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Pseudo GTID, Row Based Replication
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This post continues Pseudo GTID, in a series of posts describing an alternative to using MySQL GTIDs.

The solution offered in the last post does not work too well for row based replication. The binary log entries for the INSERT statement look like this:

# at 1020
# at 1074
#141020 12:36:21 server id 1  end_log_pos 1074  Table_map: `test`.`pseudo_gtid` mapped to number 33
#141020 12:36:21 server id 1  end_log_pos 1196  Update_rows: table id 33 flags: STMT_END_F

BINLOG '
lddEVBMBAAAANgAAADIEAAAAACEAAAAAAAEABHRlc3QAC3BzZXVkb19ndGlkAAMDBw8CQAAE
lddEVBgBAAAAegAAAKwEAAAAACEAAAAAAAEAA///+AEAAACL10RUJDg2ZmRhMDk1LTU4M2MtMTFl
NC05NzYyLTNjOTcwZWEzMWVhOPgBAAAAlddEVCQ4Y2YzOWMyYy01ODNjLTExZTQtOTc2Mi0zYzk3
MGVhMzFlYTg=
'/*!*/;

Where's our unique value? Encoded within

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MySQL sys version 1.2.0 released
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MySQL sys version 1.2.0 has just been released.

All views now work with MySQL 5.7.5, and the ONLY_FULL_GROUP_BY changes.

There is also a new script available (generate_sql_file.sh) that will allow RDS users to easily generate a single SQL file, using a specified user, that can be loaded in to an RDS instance. See the README for details on how to use that.

Here’s a full summary of the other changes:

Backwards Incompatible Changes

  • The host_summary_by_stages and user_summary_by_stages wait_sum and wait_avg
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libAttchSQL Hits First GA!
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We have come a long way since the first code was put down for libAttachSQL on the 4th July. It has been a fantastic project to work on so I am very pleased to announce our first GA release.

For those who haven't seen it so far libAttachSQL is a non-blocking, lightweight C API for MySQL servers. It is Apache 2.0 licensed so is compatible with most Open Source and commercial licensing. HP's Advanced Technology Group saw a need in this field not just for HP itself but for other companies and projects too.

As for the GA release itself, there are not many changes over the RC release beyond stability fixes. A full list can be seen in the version history documentation.

In addition to the GA release we have recently had a driver for

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Pseudo GTID
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Pseudo GTID is a method to implement a GTID-like solution where slaves are easily connected to one another. This blog post and the following ones will describe work in progress (some 80% completed), where simulation of GTID makes for a good enough basis for refactoring replication topologies. I'm coding this in orchestrator, which already provides a substantial infrastructure support for this.

The final goal: orchestrator will allow you to move a slave below another, using only the data available by those two slaves. The usage is obvious:

  • Easy master failover (master dead? Orchestrator will choose the most advanced slave to promote and make it master of its siblings)
  • Slave promotion in complex topologies (with
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Percona XtraDB Cluster: How to run a 2-node cluster on a single server
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I reckon there’s little sense in running 2 or more Percona XtraDB Cluster (PXC) nodes in a single physical server other than for educational and testing purposes – but doing so is still useful in those cases. The most popular way of achieving this seems to be with server virtualization, such as making use of Vagrant boxes. But in the same way you can have multiple instances of MySQL running in parallel on the OS level in the form of concurrent mysqld processes, so too can you have multiple Percona XtraDB Cluster nodes. And the way to achieve this is precisely the same: using dedicated datadirs and different ports for each node.

 

Which ports?

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Improvements to the MySQL `IGNORE` Implementation
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In 5.7.5, as a part of the larger effort to improve error handling, we re-implemented the IGNORE clause (WL#6614). The IGNORE clause is a MySQL extension to the SQL standard. It affects the errors which occur for each row. The new implementation aims to make the behavior of the IGNORE clause more consistent.

Statements which support the IGNORE clause are:

  • INSERT [ IGNORE ]
  • UPDATE [ IGNORE ]
  • DELETE [ IGNORE ]
  • LOAD DATA [ IGNORE ]
  • LOAD XML [ IGNORE ]
  • CREATE TABLE… [ IGNORE ] SELECT

When the INSERT statement is used to insert a number of rows into a table, an exception during processing would normally abort the statement and return an error message. With the IGNORE keyword, rows that cause certain exceptions are ignored,

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XFS and EXT4 Testing Redux
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In my concluded testing post, I declared EXT4 my winner vs XFS for my scenario. My coworker, @keyurdg, was unwilling to let XFS lose out and made a few observations:

  • XFS wasn’t *really* being formatted optimally for the RAID stripe size
  • XFS wasn’t being mounted with the inode64 option which means that all of the inodes are kept in the first 2TB. (Side note: inode64 option is default in newer kernels but not on CentOS 6’s 2.6.32)
  • Single threaded testing isn’t entirely accurate
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Making UUID() and RAND() replication safe
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MySQL's UUID() and RAND() functions both provide with (pseudo) indeterministic result. UUID()'s result is moreover bound to the host on which it executes. For this reason, both are unsafe to replicate with STATEMENT binlog format. As an example, consider:

master> create table test.uuid_test (id int, u varchar(64));

master> insert into test.uuid_test values (1, UUID());
Query OK, 1 row affected, 1 warning (0.03 sec)

master> select * from test.uuid_test;
+------+--------------------------------------+
| id   |
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MariaDB 10.1 Brings Compound Statements
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A very old post of mine in 2009, MySQL’s stored procedure language could be so much more Useful suggested that it would be nice if MySQL could be adapted to use compound statements directly from the command line in a similar way to the language used for stored procedures. I’ve just seen that this seems to be possible now in MariaDB 10.1. See the release notes.

I now need to look at this. So thanks, it looks like this feature request is now available.

[ERROR] COLLATION ‘utf8_general_ci’ is not valid for CHARACTER SET ‘latin1′
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Recently come across the problem where mysql server stop running and refusing to start with an error

The server quit without updating PID file (/var/run/mysqld/mysqld.pid)

Checked Mysql error log and found that an invalid usage of charset with collation causing problem.

error log:
141017 12:20:41 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
while 15088 [ERROR] COLLATION 'utf8_general_ci' is not valid for CHARACTER SET 'latin1'
15088 [ERROR] Aborting

In this case mysqld trying to start  with  character-set-server = latin1 and collation-server = utf8_general_ci, which is not valid.
The following is the right charset value for COLLATION ‘utf8_general_ci’

node1 [localhost] {msandbox} ((none))





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Showing entries 1 to 10 of 16443 10 Older Entries

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