MariaDB is an open source RDBMS that is designed to be a "drop-in" replacement for MySQL.

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3
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1answer
142 views

Should I use utf8_unicode_ci or utf8_slovak_ci?

I was using utf8_slovak_ci collation until now, but I read that utf8_unicode_ci sorts very wide range of languages. Does it mean, I do not need to use separate collation for every language and I can ...
3
votes
2answers
244 views

Best Indexing Strategy for Query with Equality[A], Range[B], Group By[C], AND Order By[count(P)]

I have a poorly performing query: SELECT user_id, count(item_id) as count FROM table items WHERE category = 'magazine' AND created_at > 1384754400 GROUP BY user_id ORDER BY count(item_id) desc ...
3
votes
3answers
844 views

How can I improve my table design for different types of an entity?

Consider an accounting system as an example. I have an Entity called Client. Client can be of different types, with different fields applicable to different types. I consider creating separate tables ...
3
votes
1answer
46 views

Performance schema: 'stage/sql/Sending data'

Background I am using MariaDB 10.0 but MySQL 5.6 answers are also of interest. Two machines cloned from the same image, same MariaDB configuration as far as I could tell, same dataset. One machine ...
3
votes
0answers
449 views

WSREP: failed to report last committed and stop

I have galera cluster and I have 4 nodes. I'm importing some data. however one node gives error. Warning. The warning is; warning WSREP: Failed to report last committed 59102, -q (interrupted system ...
3
votes
0answers
647 views

Which is the right way to fix “Error: 1205 Lock wait timeout exceeded; try restarting transaction”

I have a PHP script that sync a local DB against external datasource. Each time the script runs I perform some triggers on the DB where INSERT or UPDATE happen. These are the the triggers for that ...
2
votes
3answers
608 views

mariadb ignoring force index

I'm trying to tune a relatively simple query: select bt.col1,bt.col2 from bigtable bt join smalltable st on bt.smalltable_id = st.smalltable_id where st.name = 'some name occuring only once in st' ...
2
votes
1answer
45 views

Keywords and reserved words: What's a poor boy to do?

We have been using MySQL since its beginnings. Back then we thought that descriptive column names were a good idea. So we created columns like date, open, high, low, close, volume, signal and so on ...
2
votes
1answer
317 views

Does PostgreSQL support multi-threaded replication?

Is PostgreSQL replication single-threaded ? Are there any tools to achieve multi-threaded replication ? I'm asking this since Mariadb support this and currently I'm learning both these dbs.
2
votes
2answers
574 views

Slow query responce on different mysql versions, percona, MariaDB

LEFT JOIN is supposed to be faster than a NOT IN query. This is what I've read online. But practically, this seems to be opposite. I have the following query here, INSERT IGNORE INTO callrequests (...
2
votes
1answer
904 views

UTF8 vs ASCII or custom binary format: high-performance optimization on very big tables

The summary of my question is whether there are advantages, even if minimal, to use ASCII, or even a smaller format designed yet created specifically for the situation, instead of UTF-8 for strings. ...
2
votes
2answers
55 views

Galera: any drawback of enabling wsrep_log_conflicts and cert.log_conflicts?

We have a HAProxy which balances reads and writes to only one (of three) Galera nodes. If this balancing works fine, the parameters wsrep_log_conflicts and cert.log_conflicts should never log any ...
2
votes
2answers
127 views

Master/Slave desyncronisation

Some manual operations (writes) have been made on SLAVE instead of MASTER resulting in the replication being stopped. Could not execute Delete_rows_v1 event on table xxx.newsletter; Can't find ...
2
votes
2answers
2k views

InnoDB + TokuDB fills up RAM then start swapping

I'm trying to face difficulties with my database lately. I've migrated from MyISAM to TokuDB v7.0.4 and InnoDB. I'm using MariaDB - 5.5.34-MariaDB-1~wheezy-log. My problem is that MariaDB fills up RAM ...
2
votes
2answers
49 views

Improve query “JOIN … WHERE NOT EXISTS (SELECT 1 FROM … WHERE … )”

I'm trying to optimize a query because the plan generates a full table scan for a subquery. Data The (simplified) table structure: CREATE TABLE RECORD ( ID INTEGER PRIMARY KEY AUTO_INCREMENT ); ...
2
votes
1answer
76 views

Hybrid Synchronous / Asynchronous Replication?

