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Displaying posts with tag: sql (reset)

Debugging MariaDB stored procedures with the SQL Error Log
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A very old version of the MySQL site contained a nice header: Speed, Power, Ease of Use. I don’t think that stored programs (routines, triggers, events) were supported, at that time. Now they are, and… developing them is amazingly hard.

There are many problems, for example the language is not flexible and the execution is sloooow. But the biggest problem is that there is no debug API.

In details, one of the biggest problems is that, if you have complex procedures (accessing multiple tables, having error …

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On PostgreSQL. Interview with Bruce Momjian.
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“There are four things that motivate open source development teams:
1. The challenge/puzzle of programming, 2. Need for the software, 3. Personal advancement, 4. Belief in open source”
— Bruce Momjian.

On PostgreSQL and the challenges of motivating and managing open source teams, I have interviewed Bruce Momjian, Senior Database Architect at EnterpriseDB, and Co-founder of the PostgreSQL Global Development Group and Core …


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MySQL Insert from Query
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While working with an error that my students surfaced in the Oracle Database 12c, I blogged about the limit of using a subquery in an Oracle INSERT statement, and I discovered something when retesting it in MySQL. It was a different limitation. I was also surprised when I didn’t find any mention of it through a Google search, but then I may just not have the right keywords.

The original test case uses a subquery to create a multiple row result set for an INSERT statement. Unfortunately, I discovered that you can’t …

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How to execute mysql query from a file in your mysql client terminal?
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Being a terminal fan myself, I usually find myself running queries in the mysql client instead of a UI interface as it is much faster. You get to see the results instantaneously.

One thing which is pretty tedious is editing a big query again after once running it as the whole multi-line formatted query now appears on a single line, thus reducing its readability.

But no problems, you can edit your query from a file and run the file from your mysql client terminal as many times as you want with as many edits.

To do so, follow the below steps:

1. Open your terminal and cd into the …







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1 million SQL Queries Per Second: MySQL 5.7 on POWER8
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I’ve previously covered MySQL 5.6 on POWER (with patch), MySQL 5.6 Performance on POWER8 (spoiler: new performance record) and MySQL 5.7 on POWER.

Of course, The postings on this site are my own and don’t necessarily …

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MariaDB/MySQL: Making ENGINE clause mandatory
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I got this idea from a Valerii Kravchuk’s MySQL bug report:

http://bugs.mysql.com/bug.php?id=71978

In theory, I completely agree that MySQL and forks should not allow us to set a default storage engine which cannot be used to create a table. You can see the same with MariaDB’s SEQUENCE. The MySQL & forks philosophy seems to be: ignore your mistakes, so you can repeat them forever. Which can turn a mistype into a major data loss.

Unless you only use InnoDB and your magic powers tell you that this will never change, …

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MariaDB storage engines
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This is a list of MariaDB storage engines that are not distributed with MySQL. I think that most of them will work with MySQL, but not all – at least CassandraSE doesn’t.

Engine Description Introduced
XtraDB A fully-compatible fork of InnoDB, mantained by Percona …
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Oracle 12c VARCHAR2?
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The Oracle Database 12c documentation says you can set the maximum size of a VARCHAR2 to 32,767 bytes. That’s true except when you’re trying to map a large Java string to a VARCHAR2. It fails when the physical size of the Java string is greater than 4,000 bytes with an ORA-01002 or fetch out of sequence error.

SELECT read_text_file('C:\Data\loader\Hobbit1.txt')
*
ERROR at line 1:
ORA-24345: A Truncation or null fetch error occurred
 
ERROR:
ORA-01002: fetch out of sequence

You need to grant privileges before you can test this code. You can …

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Descending indexes in MariaDB
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Since the dawn of time, MySQL indexes have a limit: they cannot be descending. Yes, ALTER TABLE and CREATE INDEX can contain the ASC and DESC keywords. It is perfectly legal in MySQL. But this does not mean that descending indexes are created. This is a well-known MySQL feature: when it cannot do something, it just pretends to. Well… someone thinks it is a feature. I think it is a bug (a bug is an unexpected behaviour), but what can we do.

The lack of support for descending indexes is only an issue when we need to create an index in which at least one column is ascending and at least one …

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New! MySQL Utilities release-1.4.2-RC
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The MySQL Utilities Team is pleased to announce the latest release candidate (RC) release of MySQL Utilities. This release includes a number of improvements for useabilty, stability, and a few enhancements. A complete list of all improvements can be found in our release_notes.

New Utilities!
We have also included two new utilities.

  • The mysqlrplsync utility was added, which checks data consistency between servers in a replicated setup. 
  • The mysqlrplms utility was added, which provides …




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10 Newer Entries Showing entries 31 to 40 of 1024 10 Older Entries

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