MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.

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2
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2answers
296 views

MySQL - How much physical space will be reduced by changing the column type?

Lets say I have the following table: CREATE TABLE `my_table` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `relationship_status` varchar(48) CHARACTER SET utf8 COLLATE ...
0
votes
1answer
153 views

How to set unique columns combination

see this table: CREATE TABLE IF NOT EXISTS `default_messages_users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `message_id` int(11) NOT NULL, `owner_user_id` int(11) NOT NULL, `to_user_id` ...
1
vote
1answer
611 views

MySQL INSERTs waiting for UPDATEs (MyISAM)?

In show processlist;, MySQL 5.5, we see that INSERTs tend to wait for UPDATEs to complete before they can proceed. This is on MyISAM tables. We tried INSERT HIGH_PRIORITY and UPDATE LOW_PRIORITY. ...
4
votes
1answer
67 views

Will these queries return the same results?

I have this simple query: SELECT friend_id FROM default_friend WHERE user_id = 1 And the results are below: +-----------+ | friend_id | +-----------+ | 2250 | | 4901 | | ...
6
votes
1answer
3k views

When to switch from MyISAM to InnoDB?

We have a MySQL 5.0 server running all tables as MyISAM. We have two slaves that, in the last month, we have upgraded to MySQL 5.5. Their tables are also still MyISAM. My original plan was to upgrade ...
2
votes
2answers
112 views

How to see what was executed in the database via binlogs for specific date?

I am trying figure out how to "query" binlogs to see what was exectued in the database for a specific date. For example, if I execute mysqlbinlog binlog then the thing just runs forever and it is had ...
2
votes
1answer
145 views

Need some help with this query get all status and their associated comments of me and all my friends

I've several days dealing with this query but can't get it to works as I want. This post is related to this one Several values from different tables in which I tough found the solution but I was ...
1
vote
1answer
115 views

Several values from different tables

I'm totally lost here and not know how to get this to work and hope any can help me here. I have several tables: default_users, default_profiles, default_status, default_comment and latest ...
0
votes
1answer
169 views

Is possible to optimize this query or it's already optimized?

I've three tables: default_users, default_profiles, default_friend. This are the SQL for each one: -- -- Table structure for table `default_users` -- CREATE TABLE IF NOT EXISTS `default_users` ( ...
2
votes
2answers
363 views

Tool to match mysql password encryption

I've created a user ... but forgotten the password mysql> create user 'blayo'@'%' identified by 'right'; Which Linux command line tool can encrypt the password the same way mysql does ? mysql> ...
3
votes
1answer
2k views

Slow insert performance in mysql innodb table for solr indexing

I have a Slave server (MySQL 5.5) having innodb tables. This server is being used for SOLR indexing. Few procedures used to fill 12 million data into 9 tables. The insertion speed is too slow. ...
4
votes
1answer
3k views

Deleting bin logs in replication environment

I have a question about deleting binary logs in the replication environment: We have an environment with 1 master and 2 slaves (running mysql 5.5). Sometimes, we run into a space issues during heavy ...
2
votes
1answer
313 views

Assertion failure from InnoDB while restoring using Innobackupex

I thought I would give back to all those people who help me when I have a problem. This might be something old, but I did not find it anywhere so here goes: We recently upgraded our production DBs ...
1
vote
2answers
629 views

Warnings: Why are statements with limit clause unsafe even if there isn't a limit?

I'm a bit irritated because of some warnings in mysql errorlog. Example 1: [Warning] Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement ...
2
votes
1answer
550 views

Extract some columns data from one table and insert into multiple tables

I have a table with 16,000 records and need to get out some columns and then insert values in multiples tables. For example, suppose I have the following tables tbl_1: id, name, lastname tbl_2: id, ...
6
votes
2answers
2k views

Scaling Percona datacenters: setup and replication

Since our startup has taken off nicely we are now meeting with some of those issues that you always assumed would NEVER effect you. We have already scaled alot of our application stack: we offloaded ...
5
votes
2answers
144 views

DELETE LOW_PRIORITY row visibility

I have a large MyISAM table on MySQL 5.5(Windows XP x64) on which I will have to run DELETE LOW_PRIORITY queries. Does DELETE LOW_PRIORITY make the rows invisible to SELECT statements immediately and ...
2
votes
1answer
381 views