We have a situation where we would like to have synchronous replication in our main data center, but replicate asynchronously to another region. Our second data center is 3,000 miles away (Site B) and ...
2
votes
1answer
240 views

Corrupt InnoDB: Start mysqld only innodb_force_recovery=6

I am working with version 10.0.19-MariaDB-1~trusty-log and I'm only able to restart mysqld with innodb_force_recovery=6 and I don't know why. The output of the /usr/sbin/mysqld is the following: ...
2
votes
2answers
201 views

ORDER BY indexedColumn ridiculously slow when used with LIMIT on MySQL

The MyISAM table has 4.5m rows. Query with just LIMIT returns fast; query with just ORDER BY returns fast; combining both it never finishes. I've also tried USE INDEX(indexedColumn, Latitude, ...
2
votes
1answer
175 views

Is a “Ranking” query's ORDER BY in FROM subquery is preserved?

I've read in the following links that the ORDER BY in FROM subquery can be ignored. Quoted from MariaDB knowledge base A query such as SELECT field1, field2 FROM (SELECT field1, field2 FROM table1 ...
2
votes
2answers
394 views

Slow “CREATE TABLE” and “TRUNCATE” on MySQL / MariaDB

I am fighting with performance issues on a local MariaDB instance. Fun thing: I previously had problems with all my INSERT and UPDATE and DELETE queries. This got signigicantly faster (~40ms -> less ...
2
votes
3answers
4k views

Could not start mysql or MariaDB. Permissions were ok, but mysql-bin.index permission error

Using MariaDB 5.5.36. Here's what I got while trying to start MariaDB: # syslog Dec 14 09:40:52 vps1497 mysqld_safe: Starting mysqld daemon with databases from /var/lib/mysql Dec 14 09:40:52 vps1497 ...
2
votes
1answer
187 views

How can I solve this error InnoDB: is in the future?

InnoDB: is in the future! Current system log sequence number 412018685584. InnoDB: Your database may be corrupt or you may have copied the InnoDB InnoDB: tablespace but not the InnoDB log files. See ...
2
votes
2answers
4k views

Memcached plugin on MariaDB?

I'd like to try new NoSQL feature in MySQL 5.6 but I am using MariaDB 10.0.2 on Debian 6 and don't fancy coming back to MySQL. I'm wondering whether the memcached plugin has been added to MariaDB? ...
2
votes
2answers
102 views

MariaDB 10.1.16 on Ubuntu fails to start: WSREP Failed to recover position

I'm using 10.1.16-MariaDB-1~xenial from the official MariaDB apt repository for 10.1 [stable], via the University of Texas mirror. I had a perfectly functioning MariaDB Galera cluster setup on 3 ...
2
votes
1answer
230 views

The right way of starting up a Galera Cluster

I am confused about the bootstrap process of MariaDB Galera Cluster. Let's say we have 3 nodes of a MariaDB Galera Cluster, working and functioning normally on CentOS6/7. However, at some point we ...
2
votes
1answer
441 views

grastate.dat with seqno -1 on a healthy cluster. Why?

We use those versions: # rpm -qa | egrep '(galera|maria)' mariadb-libs-5.5.41-2.el7_0.x86_64 mariadb-galera-common-5.5.40-6.el7ost.x86_64 mariadb-galera-server-5.5.40-6.el7ost.x86_64 mariadb-5.5.41-2....
2
votes
1answer
166 views

3 minutes to import 327Mo database

We do database import a lot of times per day on a server with those specs : Xeon E5-1620v2 4c/8t @ 3,8Ghz 32 Go DDR3 ECC 1600MHz Hard Drive 2x 3 To SATA3 MariaDB 10.14 with XtraDB Given a 327Mb ...
2
votes
1answer
131 views

Making MySQL use primary index without hinting or forcing

I have the following db structure: CREATE TABLE `question` ( `id` int(11) NOT NULL AUTO_INCREMENT, `level_id` int(11) NOT NULL, `video_id` int(11) NOT NULL, `is_active` tinyint(1) NOT NULL, ...
2
votes
1answer
2k views

MariaDB, Triggers and last_insert_id

I have a situation where I have three tables: sample, sample_name and run (extra columns removed to be only relevant information). CREATE TABLE `sample` ( `sample_id` int unsigned NOT NULL ...
2
votes
1answer
3k views

MariaDB and XtraDB/InnoDB plugins

In my vps, I thought of switching from MySQL to MariaDB (using Monty's repository for Debian Squeeze). Copying over my.cnf from MySQL to MariaDB, I saw that the new config file (the one from the ...
2
votes
2answers
2k views

Is there any performance difference among MariaDB (xtradb plugin) and XtraDB Server for InnoDB?

