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10 Newer Entries Showing entries 31 to 40 of 143 10 Older Entries

Displaying posts with tag: Technical Blog (reset)

New replication features in MySQL 5.6
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This post was thought of as an attempt to make some performance test with new multi-threaded replication in 5.6, at least that was my initial intention. Based on Luis Soarez – Replication Team Leader in Oracle – post. I wanted to play with new set of variables and features in order to understand how new multi-threaded replication works and make some performance tests.

First impressions:
=================
I will start with my negative impressions about how to setup new replication features:

- Lack of documentation: I know this is a labs release and most of new features are not documented yet, I’ve just found the Luis blog which has some definitions but is mostly an overview than a manual.

- Variables not present: mts% variables are no longer



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Oracle OpenWorld 2011 — Bloggers Meetup
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Isn’t that that time of the year again? Yes, it is — it’s time for our annual Oracle Bloggers Meetup and of course Oracle is piggybacking OpenWorld with the meetup again! ;) What: Oracle Bloggers Meetup 2011 When: Wed, 5-Oct-2011, 5:00pm Where: Main Dining Room, Jillian’s Billiards @ Metreon, 101 Fourth Street, San Francisco, CA [...]
A review of Tungsten Replicator: Part 1 – Installation
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I’ve been following the development of Tungsten Replicator for quiet some time now, and recently was fortunate enough to find the time to take a look at the product in more detail. If you haven’t heard of Tungsten Replicator yet, it’s an open source database replication engine that can be used to complement or completely [...]
Curious case with MySQL replication
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MySQL Replication is a powerful tool and it’s hard to find a production system not using it. On the other hand debugging replication issues can be very hard and time consuming. Especially if your replication setup is not straightforward and you are using filtering of some kind.

Recently we got an alert from our monitoring system that replication stopped on production slave with the following error:

Can't find record in 'some_table', Error_code: 1032;
handler error HA_ERR_KEY_NOT_FOUND;
the event's master log binlog.000011, end_log_pos 735766642

This means that a ROW-based replication event was going to be applied on slave, but could not find the row it was supposed to be applied to. This is something I like about ROW format — it allows you to catch such data synchronization issues right away. In this particular case MIXED format was used, but if



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Alter waiting on Select statement to complete
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A few days ago, we faced an interesting problem on one of our customer’s slave mysqld servers.  An Alter for adding a new column was run on master server took 542 seconds where as it took few hours on the slave server to complete due to a SELECT blocking the Alter was not allowed to complete.

Here is the the select on the master server and it’s execution time from the binary logs.

# at 825737566
#110720 19:55:21 server id 31415  end_log_pos 825737730         Query   thread_id=83250629      exec_time=542   error_code=0
use collect/*!*/;
SET TIMESTAMP=1311216921/*!*/;
/*!\C latin1 *//*!*/;
SET @@session.character_set_client=8,@@session.collation_connection=8,@@session.collation_server=8/*!*/;
ALTER TABLE `track` ADD `source_track_id` int(10) UNSIGNED NULL DEFAULT NULL  AFTER `vendor_track_id`
/*!*/;

Alter statement completed well on the



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Viewing RMAN jobs status and output
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Yesterday I was discussing with a fellow DBA about ways to check the status of existing and/or past RMAN jobs. Good backup scripts usually write their output to some sort of log file so, checking the output is usually a straight-forward task. However, backup jobs can be scheduled in many different ways (crontab, Grid Control, Scheduled Tasks, etc) and finding the log file may be tricky if you don’t know the environment well.
Furthermore, log files may also have already been overwritten by the next backup or simply just deleted. An alternative way of accessing that information, thus, may come handy.

Fortunately, RMAN keeps the backup metadata around for some time and it can be accessed through the database’s V$ views. Obviously, if you need this information because your database just crashed and needs to be restored, the method described here is useless.


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Oracle Exadata “technology that most changed his life” – says Oracle ACE & Pythian DBA Fahd Mirza.
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Pythian’s Oracle ACE, Fahd Mirza appears in this month’s Community: Peer-to-Peer review “In With the New“, as published in the September/October 2011 issue of Oracle Magazine.

Fahd states that “Oracle Exadata Database Machine” has most changed his life – changing the game, and setting very high standards of performance, support, scalability, reliability and unification.

Shout out to Fahd from your peers at Pythian!

I guess there might be just a little truth to Pythian’s growing reputation as an “Oracle ACE Factory” ;), as recently mentioned by Justin Kestelyn in the May 11, 2011 OPN PartnerCast:

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Watch for Pythian speakers at upcoming Oracle Technology Days, NoCOUG, OOUG, SQLSaturday & Pythian Australia.
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It’s a busy summer at Pythian, with our continuing wave of speaking sessions at upcoming community and regional industry events.

Coming to a city near you, watch for Pythian presenting hot Oracle and Microsoft SQL Server database topics:

IN CANADA:

Oracle Technology Days – Montreal
August 9, 2011 – 8:30am – 1pm, Hilton Montreal Bonaventure

Oracle Technology Days – Toronto
August 25, 2011




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Why you should submit a paper for an Oracle User Group event.
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In this post:

  • Introduction
  • Reasons to submit a paper for an Oracle User Group event
  • What should you talk about?

Introduction

Just a few days ago I received a reminder email from Burke Scheld for the “AUSOUG National Conference Series – Perth 2011 – Call for Papers”. I had an event-related conversation with several Oracle guys in my professional networks and the answers I received triggered this blog post. Some of the very good Oracle professionals I personally respect said “…I am not sure what I would get out of it …” or “…I haven’t done anything exciting for the last FEW MONTHS …”.
The answers I received shocked me a bit. Typically I am in the opposite situation where I have so many good things happening I would love to share with the world that I

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How to Run a Streaming Backup with innobackupex
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On many of our clients, we have a need to run XtraBackup as a regular OS user. Aside from running into the issue where tar4ibd was not provided with Percona’s xtrabackup-1.6.2.tar.gz package, our main issues have been with permissions when attempting a streaming backup.

I have found the following:

  • The user needs permissions for a temp directory to stream to/from. The my.cnf of the target database cannot be used because the user does not have permission to write to /tmp/mysql-stdout, so we set a tmpdir in a separate defaults-file.
  • A backup target directory must be used that the user has read/write permissions to. It seems to me a target directory should not be
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    10 Newer Entries Showing entries 31 to 40 of 143 10 Older Entries

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