Поиск ошибок желательно осуществлять по их коду, так как описания и названия могут меняться от релиза к релизу MySQL. В настоящий момент в базе хранятся только имя ошибки, описание на английском и описание на ломанном русском, в дальнейшем планируется улучшение русского перевода и добавления путей решений и устранения ошибок с различных форумов на просторах интернета. Они разделяются на два типа: первые — это ошибки на стороне сервера и вторые ошибки у клиента, клиентской программы. Расшифровка кодов ошибок MySQL. Диапазон допустимых кодов от mysql query cache size 1001 и до 2059.
Enabling MySQL Query Cache. A query cache size that. In this case, the server does not acquire the query cache mutex at all, which means that the query cache cannot be enabled at runtime and there is reduced overhead in query execution. Raising the query cache size didn’t really help. Avoid comment (and space) in the start of the query – Query Cache does simple optimization to check if query can be cached. This is achieved using a default size of 1M, with a default for query_cache_type of 0. Now setup cache size 16Mb: mysql> SET
GLOBAL query_cache_size = 16777216;. Looking at performance I’ve seen query cache offering about double performance for simple queries with select done by primary key, obviously there is no upper boundary – Very complex queries producing small result set will be offering best speed up. Расшифровка кодов ошибок MySQL. Now the problem is when you say that Stored functions still cannot be cached does that include stored procedures too. First looking at number of your selects – Com_select and see how many of them are cached. The
query_cache_size specifies the size of the cache, you may run some . Well honestly speaking if performance would be problem I should have started with full page caching rather than MySQL level caching but it is other story. If most of your queries have large results (check the Qcache_total_blocks and Qcache_queries_in_cache status variables), you can increase performance by increasing query_cache_min_res_unit. In your case you’re getting a lot of updates so queries could be constantly invalidated. Id=21051 has improved the reset query cache operation and caused it to be less likely to block other queries in 5. Derek, you’re right I didn’t add that test to graphic so I ran it a quick test and I can’t see any activity reported in performance_schema (where Grafana reads data from) but I still see status counters increasing. TYPE = ‘DATA_SOURCE_TYPE’
join db_two. This post is describing some of them:
http://www. Optimizing mysql query cache for WordPress sites
Query OK, 0 rows . It does not cache the plan but full result sets. Don’t cache results in or retrieve results from the query cache. One of the most misconfigured MySQL performance features, is MySQL Query Cache Size. Be cautious about sizing the query cache excessively large, which increases the overhead required to maintain the cache, possibly beyond the benefit of enabling it. Depending on the types of queries your server executes, you might find it helpful to tune the value of query_cache_min_res_unit:. Query OK, 0 rows . Now let us think about how to decide the MySQL query cache size:. You mentioned that FLUSH QUERY CACHE needs to be run to defragment the free blocks. Basically MySQL spends more time grooming the cache the bigger the cache is and since the cache is very volatile under even moderate write loads (queries gets cleared often), putting it too large will have an adverse effect on your application performance