Title says it all. However i have to enter at least 30 characters.
2
votes
1answer
4k views

MariaDB XtraDB Performance Tuning

I believe that innodb has a single read thread. However, with MariaDB you can set multiple read threads. I'm unsure what the recommended value would be. Questions Does anyone have any experience ...
2
votes
3answers
78 views

2 fast SQL queries get slow when bunched as subquery on a very large table

I'm trying to use a subquery to speed up a query on a very large table right now 30 million row it most likely going to end up close to 1 billion rows. My table lnmntr is as follow Lnmntr_ndx: ...
2
votes
1answer
267 views

ERROR WSREP`: gcs/src/gcs.cpp:gcs_open():1379:` Failed to open channel 'test_cluster'

I have three server that I want to Install Galera clustering on them, I followed this link to install and config it. but when I want to start the first server I got this error : root@node107:/home/...
2
votes
1answer
103 views

MariaDB subquery cache scope and settings

I am migrating an application from MySQL 5.6 to MariaDB 10. One major new feature of MariaDB is the subquery cache. I am trying to determine the expected effect this cache will have on our ...
2
votes
1answer
295 views

Two updates cause a deadlock

I have a mysql queue with the following sheme: CREATE TABLE IF NOT EXISTS `media` ( `mid` int(11) NOT NULL AUTO_INCREMENT, `order_type` int(11) NOT NULL, `media_id` varchar(50) COLLATE ...
2
votes
1answer
101 views

SQLyog and MariaDB engine

I am quite new in MariaDB and I use SQLyog Community Edition as the frontend GUI. Whenever I create a new table, on the Engine dropdown, there is no XtraDB option. Is there any additional steps I am ...
2
votes
1answer
9k views

The user specified as a definer ('root'@'%') does not exist

I have a trigger defined as follow: USE `veeva_bi`; DELIMITER $$ DROP TRIGGER IF EXISTS veeva_bi.account_ai$$ USE `veeva_bi`$$ CREATE DEFINER = CURRENT_USER TRIGGER `veeva_bi`.`account_ai` AFTER ...
2
votes
1answer
388 views

MariaDB 10 InnoDB Partition with Data Directory

mysql --version mysql Ver 15.1 Distrib 10.0.20-MariaDB, for Linux (x86_64) using readline 5.1 I have a MariaDB 10 installed, though I tried with the 5.5 release in the CentOS repos. I'm ...
2
votes
2answers
138 views

INET6_ATON returns NULL for input parameter

I'm making a MySQL Stored Procedure which takes a string representation of an IPv4 or v6 address and converts it to binary using INET6_ATON. I know that my version of MySQL supports this function ...
2
votes
1answer
77 views

How should a numeric value that is an external key be stored?

This is something I was pondering recently. trying to determine how to store certain values. The best wide spread example I can think of is Federal Employee Identification Number - more commonly knows ...
2
votes
1answer
4k views

what is the right way to restart a mariadb galera cluster?

I am trying to restart cluster. I have two problems in stopping cluster and starting cluster In stopping cluster, I follow the instruction https://software.mirantis.com/reference-documentation-on-...
2
votes
1answer
434 views

Threads_cached 0 while thread_cache_size > 0

I'm trying to little bit understand with some MySQL (in my case - MariaDB) performance. One point I found - "threads caching". So - I set: thread_cache_size = 4 in my.cnf and restart server. In ...
2
votes
1answer
736 views

How to force MySQL/MariaDB to show numbers in scientific notation?

I have a local MariaDB server 5.5.37 where I have some numeric data in it stored as DOUBLE. I need to perform some queries on this data (things like AVG(...) or STD(...)), and I also have a MySQL ...
2
votes
2answers
94 views

I need help optimizing a not that complicated query that returns unexpedcted performance problems

I have a table that stores details about incoming and outgoing phone calls such as when a call was made, or when a call was received, the phone number of the caller, and the phone number of the ...
2
votes
1answer
971 views

MySQL (or MariaDB) multi-master without MMM

I've been reading blogs on MySQL multi-master setup. The way I've used MySQL replication in the past was master-slave where if the master died (or was being taken down for maintenance) we would shut ...
2
votes
1answer
426 views

MariaDB 5.5 vs MySQL 5.7 query optimizers

I have a query that optimizes differently in MariaDB 5.5.37 and MySQL 5.0 and MySQL 5.7. When poorly optimized it takes about 400 seconds to run, but on MySQL 5.7 which optimizes it differently, it ...
2
votes
1answer
640 views

MariaDB Cluster - data consistency for updates and auto_increment

I have two different MariaDB servers and plan to merge data into one database and create MariaDB Cluster with 3 nodes. I read about Galera and multi-master replication - which MariaDB Cluster use and ...
2
votes
1answer
690 views

MariaDB: Created_tmp_disk_tables high after start

today i looked in the status of my MySQL server which is based on MariaDB and i noticed that Created_tmp_disk_tables is very high (over 168k). I think this is the reason for my high I/O usage. I try ...
2
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0answers
57 views

Open source & cheap 'data at rest' encryption solutions

So I am exploring some options about database encryption. The best options are commercial (TDE). I am looking for an open-source implementation. Recent releases of MySQL and MariaDB have data-at-rest ...