…longer queries. What should you do if you need to update a lot of rows ? Use Query Chopping – this can be running update…UPDATE Example: UPDATE posts SET spam=1 WHERE body LIKE “%cheap rolex%”; This query will perform full table scan in MySQL 5.0…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
…mysql [localhost] {msandbox} (test) > update idxtest set i2=i1; Query OK, 10900996 rows affected (6 min 47.87 sec) Rows… 1 row in set (0…takes about 5 times longer even though in case of full table scan about 50 times more rows…
Post: Comparing Percona XtraDB Cluster with Semi-Sync replication Cross-WAN
June 14, 2012 By 7 Comments
…rows, and calculated an average time for each INSERT to autocommit. Environment Results (ms) Control 0…longer than local binary log writing. It seems conceivable to me that this may be improvable by some Galera tuning. UPDATE…significant. Semi-sync, as expected, takes approximately 1 RTT for … MySQL…
