javaignitegridgain

How to specify partition count on cache creation using Ignite thin client?

We are using Ignite cache in application. Multiple instances joins into topology, where caches created using Ignite.getOrCreateCache() with RendezvousAffinityFunction for partitioning like:

public static IgniteCache<String, Value> getOrCreateCache(Ignite ignite, String cacheName, int partitionCount) {
        return ignite.getOrCreateCache(
                new CacheConfiguration<String, Value>(cacheName)
                        .setGroupName("group")
                        .setBackups(0)
                        .setCacheMode(CacheMode.PARTITIONED)
                        .setAtomicityMode(CacheAtomicityMode.ATOMIC)
                        .setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC)
                        .setAffinity(new RendezvousAffinityFunction(true, partitionCount))
               );
    }

I am migrating application from thick client to thin client, thus using IgniteClient.getOrCreateCache() like:

    public static ClientCache<String, Value> getOrCreateCache(IgniteClient igniteClient, String cacheName, int partitionCount) {
        return igniteClient.getOrCreateCache(
                new ClientCacheConfiguration()
                        .setName(cacheName)
                        .setGroupName("group")
                        .setBackups(0)
                        .setCacheMode(CacheMode.PARTITIONED)
                        .setAtomicityMode(CacheAtomicityMode.ATOMIC)
                        .setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC)
                        // .setAffinity() ???
                );
    }

I am struggling of finding more info about configuring cache over IgniteClient, either in documentations or sources. As I could find, thin client supports partition awareness, and can distribute cache operations over nodes. How many partition would be created on cache that way, and why isn't it configurable?

Solution

  • NOTE: As the other answer explains, you don't need to change the default number in 99% use cases.

    With that said, partition count is provided by the affinity function. You can set it like this:

    CacheConfiguration<Object, Object> cacheCfg = new CacheConfiguration<>("cache-1")
        .setAffinity(new RendezvousAffinityFunction().setPartitions(512));

    However, custom affinity can't be set from the client side (for technical reasons - affinity function can have custom implementation and would require code deployment).

    Workarounds: