Lets move on with SQL schema == Ignite cache. It worked always like this, I see no reasons to change this.
Sergi 2017-01-13 11:20 GMT+03:00 Vladimir Ozerov <voze...@gridgain.com>: > "Tablespace" (Oracle, PostgreSQL) is what maps better than "schema" to our > cache. But not ideally still. > > On Fri, Jan 13, 2017 at 11:10 AM, Vladimir Ozerov <voze...@gridgain.com> > wrote: > > > Alex, > > > > Currently Ignite is not used as database. It is used as search engine - > > several types, several tables, several joins. This is why having "SCHEMA > == > > cache" was never a problem. Users have never build complex SQL > applications > > on top of Ignite. But we are going towards database. And my question > stands > > still - suppose it is Y2019, how is user going to migrate his database > > containing 20-30-50-100 tables in a single schema in Oracle to Ignite? > > > > Single cache for all tables? Doens't work - not flexible. Users will > > definitely require different cache modes, different co-location rules, > > different number of backups, etc.. > > Schema per table? Doesn't work either - unmanageable and not convenient > > for users even for relatively small databases. > > > > From user perspective schema is logical grouping of database objects, > > nothing more. > > > > For Ignite schema could be a logical group of resources (nodes, memory > > pools, caches, etc.). And multiple tables over multiple caches should > > reside in it. To the contrast, table definition governs how data is > stored. > > This is similar to, for example, MySQL approach, where you define how you > > store data on per-table level, and on schema level you define only minor > > things like collation. > > > > Vladimir. > > > > > > On Fri, Jan 13, 2017 at 10:33 AM, Alexander Paschenko < > > alexander.a.pasche...@gmail.com> wrote: > > > >> Vova, > >> > >> 2017-01-13 4:56 GMT+08:00 Vladimir Ozerov <voze...@gridgain.com>: > >> > I am not quite sure I understand the idea of "SCHEMA == cache". > Consider > >> > some small database with, say, ~30 tables. And user wants to migrate > to > >> > Ignite. How is he supposed to do so? 30 schemas leading to rewrite of > >> all > >> > his SQL scripts? Or 30 key-value pairs in a single cache leading to > >> lack of > >> > flexibility and performance problems? > >> > >> But currently schema *is* semantically equal to cache while table is > >> equal to type descriptor (i.e. type of stored entities), nothing new > >> here. > >> > >> Say, in single cache we may have entities of types Person and > >> Organization, those map to two tables with same names, and can be > >> accessed within the same cache (i.e. schema). > >> > >> If we want to limit the user with having single type descriptor per > >> cache (i.e. cache has only one type of stored entities - BTW, where we > >> are with this 2.0-wise?), then this notion could change. But currently > >> what has been suggested already fits quite good with what we do have > >> at the moment regarding semantic of SQL objects. > >> > >> - Alex > >> > >> > Another example is how to deal with referene tables? Lots database has > >> > small reference tables which is best to fit REPLICATED cache, while > >> others > >> > are usually bound to PARTITIONED mode. "SCHEMA == cache" will force > >> users > >> > to split them into separate schemes leading to poor user experience. > >> > > >> > I understand that we may have some implementation details around it at > >> the > >> > moment. But from user perspective "SCHEMA == cache" doesn't make > sense. > >> As > >> > we are going towards AI 2.0 we'd better to rethink this approach. > >> > > >> > On Thu, Jan 12, 2017 at 11:46 PM, Denis Magda <dma...@apache.org> > >> wrote: > >> > > >> >> > >> >> > On Jan 12, 2017, at 12:35 PM, Dmitriy Setrakyan < > >> dsetrak...@apache.org> > >> >> wrote: > >> >> > > >> >> > On Thu, Jan 12, 2017 at 9:47 AM, Sergi Vladykin < > >> >> sergi.vlady...@gmail.com> > >> >> > wrote: > >> >> > > >> >> >> The xml config was only for example. We can put in this > >> configuration > >> >> >> string cache config parameters directly like this: > >> >> >> > >> >> >> CREATE SCHEMA "MyCacheName" WITH > >> >> >> "cacheMode=REPLICATED;atomicityMode=ATOMIC" > >> >> >> > >> >> > > >> >> > This approach makes sense, if it can be easily supported with H2. > >> >> > >> >> What’s for affinity keys? Can we make an exception for them by > >> defining in > >> >> this part of the statement > >> >> > >> >> CREATE TABLE employee ( > >> >> id BIGINT PRIMARY KEY, > >> >> dept_id BIGINT AFFINITY KEY, > >> >> name VARCHAR(128), > >> >> ); > >> >> > >> >> or that l > >> >> > >> >> CREATE TABLE employee ( > >> >> id BIGINT PRIMARY KEY, > >> >> dept_id BIGINT, > >> >> name VARCHAR(128), > >> >> CONSTRAINT affKey AFFINITY KEY(dept_id) > >> >> ); > >> >> > >> >> ? > >> >> > >> >> — > >> >> Denis > >> >> > >> >> > >> > > > > >
