… which can become really inefficient. It is especially inefficient with Innodb tables both in terms of space (some tables would keep…, but require at least 16K page in Innodb), keeping all tables open in Innodb dictionary and number of other challenges in IO…_id,id, title,body columns and create post123 as view: create view post123 as select id,title,body from post where user…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…, simply ignore this column. It is used to prevent wide innodb primary keys on the MV. mysql> select mview$pk as… demonstration purposes, I did the following: Created one view of each type. The view is the same as the one specified above… The first parameter to flexviews.refresh() is the materialized view id. Each view has an identifier which can be obtained with flexviews…
Post: InnoDB thread concurrency
June 5, 2006 By 4 Comments
…) and storage engine. From storage engine’s point of view it works how (very simplified): mysql calls storage engine…_innodb–; ENTER; } retry: if (entered_thread < innodb_thread_concurrency) { entered_threads++; thread->n_tickets_to_enter_innodb = innodb_concurrency_tickets; ENTER; } if (innodb…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
… Sending data select count(*) from sbtest,sbtest x Trx read view will not see trx with id >= 12304, sees < 12301 As... unlocking it straight after. Not so for Innodb. Unless table is being locked explicitly Innodb “converts” table lock to “no lock” hence…. You almost never will run into problems with Innodb table level locks because innodb will only set intentional level locks for everything…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… better. Q28: My impression (from an external user of Innodb point of view) is that performance bugs don’t receive very hi… rules can be established. I have assigned Inaam as the InnoDB scalability engineer. We do not have much resources for scalability… not showed up in “show innodb statusâ€. select * from table where id=5 show innodb status: Hash table size 10624987, used…
Post: How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
… better to understand how Innodb recovery works. When Innodb recovers from logs it finds the last checkpoint time. Innodb has fuzzy checkpointing and… the cache and so having pretty scattered updates instead updating view counter for popular movie hundreds of times per second. Database… expect system to handle and crash Innodb few times to see how long it takes Innodb to recover. I’d recommend to…
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 3 Comments
… it is easy to check: mysql> select * from information_schema.innodb_rseg; +———+———-+———-+———+————+———–+ | rseg_id | space_id | zip_size | page_no | max… the data, it even can be seen in SHOW INNODB STATUS: Trx read view will not see trx with id >= F58464, sees…
Post: InnoDB benchmarks
January 3, 2007 By 15 Comments
…-innodb and next startup options were used: libexec/mysqld –no-defaults –user=root –innodb-buffer-pool-size=1500M –innodb-log-file-size=100M –innodb… and used queries is avaiable here: http://docs.google.com/View?docid=d7fzh8b_7dwd8m7 or on our page http://www.mysqlperformanceblog… or on our page http://www.mysqlperformanceblog.com/files/benchmarks/innodb_scale.html (Note: This benchmark is synthetic micro benchmarks focusing…
Post: When does Innodb Start Transaction ?
January 11, 2011 By 9 Comments
… however wrong answer from engine point of you. Run “SHOW INNODB STATUS” and you will see “not started” status in transaction… thread id 112, query id 411 localhost root show innodb status Trx read view will not see trx with id >= F56AEE, sees… this mode will NOT start transaction however reading or writing Innodb table will. I would call it delayed transaction creation – having…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
… outstanding IO requests to the disk. Lets look at SHOW INNODB STATUS: ——– FILE I/O ——– I/O thread 0 state: waiting… / 1000 ————– ROW OPERATIONS ————– 8 queries inside InnoDB, 3 queries in queue 12 read views open inside InnoDB Main thread process no. 3956, id… in this project from MySQL AB side) – to improve how Innodb read-ahead works by having more overlap between requests so…
