Slow Performance Of Combined Mysql Queries Stack Overflow I have 2 queries that run very fast when ran separately, but when combined by using one of them as a subquery, the performance degrades drastically. fast query i: select distinct p.products image. I have two mysql queries that run very fast, but when i combine them the new query is very slow. fast (<1 second, 15 results): select distinct id, name, company id from people where company i.
Php Strange Slow Queries With Mysql Stack Overflow Using a subquery to fetch the 100 id's increased performance to 14 seconds, but that is still far too long. the optimizations i have tried so far have all shortened the time a bit, but i feel that they are not getting at the root of the problem. here is the explain for the subquery approach. While mysql can use multiple indexes in a query, it chooses one that may not be optimal. see this thread, specifically the accepted answer. you may benefit from indexing (status, gender, birthday). the first and second queries are, in fact, identical. Since 10% of the table meets the single criteria, the optimizer may decide that it is faster to scan the table rather than bounce back and forth between the index and the data. please provide show create table and explain select. Uses temporary filesort, 92 lines, and runs in 30ms. similarly fast if i modify the query to search for the same ip in the dst column. but if i combine both queries to search for that ip in the xlatedst or the dst columns: firewall.name as fw, proto.proto, service, action.action, . sum(count) as hits, max(date) as lastused, rule uid.rule uid .
Mysql Improve Slow Query Performance Stack Overflow Since 10% of the table meets the single criteria, the optimizer may decide that it is faster to scan the table rather than bounce back and forth between the index and the data. please provide show create table and explain select. Uses temporary filesort, 92 lines, and runs in 30ms. similarly fast if i modify the query to search for the same ip in the dst column. but if i combine both queries to search for that ip in the xlatedst or the dst columns: firewall.name as fw, proto.proto, service, action.action, . sum(count) as hits, max(date) as lastused, rule uid.rule uid . Using mysql 5.6, i'm noticing that combined select queries (e.g. select x.a from x x where x.b in (select y.b from y y where y.c = 'something')) are way slower than doing two separate queries, using the results of the first query in the in clause of the second query. Consistent query execution speed is more likely to be achieved when the dealloc and close counts are closer to the respective prepared counts. general log capture and analysis will confirm the resources were left in use and not deallocated or closed. I've made a php script which exactly does what i want, but it's extremely slow on the server. when i'm testing it locally, runtime is about 60 80 ms for the whole script. when i run it on my webserver it takes about 4 seconds. but i can't get clear what the problem on the webserver is. I am working on a search app that queries a large amount of info (100m rows) with multiple filters that can be used and i am having trouble getting it to perform when multiple filters are combined.
Mysql Is Slow In Executing Queries Stack Overflow Using mysql 5.6, i'm noticing that combined select queries (e.g. select x.a from x x where x.b in (select y.b from y y where y.c = 'something')) are way slower than doing two separate queries, using the results of the first query in the in clause of the second query. Consistent query execution speed is more likely to be achieved when the dealloc and close counts are closer to the respective prepared counts. general log capture and analysis will confirm the resources were left in use and not deallocated or closed. I've made a php script which exactly does what i want, but it's extremely slow on the server. when i'm testing it locally, runtime is about 60 80 ms for the whole script. when i run it on my webserver it takes about 4 seconds. but i can't get clear what the problem on the webserver is. I am working on a search app that queries a large amount of info (100m rows) with multiple filters that can be used and i am having trouble getting it to perform when multiple filters are combined.
Slow Performance Of Search Results Php Mysql Queries Stack Overflow I've made a php script which exactly does what i want, but it's extremely slow on the server. when i'm testing it locally, runtime is about 60 80 ms for the whole script. when i run it on my webserver it takes about 4 seconds. but i can't get clear what the problem on the webserver is. I am working on a search app that queries a large amount of info (100m rows) with multiple filters that can be used and i am having trouble getting it to perform when multiple filters are combined.
Query Optimization Mysql Slow Queries With Multiple Conditions
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