To avoid having to either hard-code or manually configure service addresses (possibly several dozen), and to reduce the project's dependency on docker to deal with routing and discovery, the option to use [Zookeeper](https://zookeeper.apache.org/) to manage services and discovery has been added.
A service registry interface was added, with a Zookeeper implementation and a basic implementation that only works on docker and hard-codes everything.
The last remaining REST service, the assistant-service, has been migrated to gRPC.
This also proved a good time to clear out primordial technical debt from the root of the codebase. The 'service-client' library has been taken behind the barn and given a last farewell. It's replaced by a small library for managing gRPC channels.
Since it's no longer used by anything, RxJava has been removed as a dependency from the project.
Although the current state seems reasonably stable, this is a work-in-progress commit.
IndexJournalWriterPagingImpl was modified to not page on number of entries written, but number of (equivalent uncompressed) bytes written.
Since the failure mode if too much data is written per file is quiet corruption of the index, the former behavior was extremely fragile. The new behavior should consistently ensure that the data is sufficiently small to not cause any integer rollovers.
The change in 6dcc20038c was reverted, as there is really no sane reason to have this configurable in software.
This turned out to be very difficult to do in small isolated steps.
* Design overhaul of the control gui using bootstrap
* Move the actors out of control-service into to a new executor-service, that can be run on multiple nodes
* Add node-affinity to message queue
... also move some common configuration into the root build.gradle-file.
Support for JDK21 in lombok is a bit sketchy at the moment, but it seems to work. This upgrade is kind of important as the new index construction really benefits from Arena based lifecycle control over off-heap memory.
* Reduce memory churn in LoaderIndexJournalWriter, fix bug with keyword mappings as well
* Remove remains of OldDomains
* Ensure LOADER_PROCESS_OPTS gets fed to the processes
* LinkdbStatusWriter won't execute batch after each added item post 100 items
This is a system-wide change. The index used to have a lexicon, mapping words to wordIds using a large in-memory hash table. This made index-construction easier, but it
also added a fairly significant RAM penalty to both the index service and the loader.
The new design moves to 64 bit word identifiers calculated using the murmur hash of the keyword, and an index construction based on merging smaller indices.
It also became necessary half-way through to upgrade guice as its error reporting wasn't *quite* compatible with JDK20.
This provides a much cleaner separation of concerns, and makes it possible to get rid of a lot of the gunkier parts of the index service. It will also permit lowering the Xmx on the index service a fair bit, so we can get CompressedOOps again :D
Deprecate the LoadUrl instruction entirely. We no longer need to be told upfront about which URLs to expect, as IDs are generated from the domain id and document ordinal.
For now, we no longer store new URLs in different domains. We need to re-implement this somehow, probably in a different job or a as a different output.
