Huge +1 from me. One more SO question about LOCAL caches - https://stackoverflow.com/questions/49051079/is-it-possible-to-perform-sql-query-with-distributed-join-over-a-local-cache-and
"It is not possible to perform joins (both distributed an co-located) between LOCAL and PARTITIONED caches. The workaround is to use two PARTITIONED caches." В Ср, 25/07/2018 в 10:52 +0300, Stanislav Lukyanov пишет: > Hi Igniters, > > I’d like to start a discussion about the deprecation of the LOCAL caches. > > LOCAL caches are an edge-case functionality > I haven’t done any formal analysis, but from my experience LOCAL caches are > needed very rarely, if ever. > I think most usages of LOCAL caches I’ve seen were misuses: the users > actually needed a simple HashMap, or an actual PARTITIONED cache. > > LOCAL caches are easy to implement on top of PARTITIONED > If one requires a LOCAL cache (which is itself questionable, as discussed > above) it is quite easy to implement one on top of PARTITIONED cache. > A node filter of form `node -> node.id().equals(localNodeId)` is enough to > make the cache to be stored on the node that created it. > Locality of access to the cache (i.e. making it unavailable from other nodes) > can be achieved on the application level. > > LOCAL caches are hard to maintain > A quick look at the open issues mentioning “local cache” suggests that this > is a corner case for implementation of many Ignite features: > https://issues.apache.org/jira/issues/?jql=text%20~%20%22local%20cache%22%20and%20%20project%20%3D%20IGNITE%20and%20status%20%3D%20open > In particular, a recent SO question brought up the fact that LOCAL caches > don’t support native persistence: > https://stackoverflow.com/questions/51511892/how-to-configure-persistent-storage-for-apache-ignite-cache > Having to ask ourselves “how does it play with LOCAL caches” every time we > write any code in Ignite seems way to much for the benefits we gain from it. > > Proposal > Let’s deprecate LOCAL caches in 2.x and remove them in 3.0. > As a part of deprecation let’s do the following: > - Put @Deprecated on the CacheMode.LOCAL > - Print a warning every time a LOCAL cache is created > - Remove all mentions of LOCAL caches from readme.io, if any, except for the > page about cache modes > - On the page about cache modes explain that LOCAL is deprecated and can be > replaced with a PARTITIONED cache with a node filter > > Thanks, > St
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