On 7/18/06, Daniel Kinzler daniel@brightbyte.de wrote:
As far as I know, this should not happen if the long running query uses READ UNCOMMITTED (dirty read). Using it should not cause serious problems in our context, save a bit of resources and allow replication to continue while reading from tables. Details on transaction isolation levels can be found here: http://dev.mysql.com/doc/refman/5.0/en/innodb-transaction-isolation.html
DaB. has set the global default isolation level to READ UNCOMMITTED for now. If you are experiencing problems or need data that is guarantied to be consistent under all circumstances, *and* your query does not take long (no more than, say, a minute or so), you can change the isolation level like this:
I already run my queries that can run safely with dirty reads, with dirty reads. Yet DaB has still killed one of my queries, and even accused my query of impacting replag when I wasn't even running one.
The replag paranoia is out of hand...
There is no reason that a select should be blocking other reads no matter what the isolation level is.... Mysql had that sort of behavior with ISAM tables, but it should not exist with innodb..
If this is the case, can we *please* ask mysql to fix their software?