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Displaying posts with tag: data integrity (reset)
How to Restore MySQL Logical Backup at Maximum Speed

The ability to restore MySQL logical backups is a significant part of disaster recovery procedures. It’s a last line of defense.

Even if you lost all data from a production server, physical backups (data files snapshot created with an offline copy or with Percona XtraBackup) could show the same internal database structure corruption as in production data. Backups in a simple plain text format allow you to avoid such corruptions and migrate between database formats (e.g., during a software upgrade and downgrade), or even help with migration from completely different database solution.

Unfortunately, the restore speed for logical backups is usually bad, and for a big database it could require days …

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Complete Megalist: 25 Helpful Tools For Back-End Developers

 

The website or mobile app is the storefront for participating in the modern digital era. It’s your portal for inviting users to come and survey your products and services. Much attention focuses on front-end development; this is where the HMTL5, CSS, and JavaScript are coded to develop the landing page that everyone sees when they visit your site.

 

But the real magic happens on the backend. This is the ecosystem that really powers your website. One writer has articulated this point very nicely as follows:

 

The technology and programming that “power” a site—what your end user doesn’t see but what makes the site run—is called the back end. Consisting of the server, the database, and the server-side applications, it’s the behind-the-scenes functionality—the brain of a site. …

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Disconnecting a replication slave is easier with MySQL 5.5+ (RESET SLAVE vs. RESET SLAVE ALL)

It’s not uncommon to promote a server from slave to master. One of the key things to protect your data integrity is to make sure that the promoted slave is permanently disconnected from its old master. If not, it may get writes from the old master, which can cause all kinds of data corruption. MySQL provides the handy RESET SLAVE command. But as we’ll see, its behavior has changed along with the MySQL versions and it’s easy to shoot yourself in the foot if you use it incorrectly. So how do you safely disconnect a replication slave?

In short

  • For MySQL 5.0 and 5.1, run STOP SLAVE, CHANGE MASTER TO MASTER_HOST='' and then RESET SLAVE.
  • For MySQL 5.5 and 5.6, run STOP SLAVE and then RESET SLAVE ALL.
  • For all versions, ban master-user, master-host and master-password settings in my.cnf, …
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Why does MySQL replication fail?

Read the original article at Why does MySQL replication fail?

When considering active-active multi-master, you must consider it’s foundation technology. Although MySQL replication is straightforward to setup, it can fail in a myriad of ways. Most of those are known and well understood. We can solve them only if we use the technology in the standard way. Click through to the end for multi-master solutions [...]

For more articles like these go to Sean Hull's Scalable Startups

Related posts:

  1. 5 Ways to fortify MySQL replication
  2. Easy …
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Impact of foreign keys absence on replicating slaves

In this post I describe what happens when a slave's Foreign Key setup is different from that of the master. I'm in particular interested in a setup where the slave has a subset of the master's foreign keys, or no foreign keys at all. I wish to observe whether integrity holds.

Making the changes

Which foreign keys do we have and how do we drop them? If you want to do this by hand, well, good luck! Fortunately, common_schema provides with quite a few handy views and routines to assist us. Consider viewing the existing foreign keys on sakila:

master> SELECT create_statement FROM common_schema.sql_foreign_keys WHERE TABLE_SCHEMA='sakila'; …
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Why SQL_MODE is essential even when not perfect

In a recent rant on Why I think SQL_MODE is useless…, I wanted to counteract this statement with why we MUST all use SQL_MODE, even with the inherit flaws.

The fundamental principle of a database is to restore and retrieve data. When I can insert data into the database and then I select this data it is different, this is fundamentally wrong. This is a loss of essential data integrity, something a database should NEVER do.

SQL_MODE solves the problem of “silent truncation” in most instances, and produces an all important error. As pointed out, the SQL_MODE has several limitations, however the benefits do out way the risks. Quality control on source code can reduce the limitations, but no amount of coding can stop the CRUD that comes out of the database without some SQL_MODE settings.

I would ask two more …

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Better MySQL Security and Administration


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With the recent cyber attacks and breaches with data from large organizations including Sony, is your MySQL data safe? What are the best practices for securing and administering your MySQL environment? In this presentation we will cover the essential steps for better MySQL security. We will also cover the different installation and administration tasks necessary to ensure your data is managed.

Presenter: Ronald Bradford
Schedule: Insight Out DB Showcase. October 2011 …

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Statement-based vs Row-based Replication

Replication as most people know it, has mostly been SQL statement propagation from master to slave. This is known as "statement-based" replication. But there is also another kind of replication that is available, "the row-based replication" and that has quite a lot of benefits. In this post I intend on highlighting the advantages and disadvantages of both the types of replication to help you choose the best one. I also follow up with my own recommendation.

MySQL Idiosyncrasies That Bite

The following are my slides that I presented at ODTUG Kaleidoscope 2010. This presentation talks about the MySQL defaults including a non-transactional state, silent data truncations, date management, and transaction isolation options. These are all critical for data integrity and consistency. I also cover in-depth topics including SQL_MODE, character sets and collations.

MySQL Idiosyncrasies That Bite View more presentations from Ronald Bradford.

Apparent vs. actual data integrity

I realized tonight exactly why MySQL’s default behavior of silent truncation bothers me.

It reminds me of people who use a ticketing system and close every ticket as soon as they are done working on the issue instead of actually asking the other party if they are satisfied, because closing more tickets make it look like they’re doing more work.

It reminds me of workers at fast food restaurants who hit the button to make the order disappear as if they have already served me my food, because then their throughput times are faster.

Similarly, with MySQL’s default behavior of silent truncation, it’s as if the database server is saying “the fewer database errors raised, the better.” As in the previous two examples, the metrics do not matter if the quality of service is poor — particularly when the quality of service is poor specifically *because* people are trying to meet the metrics instead of the actual goal …

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