongoDB Performance”. It reminded me of an interesting characteristic of updates in MongoDB. Because MongoDB’s main data store is a flat file and secondary indexes store offsets into the flat file (as I explain here), if the location of a document changes, …

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Fun with Bugs #29 - important bug fixes in MySQL 5.6.16
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As you should already know, Oracle had released MySQL 5.6.16 officially on January 31, 2014. You can find all the details in official release notes. In this post I decided to concentrate on important fixes for bugs reported by community in 4 most important categories: InnoDB, replication, partitioning and optimizer.

Let's start with Bug #70768, "Persistent optimizer statistics often causes LOCK_open stalls". It's well known that persistent statistics for InnoDB …

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10 Newer Entries Showing entries 91 to 100 of 801 10 Older Entries

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