Colin Cassidy created IGNITE-12096:
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Summary: Ignite memory metrics incorrect on cache usage contraction
Key: IGNITE-12096
URL: https://issues.apache.org/jira/browse/IGNITE-12096
Project: Ignite
Issue Type: Bug
Components: cache
Affects Versions: 2.7
Reporter: Colin Cassidy
When using the Ignite metrics API to measure available memory, the usage
figures appear to be accurate while memory is being consumed - but when memory
is freed the metrics do not drop. They appear to report that memory has not
been freed up, even though it has.
Reproducer below. This affects Ignite 2.7+.
{{}}{{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 + "%"); }}
{{ } }}
{{} }}
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