…Innodb tries to limit thread concurrency allowing only innodb_thread_concurrency threads to run inside… one is quite interesting – to avoid too many threads competing to enter innodb queue…many threads are waiting and being active. How many read views are open inside Innodb – this is when transaction…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… multiple threads and multiple concurrent transactions ? HT: The scalability in my …many read-ahead requests can be queued at once. Q13: Is there any IO concurrency control – how many…does Innodb fuzzy checkpointing is activated HT: InnoDB flushes about 128… is that it commits too often and we’re …
Post: When would you use SAN with MySQL ?
March 9, 2009 By 18 Comments
…attached storage and each can do only so many IO requests per second. True the SAN …on commit too. MySQL also has broken group commit (which we have partial fix for) meaning concurrent transaction …people are got used to using SAN based active-passive clusters for availability purposes and they …
Post: Are PHP persistent connections evil ?
November 12, 2006 By 32 Comments
…is there can be only so many connections active between Host “Apache” and Host…too many MySQL server connections. Some people simply do not realize you can increase max_connections variable and get over 100 concurrent… you recycle connection which has uncommitted transactions you run into trouble. If …
Post: MySQL Error Message Nonsenses
March 16, 2008 By 7 Comments
… kind of error complicating automatic handling. When we tested different transactional storage engines we surely saw lock related tables being far… free slot for an undo log. Do you have too InnoDB: many active transactions running concurrently? I hope with pluggable storage engine interface Sun/MySQL…
Post: Estimating Replication Capacity
July 20, 2010 By 4 Comments
… comes the catch in many systems – we find system…OTHER_COMMANDS: 89557 COMMIT_TRANSACTIONS: 90259 ROLLBACK_TRANSACTIONS: 0 DENIED_CONNECTIONS: … same as “concurrency” figure (0.37x) The concurrency as reported…you’re doing this activity anyway. Using this way you…it takes to warmup too (there are …
Post: What to tune in MySQL Server after installation
September 29, 2006 By 118 Comments
…size This one does not really affect performance too much, at least on OS with decent memory…of OK for many workloads with medium write load and shorter transactions. If you have update activity spikes … If application has large jumps in amount of concurrent connections and I see fast growth of …
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
…ask how many disks they have instead of how many systems … Instance without getting in too much trouble with backups etc…issues along you need enough concurrency to utilize multiple hard … and another one for Transactional Logs you will often …want your database box to swap actively – if it does your’…
Post: MySQL extensions for hosting
April 24, 2008 By 11 Comments
…the database. Having many different users …too tight for everyone. And for you it is best to be pro-active…*************************** User: hosting2 Total_connections: 84 Concurrent_connections: 0 Connected_…commands: 85 Commit_transactions: 0 Rollback_transactions: 0 mysql> SHOW TABLE_STATISTICS LIKE…
Post: Which adaptive should we use?
September 15, 2009 By 14 Comments
…many blocks to flush based on… how many modified and unflushed blocks progress speed of the transaction log transaction…method = O_DIRECT innodb_thread_concurrency = 0 innodb_ibuf_active_contract = 1
