ID | IEP-36 |
Author | Denis Magda |
Sponsor | Denis Magda |
Created |
|
Status | DRAFT |
Ignite codebase and release packages mix both core capabilities with 3rd party integrations. It leads to the following:
The goal of the IEP is to solve these challenges by doing the following:
Below you can find a definition of Ignite core, list of modules to be supported by the community and integrations that will go out of the community control.
Ignite core is a set of features and components that define the project's key capabilities and benefits such as a distributed memory-centric storage, RDBMS acceleration, transactions, and more. Most of such components are developed from scratch by the community and have minimal dependencies on 3rd parties:
Ignite modules are integrations that will be developed, supported, and released by Ignite community. Such integrations are important ones and have either significant or growing demand. Presently, the list is as follows:
Each module has to satisfy the following criteria:
A module needs to be released and packaged in the form of:
Even though the modules are released and packaged separately, there has to be an easy way to move modules' binaries to the Ignite core folder:
Thin clients are a special type of Ignite modules:
Thin clients should be stored in separate repositories and packaged in different forms - binaries, Maven/Nuget/Npmjs (depending on a language type). The clients can be released independently off the core.
Below is a list of existing integrations that won't be turned into Ignite modules but rather would be moved to separate Github repositories and won't be maintained by Ignite community for every core release. If later the community sees demand for an unsupported integration, it can be taken back and be officially supported (testing, dev, releases, compatibility with the core) as an Ignite module.
The list of integrations that to be moved to independent Github repositories and will not be supported by the community for every Ignite release:
Integration Name | +1 (explain if needed) | -1 (with explanation) |
---|---|---|
Denis Magda - that's a side project for apps that use Twitter. | ||
ZeroMQ | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all streaming tools/modules should be kept in one place (as part of AI or as Streaming AI separate project) |
RocketMQ | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all streaming tools/modules should be kept in one place (as part of AI or as Streaming AI separate project) |
Storm | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all streaming tools/modules should be kept in one place (as part of AI or as Streaming AI separate project) |
Flume | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all ETL tools/modules should be kept in one place (as part of AI or as ETL AI separate project) I mean that Flume is tool for loading big datasets to AI |
Flink | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all streaming tools/modules should be kept in one place (as part of AI or as Streaming AI separate project) |
MQTT | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | |
Camel | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | |
Hibernate | Denis Magda - Spring Data gets much bigger adoption for Ignite deployments. Don't see a lot of traction with Hibernate. It's hard to maintain it in various variations - Ignite goes with several modules of different versions. Better to have as an independent Github project with forks for specific Hibernate versions. | Alexey Zinoviev - I suppose it's useful feature for wide adoption among Java Devs who use AI not like cache, but like database |
JMS | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. | Alexey Zinoviev - all streaming tools/modules should be kept in one place (as part of AI or as Streaming AI separate project). Also, I didn't see the Kafka Integration in this list |
AOP-Based Grid | Denis Magda - low usage, better to have as an independent Github project that can be maintained by anybody. Alexey Goncharuk Maybe drop it at all because moving this into a separate project may be a pain - a lot of internal API usages | |
JSR-107(JCache) | Denis Magda - don't see any value in supporting this JSR rather than claiming that specification. It's better to have much cleaner Ignite key-value API without any dependencies influenced by the specification. | Alexey Zinoviev we should ask about that question the user-community, I have heard many times that that the JCache implementation is important for Java Devs |
OSGi | Denis Magda - this integration is already broken and badly maintained. Haven't come across anybody who uses OSGi in the projects Ignite is targeted for. | |
YARN | Denis Magda - not sure it's useful any longer and should be supported by the community. Alexey Zinoviev What was the purpose of this integration? | |
Mesos | Denis Magda - not sure it's useful any longer and should be supported by the community. Alexey Zinoviev What was the purpose of this integration? | |
.NET: Legacy Entity Framework and ASP.NET integrations | Denis Magda - outdated, needs to be replaced with a new one version. Pavel Tupitsyn integrations with legacy technologies; also blocks .NET Core migration | |
Scalar | Alexey Goncharuk Not used, brings unnecessary dependency on scala, adds library conflicts |
