2014-08-13 13:59 GMT+02:00 MauMau <maumau...@gmail.com>: > From: "Pavel Stehule" <pavel.steh...@gmail.com> > > isn't it too heavy? >> > > Are you concerned about the impactof collection overhead on the queries > diagnosed? Maybe not light, but I'm optimistic. Oracle has the track > record of long use, and MySQL provides performance schema starting from 5.6.
partially, I afraid about total performance (about impact on IO) - when we use a usual tables, then any analyses without indexes are slow, so you need a indexes, and we cannot deferred index update. You should thinking about retention policy - and without partitioning you got massive deletes. So I cannot to imagine a usage of table based solution together with some higher load. Our MVCC storage is not practical for storing only inserted data, and some custom storage has no indexes - so this design is relative big project. > > > I have just terrible negative experience with Vertica, where this design >> is >> used - almost all information about queries are available, but any query >> to >> related tables are terrible slow, so I am inclined to more simple design >> oriented to log based solution. Table based solutions is not practical >> when >> you exec billions queries per day. I understand to motivation, but I >> afraid >> so it can be very expensive and slow on highly load servers. >> > > Which do you mean by "query related to tables", the queries from > applications being diagnosed, or the queries that diagnose the performance > using statistics views? > > Could you elaborate on your experience with Vertica? That trouble may be > just because Vertica's implementation is not refined. > > sure - Vertica is not mature database. More it has only one storage type optimized for OLAP, what is wrong for long catalog, and for working with performance events too. > I understand the feeling of being inclined to log based solution for its > implementation simplicity. However, the server log is difficult or > impossible to access using SQL queries. This prevents the development of > performance diagnostics functionality in GUI administration tools. Also, > statistics views allow for easy access on PAAS like Amazon RDS and Heroku. > I prefer a possibility to read log via SQL (maybe some FDW) than use tables for storing log. These tables can be relative very large in few days - and we cannot to write specialized engine like MySQL simply. Pavel > > Regards > MauMau > >
