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Showing entries 1 to 10 of 848 10 Older Entries

Displaying posts with tag: innodb (reset)

Log Buffer #450: A Carnival of the Vanities for DBAs
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This Log Buffer Editions picks few blog posts from Oracle, SQL Server and MySQL.


  • If you grant the DBA role to a user, Oracle also grants it the UNLIMITED TABLESPACE system privilege. If you then revoke the DBA role from this user, Oracle also revokes its UNLIMITED TABLESPACE system privilege.
  • Lost SYSMAN password OEM CC 12gR5.
  • How Terminal Emulation …
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A first look at RDS Aurora
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Recently, I happened to have an onsite engagement and the goal of the engagement was to move a database service to RDS Aurora. Like probably most of you, I knew the service by name but I couldn’t say much about it, so, I Googled, I listened to talks and I read about it. Now that my onsite engagement is over, here’s my first impression of Aurora.

First, let’s describe the service itself. It is part of RDS and, at first glance, very similar to a regular RDS instance. In order to setup an Aurora instance, you go to the RDS console and you …

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Fun with Bugs #39 - Known Bugs in MySQL 5.7.9 GA
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These days everybody is excited with recent announcement of MySQL 5.7.9 GA release. If you are not aware of this event yet (I've noted it from numerous posts even during my short vacation), wait for the Oracle Open World 2015 to begin tomorrow to announce it even wider and louder!

I already have 5.7.9 built from source, up and running, so it's time to check what else we can expect from this new GA release besides new great features (this is a topic for a …

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Using Persistent Memory in RDBMS
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People at Intel started the pmem library project some time ago, it’s open to the broader community at GitHub and  other developers, including Linux kernel devs, are actively involved.

While the library does allow interaction with an SSD using a good-old-filesystem, we know that addressing SSD through SATA or SAS is very inefficient. That said, the type of storage architecture that SSD uses does require significant management for write levelling and verifying so that the device as a whole actually lasts, and your data is kept safe: in theory you could write to an NVRAM chip, and not know when it didn’t …

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Fun with Bugs #38 - Regression Bugs in MySQL 5.6
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I often have to reply to questions related to upgrade from, say, MySQL 5.5.x to latest MySQL (or Percona) Server 5.6.x (5.6.27 for MySQL and 5.6.26 for Percona at the moment). One of them is sometimes about "any known bugs" that may affect a user after upgrade.

One may assume that now, 2 years and 8 months after the first GA release of MySQL 5.6.10, there should be very few bugs (we call them regression bugs) of a kind that is interesting for the user planning upgrade from 5.5.x. I checked yesterday and found out it's not the case actually. It took me half an hour to end up with the list of more than 20 regression bugs that are …

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Fun with Bugs #37 - Bugs fixed in MySQL 5.6.27
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MySQL 5.6.27 was released on September 30 formally. Source code is also available on GitHub, and I have it compiled (some users are less lucky) and running for a couple of days already. In this post I'll comment on some bugs reported by MySQL Community that are fixed there.

I'd like to start with a couple of bugs where patches were also contributed. First of all, the fix suggested by Stewart …

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Create MySQL Index
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Indexes are separate data structures that provide alternate pathways to finding data. They can and do generally speed up the processing of queries and other DML commands, like the INSERT, UPDATE, REPLACE INTO, and DELETE statements. Indexes are also called fast access paths.

In the scope of the InnoDB Database Engine, the MySQL database maintains the integrity of indexes after you create them. The upside of indexes is that they can improve SQL statement performance. The downside is that they impose overhead on every INSERT, UPDATE, REPLACE INTO, and …

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Clarification on “Call me Maybe: MariaDB Galera Cluster”
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Recently Aphyr (Kyle Kingsbury) published

The article is technically valid, I am not going to dispute a conclusion Aphyr made, but it is also quite technically involved, so users who just jump to conclusion may get the wrong impression and we’re left with more questions than ever.

So, let me state what is the real conclusion of this article:
“Galera cluster does not support SNAPSHOT ISOLATION LEVEL, in contract to what was stated in the …

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Unexpected Memory Consumption for Bulk Index Creation in InnoDB (MySQL)
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In my last Hackathon, I worked on MyISAM vs InnoDB for data loading (LOAD DATA IN FILE) and bulk index creation.  My motivation was the following: knowing that some are still using MyISAM for this particular use-case, I wanted to verify/understand if/why InnoDB is slower than MyISAM.  I do not yet have complete results on this specific subject but I found some interesting things that

Advanced Query Tuning in MySQL 5.6 and MySQL 5.7 Webinar: Q&A
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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 (thank you for your great questions).

Q: Here is the explain example:

mysql> explain extended select id, site_id from test_index_id where site_id=1
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: test_index_id
         type: ref …
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Showing entries 1 to 10 of 848 10 Older Entries

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