1
vote
0answers
37 views

What could cause waiting for table metadata lock?

I am using a MySQL 5.6 DB with MyISAM tables under FreeBSD 8.3. The main part of code is in PHP, but the problem arises, when I launch the self-written on C++ chat-server. I use the mysql.h for DB ...
2
votes
1answer
89 views

Does MySQL guarantee atomic upgrade from read lock to write lock?

If a client session is currently holding a read lock (to allow concurrent reads while already preventing writes), and then acquires a write lock on the same table(s), does MySQL guarantee that the ...
1
vote
2answers
221 views

MySQL views and table locking (5.1 MyISAM)

I have a large (160 million rows, 50GB) table in MySQL 5.1 using MyISAM. If I were to construct a view defined by a fairly complicated query, would a SELECT on the view lock the underlying table?
0
votes
1answer
5k views

What is causing Waiting for table level lock errors?

We got the database hanging twice already and trying to find a cause. show processlist Waiting for global read lock | INSERT INTO {myisam_table} ... In here the disk space was full so we thought ...
1
vote
1answer
160 views

LOAD DATA INFILE on a MyISAM table blocks user read-queries, can we get around this?

I've got a large reference table, 100GB, in a MyISAM table, load it up from scratch goes well (4ish hours) using LOAD DATA INFILE. But we have 1GB each day we want to update in a batch process using ...
3
votes
2answers
311 views

Writing transactions to .MYD file to take Backup

I'm trying to backup MySQL DB by archiving the data directory of required databases. I'm doing FLUSH TABLES WITH READ LOCK before taking the backup, but even then some of the transactions were not ...
4
votes
2answers
16k 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 ...
1
vote
1answer
2k views

MySQL MyISAM Locking question

It was my understanding that MyISAM uses table locking during inserts and updates. To me that meant that read and write by other queries on that table is disallowed until the first insertion or update ...
5
votes
4answers
2k views

Benefits of table level locking

What are the benefits of table level locking which is used by the MyISAM storage engine? Row level locking has lots of benefits like concurrent updates and reads that do not lock the table. Edit Its ...