# Why does heap memory increase? **URL:** \ **Category:** Elasticsearch\ **Created:** [June 13, 2021, 4:12pm UTC](https://discuss.elastic.co/t/why-does-heap-memory-increase/275768 "2021-06-13T16:12:37Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![jaeho](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@jaeho](https://discuss.elastic.co/u/jaeho)\ **Post date:** [June 13, 2021, 4:12pm UTC](https://discuss.elastic.co/t/why-does-heap-memory-increase/275768/1 "2021-06-13T16:12:38Z")
Hello. I am curious about the increase in memory usage even though the query traffic is low and the number of documents is small, and I would like expert opinions on how to tune the GC. [Servers (Nodes)] - Total: 4 Nodes (master: 1, data: 3) - CPU: Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz (40 cores) - MEM: 126GB [ElasticSearch] - Version: ES7.10.2 oss - Number of Shards: 4, - Number of Replicas: 1 - The number of indexed documents is about 20,000. - 1 request per 1 second. - 20,000 doucuments are updated only at 5am. (by batch) - store.size: 57mb - Not use Kibana, Logstash, Beats \*\* Scheme \*\*\* about 80 fields (indexed fields: 30) ```auto # Cluster API { - "_nodes": { - "total": 4, "successful": 4, "failed": 0 }, "cluster_name": "podcast1", "cluster_uuid": "OIlUdP3JQRuGvUpwodvnIw", "timestamp": 1623600113895, "status": "green", "indices": { - "count": 1, "shards": { - "total": 8, "primaries": 4, "replication": 1, "index": { - "shards": { - "min": 8, "max": 8, "avg": 8 }, "primaries": { - "min": 4, "max": 4, "avg": 4 }, "replication": { - "min": 1, "max": 1, "avg": 1 } } }, "docs": { - "count": 21292, "deleted": 0 }, "store": { - "size_in_bytes": 60097104, "reserved_in_bytes": 0 }, "fielddata": { - "memory_size_in_bytes": 0, "evictions": 0 }, "query_cache": { - "memory_size_in_bytes": 0, "total_count": 0, "hit_count": 0, "miss_count": 0, "cache_size": 0, "cache_count": 0, "evictions": 0 }, "completion": { - "size_in_bytes": 0 }, "segments": { - "count": 8, "memory_in_bytes": 128480, "terms_memory_in_bytes": 96384, "stored_fields_memory_in_bytes": 4160, "term_vectors_memory_in_bytes": 0, "norms_memory_in_bytes": 17536, "points_memory_in_bytes": 0, "doc_values_memory_in_bytes": 10400, "index_writer_memory_in_bytes": 0, "version_map_memory_in_bytes": 0, "fixed_bit_set_memory_in_bytes": 0, "max_unsafe_auto_id_timestamp": -1, "file_sizes": { - } }, "mappings": { - "field_types": [ - { - "name": "date", "count": 1, "index_count": 1 }, { - "name": "integer", "count": 11, "index_count": 1 }, { - "name": "keyword", "count": 21, "index_count": 1 }, { - "name": "long", "count": 8, "index_count": 1 }, { - "name": "text", "count": 39, "index_count": 1 } ] }, "analysis": { - "char_filter_types": [ - ], "tokenizer_types": [ - { - "name": "pattern", "count": 1, "index_count": 1 } ], "filter_types": [ - { - "name": "pattern_replace", "count": 1, "index_count": 1 } ], "analyzer_types": [ - { - "name": "custom", "count": 2, "index_count": 1 } ], "built_in_char_filters": [ - ], "built_in_tokenizers": [ - { - "name": "keyword", "count": 1, "index_count": 1 } ], "built_in_filters": [ - { - "name": "lowercase", "count": 2, "index_count": 1 } ], "built_in_analyzers": [ - ] } }, "nodes": { - "count": { - "total": 4, "coordinating_only": 0, "data": 4, "ingest": 4, "master": 4, "remote_cluster_client": 4 }, "versions": [ - "7.10.2" ], "os": { - "available_processors": 