Ed, Could you please demonstrate how .NET node or .NET will change cache configuration with proposed API? Taking in count that XML is not available in most cases, and custom Java classes from cache configuration are available only on server nodes and only from Java.
ср, 21 нояб. 2018 г. в 18:36, Eduard Shangareev <eduard.shangar...@gmail.com >: > Vladimir, > > I don't see any difference here. > > The same possibilities would be available as with normal cache start: > -XML; > -remote node. > > >3) Avoid race condition when configuration changes between configuration > read and method call (what could lead to a number of strange effects). > > Well, we could add *old* configuration parameter for CAS-like semantic. > > On Wed, Nov 21, 2018 at 6:26 PM Vladimir Ozerov <voze...@gridgain.com> > wrote: > > > Ed, > > > > Caches in .NET could be started programmatically, from XML which .NET API > > has no access to, or dynamically from remote nodes (eg Java node). > > > > ср, 21 нояб. 2018 г. в 18:24, Eduard Shangareev < > > eduard.shangar...@gmail.com > > >: > > > > > Vladimir, > > > > > > How does .Net user start caches right now? > > > > > > On Wed, Nov 21, 2018 at 6:10 PM Vladimir Ozerov <voze...@gridgain.com> > > > wrote: > > > > > > > Eduard, > > > > > > > > Simple != correct. Let’s consider a simple use case: user want to > > change > > > > PARTITIONED -> REPLICATED from .NET, but do not some classes from > > > > CacheConfiguration. How do we solve this? > > > > > > > > Vladimir. > > > > > > > > ср, 21 нояб. 2018 г. в 18:02, Eduard Shangareev < > > > > eduard.shangar...@gmail.com > > > > >: > > > > > > > > > Vladimir, > > > > > > > > > > I propose not to change cache configuration in runtime but restart > > > cache > > > > > with the new compatible configuration on data which we have > > underfoot. > > > > > > > > > > What we could change: > > > > > -backup count; > > > > > -TRANSACTIONAL <-> ATOMIC; > > > > > -REPLICATED - PARTITIONED; > > > > > -other settings. > > > > > > > > > > So, yeah, it would be great to have a possibility to change some > > > > properties > > > > > in runtime. But right we don't any way to change anything except > > > indexes > > > > > and SQL fields. > > > > > > > > > > We already have all mechanism to do this. > > > > > The main issue is to make it reliable and exclude cases when we > could > > > > come > > > > > to the unrecoverable state. > > > > > > > > > > So, I suggest keeping the solution as simple as possible. > > > > > For indexes clashes and ClassNotFoundException we could revert > > > > > configuration update and start with the old configuration. > > > > > > > > > > > > > > > On Wed, Nov 21, 2018 at 5:44 PM Vladimir Ozerov < > > voze...@gridgain.com> > > > > > wrote: > > > > > > > > > > > Eduard, > > > > > > > > > > > > Got it. Please take the following things in count during design: > > > > > > > > > > > > 1) Two distinct PMEs might not work well. Consider a situation > > w1hen > > > I > > > > > > decided to move a cache with index "MY_INDEX" from schema A to > > schema > > > > B. > > > > > > While cache was stopped, another cache with index "MY_INDEX" was > > > > created > > > > > in > > > > > > schema B. Now first cache cannot start due to index name > conflict. > > > > > > 2) Cancelling index creation is also bad idea because this is > > > > potentially > > > > > > long operation. Instead, most likely that we should wait to > > > concurrent > > > > > > schema operations to finish first. That is, all operations on > cache > > > > > should > > > > > > be ordered wrt each other somehow > > > > > > 3) Why do we think that cache restart will be needed at all? We > > have > > > a > > > > > lot > > > > > > of configuration properties which could be changed safely either > > > > without > > > > > > PME or with a single PME. - rebalance properties, cache store > > > > properties > > > > > > (especially write-behind stuff), some query properties (e.g. > > "detail > > > > > > metrics"), etc.. In essence, it seems that >50% of properties > could > > > be > > > > > > changed without cache restart, other 25% will not be supported, > and > > > the > > > > > > rest may require restart. > > > > > > 