Database Design - Creating Multiple databases to avoid the headache of limit on table size

I need to design database to store information contained in millions of log files generated by devices on trial on network. My first approach was storing all the information in tables contained in a ...
0
votes
1answer
1k views

mysql closing tables taking double the time of process

I have a delete query that is taking a long time. When I check in processlist that status is showing as closing table. It is taking a long time to close tables. ex: I run a query and the total time ...
5
votes
3answers
3k views

Maximum table size for MySQL database server running on Windows (NTFS) Table type InnoDB

I need to design database to store information contained in millions of log files generated by devices on trial on network. I have designed 5 different tables to store log file information. But, as ...
1
vote
2answers
1k views

Need suggestions for best way to archive MySQL (InnoDB) tables

Problem: I have two fairly large tables. A 'wall' table for messages between users with 9 million rows at 2 GB and a 'chapter' table at 2 million rows and 18 GB. I want to keep the number of active ...
4
votes
3answers
6k views

How to change a MySQL previous slave to be a master and remove slave status information?

I have a master -> slave configuration where the master failed. I've been able to reset the old-slave to be a master and the old-master to slave from it. Fine. What I can't seem to do is to remove ...
4
votes
2answers
13k views

way to prevent queries from waiting for table level lock

We've encountered a problem after moving the database of our customer to an extra server. This should have had positive effects on the site's performance, but there is a problem with table locking in ...
3
votes
1answer
58 views

where varcharcol = 0 returns all rows

Suppose I have a table like this: create table mytable(cola int primary key, colb varchar(10)); Let's put some data in it: insert into mytable values(1, 'abc'); insert into mytable values(2, ...
3
votes
1answer
200 views

Get profiles values where message.sender_user_id = profile.user_id

I have this tables: default_messages CREATE TABLE IF NOT EXISTS `default_messages` ( `id` int(11) NOT NULL AUTO_INCREMENT, `subject` varchar(150) COLLATE utf8_unicode_ci NOT NULL, `message` text ...
3
votes
0answers
384 views

Convert Oracle Query for Date to Mysql queries

Need to convert the following oracle queries to MYSQL queries. 1) select to_char(to_date(?,'DD-MM-YY')) from dual; 2) select to_char(next_day(to_date(?,'DD-MM-YY'),'FRIDAY')) from dual; 3) ...
1
vote
1answer
559 views

decreased performance of stored procedure when migrated from mysql server 5.0 to 5.5

i recently testing the move of our db from one server to another. as part of this process i copied all the data to the new db and started testing it. as a comparison i run a store procedure whose ...
1
vote
1answer
111 views

slave issue with load data

When I use "load data infile" on master, the data is properly transferred to slave. But when I use "load data local infile" from remote server to master, the data does not pass on to slave. Why does ...
2
votes
3answers
997 views

MySQL backup with no downtime

I'm running a M/S replication of MySQL 5.5 / innoDB (over ubuntu). My DB is pretty large: ~250GB. I'm looking for a backup tool/service that will do the following: full backup no downtime / locks ...
1
vote
2answers
143 views

Is there a way to get slow-query-log-like profiling information on a single query?

Specifically, I'm looking for this information: # Query_time: 0.011922 Lock_time: 0.000088 Rows_sent: 107 Rows_examined: 663 Rows_affected: 0 Rows_read: 107 # Bytes_sent: 4152 Tmp_tables: 3 ...
3
votes
3answers
932 views

What are the limits on the amount of slaves per master?

I currently have a Master with 2 slaves, all running MySql 5.5. What are the limitations on the amount of slaves I can connect to a single master? what parameters should be taken into affect?
4
votes
1answer
6k views

What can cause TRUNCATE TABLE to take a really long time?

I'm running MySQL5.5 with Master/Slave replication (1 master, 2 slaves). I have a process that runs once a week and truncate a specific table. The table is not large and only has a few thousands ...
10
votes
1answer
2k views

MySQL table with 100,000 records queried often

I have a single database of about 100 tables to store various kinds of information. The most important table is our order table which is used to store customers orders and is over 100000 records as ...
-1
votes
1answer
517 views

What exactly is SOLR? [closed]

It seems like a magical technology that can Do spatial search do full text search The problem is, It doesn't say where does it store all the data. Does it have it's own proprietary database If it ...
0
votes
2answers
901 views

Some queries slower in MySQL 5.5 than 5.0?