160, "allocated_processors": 160, "names": [ - { - "name": "Linux", "count": 4 } ], "pretty_names": [ - { - "pretty_name": "CentOS Linux 7 (Core)", "count": 4 } ], "mem": { - "total_in_bytes": 269138096128, "free_in_bytes": 44883550208, "used_in_bytes": 224254545920, "free_percent": 17, "used_percent": 83 } }, "process": { - "cpu": { - "percent": 0 }, "open_file_descriptors": { - "min": 360, "max": 368, "avg": 363 } }, "jvm": { - "max_uptime_in_millis": 14920332, "versions": [ - { - "version": "15.0.1", "vm_name": "OpenJDK 64-Bit Server VM", "vm_version": "15.0.1+9", "vm_vendor": "AdoptOpenJDK", "bundled_jdk": true, "using_bundled_jdk": true, "count": 4 } ], "mem": { - "heap_used_in_bytes": 9423393920, "heap_max_in_bytes": 68719476736 }, "threads": 661 }, "fs": { - "total_in_bytes": 2397027188736, "free_in_bytes": 1984199778304, "available_in_bytes": 1984199778304 }, "plugins": [ - { - "name": "es-klp-plugin", # Korean Analyzer "version": "1.12.5", "elasticsearch_version": "7.10.2", "java_version": "1.8", "description": "SKT klp - ES Plugin", "classname": "search.tech.plugin.KlpPlugin", "extended_plugins": [ - ], "has_native_controller": false } ], "network_types": { - "transport_types": { - "netty4": 4 }, "http_types": { - "netty4": 4 } }, "discovery_types": { - "zen": 4 }, "packaging_types": [ - { - "flavor": "oss", "type": "tar", "count": 4 } ], "ingest": { - "number_of_pipelines": 0, "processor_stats": { - } } } } ``` [JDK and JVM options] - Open JDK 15 (Bundled OpenJDK) - Use G1GC - Heap: ```auto # I didn't change anything other than the heap size. -Xms16g -Xmx16g 14-:-XX:+UseG1GC 14-:-XX:G1ReservePercent=25 14-:-XX:InitiatingHeapOccupancyPercent=30 ``` Query requests are about 1 per second and there are almost no updates of documents. I don't understand why the memory goes up to 60%. (And at 5am, heap memory usage increases about 10% point by batch of updating 20000 documents) ![memory_graph](https://us1.discourse-cdn.com/elastic/original/3X/0/2/023851296a2d462b0d7ade99a2771ca173e29131.jpeg) The increase to 60% seems to be because the default value of the "-XX:G1MaxNewSizePercent" option is 60%. I think it is a good situation that the heap memory graph is a saw feature, But I hope that the slope of the graph decreases, resulting in a gradual memory rise and a short gc. What should I do? ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [June 14, 2021, 9:49pm UTC](https://discuss.elastic.co/t/why-does-heap-memory-increase/275768/2 "2021-06-14T21:49:03Z")
> [@jaeho](#): > > Version: ES7.10.2 Please upgrade, the latest is 7.13 and there's always improvements being made around this topic. > [@jaeho](#): > > - Number of Shards: 4, > - Number of Replicas: 1 > - The number of indexed documents is about 20,000. > - 1 request per 1 second. > - 20,000 doucuments are updated only at 5am. (by batch) > - store.size: 57mb You really need only 1 shard and 1 replica for this dataset. If you want the data on all nodes, then increase the replica count, not the primary shard count. > [@jaeho](#): > > What should I do? Nothing, there's nothing here that suggests you have any problems and Elasticsearch and the JVM appear to be running as expected. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 12, 2021, 9:49pm UTC](https://discuss.elastic.co/t/why-does-heap-memory-increase/275768/3 "2021-07-12T21:49:24Z")
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