4) Client nodes and thin client may not have necessary classes in > > > > > > classpath. E.g. consider a user which want to change rebalance > > > timeout > > > > > for > > > > > > cache, but do not have configured interceptor in classpath. With > > > > proposed > > > > > > API it will be impossible. This is especially true for non-Java > > > > clients. > > > > > > > > > > > > That said, I think we should consider another API which will not > > > > require > > > > > > full CacheConfiguration object. This might be a kind of builder > or > > > so. > > > > > And > > > > > > once user set properties he want to change to the builder, we can > > > > analyze > > > > > > them and either change them in runtime without PME, change with a > > > > single > > > > > > PME or change with full cache restart. > > > > > > > > > > > > What do you think? > > > > > > > > > > > > Vladimir. > > > > > > > > > > > > On Wed, Nov 21, 2018 at 5:01 PM Eduard Shangareev < > > > > > > eshangar...@gridgain.com> > > > > > > wrote: > > > > > > > > > > > > > Vladimir, > > > > > > > > > > > > > > 1) Affinity could be changed, but count of partition couldn't > be. > > > > > > > 2) So it would trigger 2 PME. Dynamic start and stop. > > > > > > > 3) In theory, should cancel them and new setting should be > > applied. > > > > How > > > > > > it > > > > > > > works now? Create an index and stop node, for example. > > > > > > > > > > > > > > On Wed, Nov 21, 2018 at 4:56 PM Vladimir Ozerov < > > > > voze...@gridgain.com> > > > > > > > wrote: > > > > > > > > > > > > > > > Hi Ed, > > > > > > > > > > > > > > > > Several questions from my side: > > > > > > > > 1) If we do not allow to change the most demanded by users > > things > > > > > like > > > > > > > > affinity or persistence/in-memory, then what kind of > > > configuration > > > > > > > > properties do we expect to be changed? Can we have several > > > > examples? > > > > > > > > 2) How will it interact with PME? > > > > > > > > 3) How will it interact with CREATE INDEX and ALTER TABLE > > > commands? > > > > > > > > > > > > > > > > On Wed, Nov 21, 2018 at 4:48 PM Eduard Shangareev < > > > > > > > > eduard.shangar...@gmail.com> wrote: > > > > > > > > > > > > > > > > > Igniters, > > > > > > > > > > > > > > > > > > I propose new public API to change the cache configuration > of > > > > > > > persistent > > > > > > > > > caches with keeping data. > > > > > > > > > > > > > > > > > > It would look like: > > > > > > > > > > > > > > > > > > Ignite ignite = ...; > > > > > > > > > ignite.restartCaches(cfg1, ... cfgN); > > > > > > > > > > > > > > > > > > where cfgX is a new cache configuration, which contains the > > > name > > > > of > > > > > > an > > > > > > > > > existing persistent cache. > > > > > > > > > > > > > > > > > > The obvious limitation: > > > > > > > > > - affinity key mapping couldn't be changed; > > > > > > > > > - count of partitions couldn't be changed; > > > > > > > > > - MVCC couldn't be turned off/on; > > > > > > > > > - persistent couldn't be turned off; > > > > > > > > > - group settings couldn't be changed (group name); > > > > > > > > > - if cache belongs to group it's needed to restart all of > > them. > > > > > > > > > > > > > > > > > > Failure scenario is the crucial thing (and most difficult): > > > > > > > > > - initiator fail; > > > > > > > > > - cluster restart at any stage; > > > > > > > > > - joining/starting offline nodes. > > > > > > > > > > > > > > > > > > Some thoughts about implementation: > > > > > > > > > - stop cache with destroy=false; > > > > > > > > > - start cache dynamically with new configuration; > > > > > > > > > - if indexes settings changed - remove index.bin to start > > > > > indexation; > > > > > > > > > - change blt-history when start cache initiated to not > allow > > > join > > > > > > nodes > > > > > > > > > with old configuration; > > > > > > > > > - use restartId (IGNITE-8911) to not allow to start cache > in > > > > > between. > > > > > > > > > > > > > > > > > > Your thoughts? Would it be a useful feature? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > Best regards, > > > > > > > Eduard. > > > > > > > > > > > > > > > > > > > > > > > > > > > >
