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10 Newer Entries Showing entries 61 to 70 of 33334 10 Older Entries
#DBHangOps 10/16/14 -- MySQL SYS, Graphs, and more!
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#DBHangOps 10/16/14 -- MySQL SYS, Graphs, and more!

Hello everybody!

Join in #DBHangOps this Thursday, October, 16, 2014 at 11:00am pacific (18:00 GMT), to participate in the discussion about:

  • New in TokuDB 7.5 (rescheduled for next time!)
  • MySQL SYS features and discussion -- what do you want to see in MySQL SYS?
  • What graphs make a good dashboard?

You can check out the event page at on Thursday to participate.

As always, you can still watch the #DBHangOps twitter search, the @DBHangOps twitter feed, or this blog post to get a link for the google hangout on Thursday as well.

See all of you on Thursday!

Page read performance: MySQL 5.7 vs previous releases
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For this test I used sysbench to determine the peak rate for disk reads per second from InnoDB with fast storage. Fast storage in this case is the OS filesystem cache. I want to know the peak for MySQL 5.7.5 and whether there is a regression from 5.6. My summary is:
  • 5.7.5 is 12% to 15% worse than 5.6.21 at 1 thread. I hope we can fix this via bug 74342.
  • 5.7.5 is 2% to 4% worse than 5.6.21 at 8, 16 and 32 threads
  • 5.6/5.7 are much better than 5.0 especially at high concurrency
  • Page size (16k, 8k, 4k) has a big impact on the peak only when compression is used. 

The test server has 40 hyperthread cores and is shared by the sysbench client and mysqld server.

I used my sysbench 0.4

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How To Run Basic Queries of MySQL / MariaDB on Fedora 20 For Newbies !!
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Following Article Describes How To Perform Most Basic MYSQL / MariaDB Queries on Fedora 20? or How to Run MySQL on Fedora 20 ? Which is Latest Version of Linux Based Operating System Project. Last Operation of This Assignment also describes How to change MySQL 'Root' User password on Linux.
It is also a part of 3rd Year, 5th sem Computer Engineering Academic Curriculum of Pune University. As PL 1 Subject. Group A, Assignment 1. It's Problem Statement And Solution is Given Below. You may also Checkout Database Management System complete syllabus & Tutorial of 5th sem subject called Database Management systems application.

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Disabling old_passwords=1
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It is possible to disallow users from using old_passwords=1. This can be done by adding 'maximum-old_passwords=0' to your my.cnf

This prevents users from generating passwords hashes in pre-4.1 format. In MySQL 5.7 old_passwords=1 is already disabled, so this is only useful on 5.6 and earlier.

Be aware that this also restricts old_passwords=2 which is needed for sha256 hashes.

mysql> select @@old_passwords;
| @@old_passwords |
| 0 |
1 row in set (0.00 sec)

mysql> set old_passwords=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show warnings;
| Level | Code | Message |

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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 Narayanan Venkateswaran, which is heading the sharding solution in MySQL Fabric. Together with the conference, we also released MySQL Fabric 1.5.2 as the GA release of MySQL Fabric 1.5 containing

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MariaDB 10.1: Better query optimization for ORDER BY … LIMIT
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For some reason, we’ve been getting a lot of issues with ORDER BY optimization recently. The fixes have passed Elena Stepanova’s scrutiny and I’ve pushed them to MariaDB 10.1. Now, MariaDB’s ORDER BY ... LIMIT optimizer:

  • Doesn’t make stupid choices when several multi-part keys and potential range accesses are present (MDEV-6402)
  • Always uses “range” and (not full “index” scan) when it switches to an index to satisfy ORDER BY … LIMIT (MDEV-6657)
  • Tries hard to be smart and use cost/number of records estimates from other parts of the optimizer (MDEV-6384, MDEV-465, MySQL
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MariaDB 5.5.40 Overview and Highlights
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MariaDB 5.5.40 was recently released (it is the latest MariaDB 5.5), and is available for download here:

This is a maintenance release, and so there are not too many big changes of note, just a number of normal bug fixes. However, there are a few items worth mentioning:

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A discovery - Index Condition Pushdown can cause a slowdown after all
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MariaDB 5.5 and then MySQL 5.6 got Index Condition Pushdown (ICP) optimization (initially coded by yours truly). The idea of ICP is simple: after reading the index record, check the part of WHERE condition that can be computed using index columns, and only then read the table record. That way, we avoid reading table rows that don’t satisfy index condition:

It seems apparent that ICP can never make things slower. The WHERE clause has to be checked anyway, and not reading certain records can only make things faster.

That was what I thought, too, until recently Joffrey Michaie observed the contrary “in the wild”: we’ve got a real-world case where

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Creating PivotTables when importing MySQL data using MySQL for Excel
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In a previous blog post (Importing related MySQL tables into an Excel Data Model using MySQL for Excel) we covered in detail how an Excel Data Model can be created containing tables and their relationships so the data can be analyzed in Excel via a PivotTable. In this blog post we are going to talk about one of the features included since MySQL for Excel 1.3.0 that allows you to create PivotTables for data imported from MySQL tables, views or stored procedures, or more importantly for the whole Excel Data Model if it is created.

Remember you can install the latest GA or maintenance version using the MySQL Installer or optionally you can download directly any GA or non-GA version from the MySQL Developer Zone.

Low-concurrency performance for updates with InnoDB: MySQL 5.7 vs previous releases
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First I tested updates with the Heap engine as a base case and now I report on InnoDB to find regressions that are specific to it. The workload is described in the previous blog post. Response time is measured at 1, 4 and 32 threads for two types of updates. The unindexed update increments an unindexed column. The indexed update updates a column that is in a secondary index. Tests are run with the binlog enabled and disabled. Tests are done for MySQL versions 5.0.85, 5.1.63, 5.5.40, 5.6.21 and 5.7.5. In some cases tests are also done with the adaptive hash index disabled. The test database has 64,000 rows but all updates are to one row (lots of contention). The client is mysqlslap running on the same host as mysqld. The test server has 40 hyperthread  [Read more...]
10 Newer Entries Showing entries 61 to 70 of 33334 10 Older Entries

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