We have an exceptionally inefficient process (1.3 million selects, 232k updates) that I'm now recoding to be 1 select and 50 updates. In the meantime, though, today's process ran. We recently updated ...
1
vote
0answers
166 views

How to speed up this query

MySQL doesn't have nearest neighbor search so. So I try to come up with a "distance" that's reasonable so the number of returned query is around 20-200. That way innodb doesn't have to compute ...
1
vote
1answer
503 views

How can I trigger this stored procedure on insert?

I have a table of error messages to which errors will be inserted. I also have a table defining interactions between errors. For example, when a "Power Restored" error occurs, it clears any previous ...
0
votes
1answer
55 views

2 Very similar queries return different number of result (one is null)

I want to find businesses near a point that contain a word that start with sea lat=-6.185068&long=106.773121&keyword=sea&distance=5000&startfrom=0&howmany=20&prominent=5 ...
6
votes
2answers
274 views

Less restrictive query return less result due to simple removing one additional constraint

Look at this query SELECT DISTINCT TB.ID, TB.Latitude, TB.Longitude, 111151.29341326*SQRT(pow(-6.185-TB.Latitude,2)+pow(106.773-TB.Longitude,2)*0.98839228980165) AS Distance FROM ...
-2
votes
1answer
2k views

Why does MATCH (FullTextSearch) AGAINST ('*' IN BOOLEAN MODE) return nothing?

MATCH (FullTextSearch) AGAINST ('k*' IN BOOLEAN MODE) return something Namely anything with a word that start with k MATCH (FullTextSearch) AGAINST ('ku*' IN BOOLEAN MODE) return less MATCH ...
0
votes
1answer
165 views

What database do most mobile start ups use? [closed]

mongodb? MySQL? PostgreSQL? If someone would add pluses and minus, let me know. Why I ask: I am a mobile startup. I need a database that supports spatial indexes. The spatial index must be able to ...
4
votes
1answer
3k views

MySQL transaction size - how big is too big?

I have an import process that runs every so often and I want it to be an 'all or nothing' kind of deal, aka: a transaction. There are many aspects, and the imports may yield anywhere between ...
3
votes
1answer
575 views

Configured MySQL replication but its not working

I have configured MySQL master and slave replication setup on 5.5.x. But for some reason data is not getting replicated properly. What might be the reason? At Master: /etc/my.cnf [mysqld] ...
1
vote
1answer
108 views

How to Archive Only MySQL Master not the Slave.?

Currently I have a Master and Slave. Both of them have same set of data(Can Say are in Sync).The Replication is running fine. What i need to accomplish is that... Need to Archive the Master(Say I ...
2
votes
2answers
4k views

MySQL Error Reading Communication Packets

In MySQL error logs, I see these quite few a warnings like these: 120611 16:12:30 [Warning] Aborted connection 2619503 to db: 'db_name' user: 'user_name' host: 'webapp_hostname' (Got an error reading ...
0
votes
1answer
95 views

Can MySQL be patched

I just saw a note about a security issue in MySQL so thought that I'd better patch my test server just in case. The MySQL site is not very helpful and a quick google revealed lots of people asking how ...
3
votes
2answers
995 views

Can we assign mysql Key_buffer_size value for particular table?

In some documents I found that we can assign key_buffer_size to myisam table. This also includes the following steps: SET GLOBAL myisam_table.key_buffer_size = 4194304; CACHE INDEX test.myisam_table ...
2
votes
2answers
2k views

How to improve MySQL Server Performance..??

As a MySQL DBA most of the times we are supposed to optimize a poorly performing MySQL Servers. Now my question is where to start from like we will need to find out many things as 1.Find the ...
2
votes
1answer
400 views

“set-variable = innodb_thread_concurrency=4” or “innodb_thread_concurrency=4”

Based on this question, the asker wrote: set-variable = innodb_buffer_pool_size=2M set-variable = innodb_additional_mem_pool_size=500K set-variable = innodb_log_buffer_size=500K set-variable = ...
3
votes
1answer
149 views

mysqld-multi with first DB as Slave and second DB as Master

Yesterday, I setup mysqld-multi in my.cnf. It works fantastic, but there is still a further Problem. The first DB on socket 1 running as Slave from a other server. The second one from socket 2 ...