Hi Litao, Initially with first time count(*) , it used to take around 32seconds as it used to load into cache, and second time query takes 1.5sec to 2 i think, so with pre-prime we can achieve more improvement in first time query.
Regards, Akash On 2019/08/21 03:03:55, tao li <litao_xid...@126.com> wrote: > hi Akash, > Before development, we need to know how much improvement can be made to > queries by caching part of the index in advance. > We need to compare the first and second query and analyze them. We need > to find time differences for several important steps. > It can analyze the performance improvement that can be brought by > caching part of the index in advance. > > On 2019/08/15 12:03:09, Akash Nilugal <akashnilu...@gmail.com> wrote: > > Hi Community, > > > > Currently, we have an index server which basically helps in distributed > > caching of the datamaps in a separate spark application. > > > > The caching of the datamaps in index server will start once the query is > > fired on the table for the first time, all the datamaps will be loaded > > > > if the count(*) is fired and only required will be loaded for any filter > > query. > > > > > > Here the problem or the bottleneck is, until and unless the query is fired > > on table, the caching won’t be done for the table datamaps. > > > > So consider a scenario where we are just loading the data to table for > > whole day and then next day we query, > > > > so all the segments will start loading into cache. So first time the query > > will be slow. > > > > > > What if we load the datamaps into cache or preprime the cache without > > waititng for any query on the table? > > > > Yes, what if we load the cache after every load is done, what if we load > > the cache for all the segments at once, > > > > so that first time query need not do all this job, which makes it faster. > > > > > > Here i have attached the design document for the pre-priming of cache into > > index server. Please have a look at it > > > > and any suggestions or inputs on this are most welcomed. > > > > > > https://drive.google.com/file/d/1YUpDUv7ZPUyZQQYwQYcQK2t2aBQH18PB/view?usp=sharing > > > > > > > > Regards, > > > > Akash R Nilugal > > >
