Recently, Morgan has been writing on deprecating some My SQL features and inspired by that while working on My SQL on POWER, I wondered “What is the impact of the My SQL query cache on modern hardware?” We’ve known for over six years (since before we started Drizzle) that the query cache hurt performance.to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is NOT enabled. MEMORY USAGE Max Memory Ever Allocated : 650 M Configured Max Per-thread Buffers : 2.70 G Configured Max Global Buffers : 320 M Configured Max Memory Limit : 3.02 G Physical Memory : 2.00 G Max memory limit exceeds 90% of physical memory KEY BUFFER Current My ISAM index space = 52 M Current key_buffer_size = 256 M Key cache miss rate is 1 : 1710 Key buffer free ratio = 74 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 64 M Current query_cache_used = 29 M Current query_cache_limit = 1 M Current Query cache Memory fill ratio = 45.79 % Current query_cache_min_res_unit = 4 K My SQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 2 M Current read_rnd_buffer_size = 12 M Sort buffer seems to be fine JOINS Current join_buffer_size = 132.00 K You have had 225 queries where a join could not use an index properly You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log.You will not be able to do point in time recovery See THREADS Current thread_cache_size = 8 Current threads_cached = 7 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 151 Current threads_connected = 1 Historic max_used_connections = 18 The number of used connections is 11% of the configured maximum. If you are unable to optimize your queries you may want to increase your join_buffer_size to accommodate larger joins in one pass. This script will still suggest raising the join_buffer_size when ANY joins not using indexes are found.Hopefully this threat can grow and be useful to others in the future. In any case, output of recent is included here for your viewing enjoyment...
Or maybe you’d like to execute graceful switchovers and failovers, as your application does not handle broken transactions well? As we described in this previous post, Proxy SQL uses a concept of hostgroups - a group of different backends which serve the same purpose or handle similar type of traffic.
This is very valid question most of you are probably asking. Proxy SQL’s biggest advantage is this - it is a piece of software created by DBA’s, for DBA’s.
You either already are using some kind of proxy layer (be it HAProxy or Max Scale perhaps), or you have concluded that you don’t really need a proxy layer in your setup. It’s aim is to help with common, sometimes very frustrating problems.
Rene confirmed this in his post yesterday, but it has also previously been mentioned by Stewart Smith, Domas Mituzas (update: and Kristian Koehntopp).
Assuming that scalability could be improved, the limiting factor of the query cache is that since only queries that hit the cache will see improvement; it is unlikely to improve We concur with the research performed by Jiamin Huang, Barzan Mozafari, Grant Schoenebeck, Thomas F. We considered what improvements we could make to query cache versus optimizations that we could make which provide improvements to .