mnovoseltsev opened a new issue, #11907:
URL: https://github.com/apache/ignite/issues/11907
We have a simple 3 nodes cluster and we wanted to move read heavy data to
ignite and use near cache to optimize cache read operations. After PoC with
near caches we noticed that requested item not always saved in near cache even
though near cache limit is not yet reached. I have run a simple scenario:
Test scenario:
1. Simple 3 nodes ignite cluster on bare metal hosts with mostly default
configs:
- Ignite version 2.16 & 2.17
- Static discovery SPI of three IPs & ports
- Static communication SPI
- Discovery and Cache events are enabled
- Custom storage path for persistent regions
- two regions defined: default one is in memory:
- in memory with initial and max size set to 356/1024 MB and
RANDOM_2_LRU eviction
- persistent one with initial and max size set to 64/512MB
3. Having near cache created with limit of 100 items and FIFO expiry
4. Request 100 unique items from cache (items saved in cache from different
client)
5. Check near cache state with peaking it explicitly and simple get operation
I found the following behavior:
- Having partitioned cache with two copies - only around 30% of requested
items saved in cache. It is a complete random when item might be added to local
cache, it can be after 1 or after 10 requests
- when after couple of rounds of request of the same set of keys cache
finally gets full, switch to another set of keys causes eviction of items but
new keys again not always added, so local cache shrinks
- Having replicated cache has same results on the same 3 server nodes set-up
- Having partitioned cache with zero back-ups everything works as expected
- Having partitioned cache with back-ups with readFromBackup flag set to
false - works as expected
- Having replicated cache with copies with readFromBackup flag set to false
- properly saves to near cache but never reads from it when using plain get
method. But it works fine when using explicit peak into near cache
- In each scenario near cache properly saves items that are created from the
given client
- All scenarios work fine when all 3 servers and 1 client nodes are
collocates on single host
So my assumption is that near cache for whatever reason not saving entries
read from back-up partitions.
I have reviewed ignite documentation and haven't found any specific config
required for Near Cache to work. I wonder if you can help me to identify what
is wrong.
Sample cluster server config:
```java
IgniteConfiguration config = new IgniteConfiguration();
TcpDiscoveryVmIpFinder ipFinder = new TcpDiscoveryVmIpFinder()
.setAddresses(List.of("<host1.ip>:22222", "host2.ip:22222",
"host3.ip:22222"));
config.setDiscoverySpi(new TcpDiscoverySpi()
.setIpFinder(ipFinder)
.setLocalPort(22222)
.setLocalAddress(ipAddress)
.setLocalPortRange(0)
);
config.setCommunicationSpi(new TcpCommunicationSpi()
.setLocalPortRange(0)
.setLocalAddress(ipAddress)
);
config.getDataStorageConfiguration()
.setDefaultDataRegionConfiguration(
new DataRegionConfiguration()
.setInitialSize(356 * 1024 * 1024)
.setMaxSize(1024 * 1024 * 1024)
.setPageEvictionMode(DataPageEvictionMode.RANDOM_2_LRU)
).setDataRegionConfigurations(
new DataRegionConfiguration()
.setName("persistence")
.setInitialSize(64* 1024 * 1024)
.setMaxSize(512* 1024 * 1024)
.setPersistenceEnabled(true)
);
```
Sample cache config
```java
NearCacheConfiguration<Integer, String> nearCacheConfiguration = new
NearCacheConfiguration<>();
nearCacheConfiguration.setNearEvictionPolicyFactory(new
FifoEvictionPolicyFactory<>(100));
CacheConfiguration<Integer, String> cacheConfiguration = new
CacheConfiguration<>(cacheName);
cacheConfiguration
.setCacheMode(CacheMode.PARTITIONED)
.setBackups(2)
.setDataRegionName("persistence")
.setNearConfiguration(nearCacheConfiguration);
```
Depends if cache is already present or a not we use `ignite.createCache` or
`ignite.createNearCache`
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