Yes - avoiding an Ignite out of memory condition is exactly what I'm trying to do. The question is - how can I do this if memory metrics aren't reliable?
Does anyone have experience of successfully monitoring contracting Ignite memory consumption? Or does anyone have any more general thoughts on how to avoid IOOM other than using native persistence? To be clear, the problem with the metrics is not caused by the IOOM condition. See the amended example below: package mytest; import org.apache.ignite.DataRegionMetrics; import org.apache.ignite.Ignite; import org.apache.ignite.IgniteCache; import org.apache.ignite.Ignition; import org.apache.ignite.configuration.CacheConfiguration; import org.apache.ignite.configuration.DataRegionConfiguration; import org.apache.ignite.configuration.DataStorageConfiguration; import org.apache.ignite.configuration.IgniteConfiguration; import org.apache.ignite.failure.NoOpFailureHandler; import org.junit.Test; public class MemoryTest2 { private static final String CACHE_NAME = "cache"; private static final String DEFAULT_MEMORY_REGION = "Default_Region"; private static final long MEM_SIZE = 100L * 1024 * 1024; @Test public void testOOM() throws InterruptedException { try (Ignite ignite = startIgnite("IgniteMemoryMonitorTest1")) { fillDataRegion(ignite); CacheConfiguration<Object, Object> cfg = new CacheConfiguration<>(CACHE_NAME); cfg.setStatisticsEnabled(true); IgniteCache<Object, Object> cache = ignite.getOrCreateCache(cfg); // Clear all entries from the cache to free up memory memUsed(ignite); cache.clear(); cache.removeAll(); cache.put("Key", "Value"); memUsed(ignite); cache.destroy(); Thread.sleep(5000); // Should now report close to 0% but reports 59% still memUsed(ignite); } } private Ignite startIgnite(String instanceName) { IgniteConfiguration cfg = new IgniteConfiguration(); cfg.setIgniteInstanceName(instanceName); cfg.setDataStorageConfiguration(createDataStorageConfiguration()); cfg.setFailureHandler(new NoOpFailureHandler()); return Ignition.start(cfg); } private DataStorageConfiguration createDataStorageConfiguration() { return new DataStorageConfiguration() .setDefaultDataRegionConfiguration( new DataRegionConfiguration() .setName(DEFAULT_MEMORY_REGION) .setInitialSize(MEM_SIZE) .setMaxSize(MEM_SIZE) .setMetricsEnabled(true)); } private void fillDataRegion(Ignite ignite) { byte[] megabyte = new byte[1024 * 1024]; IgniteCache<Object, Object> cache = ignite.getOrCreateCache(CACHE_NAME); for (int i = 0; i < 50; i++) { cache.put(i, megabyte); memUsed(ignite); } } private void memUsed(Ignite ignite) { DataRegionConfiguration defaultDataRegionCfg = ignite.configuration() .getDataStorageConfiguration() .getDefaultDataRegionConfiguration(); String regionName = defaultDataRegionCfg.getName(); DataRegionMetrics metrics = ignite.dataRegionMetrics(regionName); float usedMem = metrics.getPagesFillFactor() * metrics.getTotalAllocatedPages() * metrics.getPageSize(); float pctUsed = 100 * usedMem / defaultDataRegionCfg.getMaxSize(); System.out.println("Memory used: " + pctUsed + "%"); } } -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/