The list of the integrations to be removed completely (don't even move them to an independent Github repo):
Integration | +1 (explain if needed) | -1 (with explanation) |
---|---|---|
Redis and Memcached protocols support | Denis Magda - not sure why these 2 were supported in the first place. Sergey Kozlov - thin clients provide full and rich replacement | |
ignite-clients module | Denis Magda - we already have Thin Clients, duplicate features with fewer capabilities | |
Denis Magda - community has already voted for the removal. | The community has already voted for the removal. Alexey Zinoviev IGFS should be moved to the separate package in the first | |
AOP-Based Grid | Alexey Goncharuk Unused, hard to move to a separate module due to many internal API usages | |
Ignite Schedule | Alexey Goncharuk same issues as with local caches Sergey Kozlov - it can be implemeted in user code Pavel Kovalenko Ignite integration with distributed schedulers like Airflow or Oozie can be a better decision. |
As part of the modularization, that needs to be considered for Ignite 3.0, it's worthwhile listing all the APIs that the community is planning to remove in Ignite 3.0. The APIs can belong to both Ignite core and modules that will stay in Ignite and will be officially supported by the community:
API | +1 (explain if needed) | -1 (with explanation) |
---|---|---|
Already deprecated APIs | ||
Local caches | Alexey Kuznetsov Can we "emulate" local cache by partitioned with "node filter to one node"? Alexey Goncharuk Local cache is meaningless in a distributed system, especially when a transaction is involved: suppose a prepare step completed and a node with local cache goes down. According to 2PC, we cannot proceed until the node goes up again | |
Spatial indexes | Denis Magda - the API is broken and not suited for production. Can be designed from scratch with Ignite 3.1 and 3.2. | Alexey Zinoviev It could be removed only in the 3.1 then the new implementation will be provided in other case we will poor with indices |
Full-text search | Denis Magda - the API is broken and not suited for production. Can be designed from scratch with Ignite 3.1 and 3.2. | Alexey Zinoviev It could be removed only in the 3.1 then the new implementation will be provided in other case we will poor with full-text indices |
Checkpointing SPI | Denis Magda - Ignite caches/tables can be used to store the checkpoints. This API is redundant. | |
Ignite.lock | Alexey Goncharuk The distributed lock concept is broken (see corresponding Aphyr video). The usual lock usage pattern is lock - update cache - unlock. The same semantics can be achieved using pessimistic transactions with keys locking, but instead, for an end-user, it is clear how lock can fail in a distributed system (transaction rollback). Pavel Kovalenko Very fragile API. Not tested well. Some failures can lead to unavailability of controlling such locks. Can be returned back and reworked after implementation of some consensus algorithm like Raft. | Denis Magda - unless an alternate solution is provided as part of existing Transactional APIs. There has to be a clear migration guide for Ignite.lock customers. Alexey Zinoviev It could be removed only in the 3.1 then the new implementation will be provided |
Cache.lock | Alexey Goncharuk Same arguments as with Ignite.lock, but even more redundant API | Alexey Zinoviev It could be removed only in the 3.1 then the new implementation will be provided |
Ignite Data Structures | Pavel Kovalenko Can be marked as not safe and reworked after implementation of some consensus algorithm like Raft. | Denis Magda - that's basic functionality of every IMDG and in-memory cache. We can't remove it. Instead, let's plan through activities that improve or reconsider current implementations. Alexey Zinoviev Agree with Denis Magdaalso we should extend the list of basic structures (ready to help) |
GAR files | Denis Magda - to be replaced with JARs | |
"Force server mode" for client nodes | Denis Magda - don't see any value any longer. Alexey Goncharuk Already deprecated | |
Daemon nodes | Denis Magda - Visorcmd has to be preserved and updated to another protocol Alexey Kuznetsov - Visorcmd should be merged with controls.sh | |
CacheRebalanceMode.NONE and Rebalance Delay | Denis Magda - it can break data consistency in a cluster. Also, remove force rebalance mode as it can be used only if rebalance delay is set. Alexey Goncharuk The mode does not make sense, cannot be explained to an end-used | |
Indexing SPI | Denis Magda - it's highly unlikely that anybody used this. The community supports all the querying engines on its own. | |
QueryEntities and Annotations based configuration of SQL | Denis Magda - Alexey Goncharuk is going to propose an alternate API that unites these concepts. Sergey Kozlov - require full redesign, it should be fully compatible JDBC SQL and visa-versa | |
@CentralizedAffinityFunction | Alexey Goncharuk This API is no longer needed after exchange merge was introduced |
http://apache-ignite-developers.2346864.n4.nabble.com/Ignite-Modularization-td42486.html
This initiative is also related to the discussion of Apache Ignite APIs update/removal - Apache Ignite 3.0 Wishlist
// Links or report with relevant JIRA tickets.