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Elasticsearch:Metrics and task parameters for performance stress testing

Last Updated:Dec 22, 2023

Rally is used to perform stress testing on Alibaba Cloud Elasticsearch clusters of different specifications and versions. This topic describes the main metrics and task parameters involved in the stress testing.

Background information

Rally is a stress testing tool provided by open source Elasticsearch. For more information about stress testing and how to use Rally, visit the official website of Rally.

Main metrics involved in stress testing

The following table describes only some important metrics for your reference. You can infer the meanings of other metrics based on the metrics described in the following table. For more information about other metrics, see the documentation for metrics for stress testing performed by using Rally.

Note
  • The latency indicates the period of time from the point in time when a request is submitted to the point in time when a complete response is received. The latency includes the waiting period before Elasticsearch starts to process the request.

  • The service time indicates the period of time from the point in time when a request starts to be processed to the point in time when a response is received.

  • The error rate indicates the rate of responses that contain errors to all responses.

Metric type

Metric name

Description

Metrics related to indexing of primary shards

Cumulative indexing time of primary shards

The cumulative time used for indexing of all primary shards.

Note

The time is not wall-clock time. It is the sum of the CPU time consumed by multiple threads used for indexing. For example, M threads are used for indexing, and each thread runs for N minutes. In this case, the time collected by this metric is calculated by using the following formula: M × N (unit: minutes).

Min cumulative indexing time across primary shards

The minimum cumulative time used for indexing across primary shards.

Median cumulative indexing time across primary shards

The median cumulative time used for indexing across primary shards.

Max cumulative indexing time across primary shards

The maximum cumulative time used for indexing across primary shards.

Cumulative indexing throttle time of primary shards

The cumulative time that indexing of all primary shards is throttled.

Note

The time is not wall-clock time. It is the sum of the CPU time consumed by multiple threads used for indexing when indexing is throttled.

Min cumulative indexing throttle time across primary shards

The minimum cumulative time that indexing across primary shards is throttled.

Median cumulative indexing throttle time across primary shards

The median cumulative time that indexing across primary shards is throttled.

Max cumulative indexing throttle time across primary shards

The maximum cumulative time that indexing across primary shards is throttled.

Cumulative merge time of primary shards

The cumulative runtime used for merge operations for primary shards. The time also indicates the sum of the CPU time consumed by all threads.

Cumulative merge count of primary shards

The cumulative number of merges of primary shards.

Note

Some primary shards may not be merged.

Min cumulative merge time across primary shards

The minimum cumulative time used for merge operations across primary shards.

Median cumulative merge time across primary shards

The median cumulative time used for merge operations across primary shards.

Max cumulative merge time across primary shards

The maximum cumulative time used for merge operations across primary shards.

Cumulative merge throttle time of primary shards

The cumulative time that merge operations for primary shards are throttled. The time also indicates the sum of the CPU time consumed by all threads.

Min cumulative merge throttle time across primary shards

The minimum cumulative time that merge operations across primary shards are throttled. The time also indicates the sum of the CPU time consumed by all threads.

Median cumulative merge throttle time across primary shards

The median cumulative time that merge operations across primary shards are throttled. The time also indicates the sum of the CPU time consumed by all threads.

Max cumulative merge throttle time across primary shards

The maximum cumulative time that merge operations across primary shards are throttled. The time also indicates the sum of the CPU time consumed by all threads.

Cumulative refresh time of primary shards

The cumulative time used for index refresh of primary shards. The time also indicates the CPU time consumed by all threads.

Cumulative refresh count of primary shards

The cumulative number of refreshes of primary shards.

Min cumulative refresh time across primary shards

The minimum cumulative time used for index refresh across primary shards.

Median cumulative refresh time across primary shards

The median cumulative time used for index refresh across primary shards.

Max cumulative refresh time across primary shards

The maximum cumulative time used for index refresh across primary shards.

Cumulative flush time of primary shards

The cumulative time used for flushing transactional data of indexing of primary shards from the cache to a disk. The time also indicates the sum of the CPU time consumed by all threads.

Cumulative flush count of primary shards

The cumulative number of flushes for transactional data of indexing of primary shards from the cache to a disk.

Min cumulative flush time across primary shards

The minimum cumulative time used for flushing transactional data of indexing across primary shards from the cache to a disk. The time also indicates the sum of the CPU time consumed by all threads.

Median cumulative flush time across primary shards

The median cumulative time used for flushing transactional data of indexing across primary shards from the cache to a disk. The time also indicates the sum of the CPU time consumed by all threads.

Max cumulative flush time across primary shards

The maximum cumulative time used for flushing transactional data of indexing across primary shards from the cache to a disk. The time also indicates the sum of the CPU time consumed by all threads.

Store size

The size of data stored in indexes. The size does not include the size of translogs and that of data stored in replica shards.

Translog size

The size of translogs.

Heap used for segments

The size of heap memory occupied by the segments of all primary shards.

Heap used for doc values

The size of heap memory occupied by documents in all primary shards.

Heap used for terms

The size of heap memory occupied by terms factors of all primary shards.

Heap used for norms

The size of heap memory occupied by norms factors of all primary shards.

Heap used for points

The size of heap memory occupied by points of all primary shards.

Heap used for stored fields

The size of heap memory occupied by fields in all primary shards.

Segment count

The number of segments of all primary shards.

Metrics related to garbage collectors

Total Young Gen GC

The total runtime of the young-generation garbage collector in the entire cluster.

Total Old Gen GC

The total runtime of the old-generation garbage collector in the entire cluster.

Metrics related to throughput

Min Throughput

The minimum queries per second (QPS) for each task.

Median Throughput

The median QPS for each task.

Max Throughput

The maximum QPS for each task.

Metrics related to latency

50th percentile latency

The latency for the fastest 50% of all requests.

90th percentile latency

The latency for the fastest 90% of all requests.

99.9th percentile latency

The latency for the fastest 99.9% of all requests.

100th percentile latency

The latency for all requests.

Metrics related to service time

50th percentile service time

The service time for the fastest 50% of all requests.

90th percentile service time

The service time for the fastest 90% of all requests.

99.9th percentile service time

The service time for the fastest 99.9% of all requests.

100th percentile service time

The service time for all requests.

Metrics related to error rates

error rate

The rate of responses that contain errors to all responses.

Task parameters involved in stress testing

You can view metrics such as throughput, latency, service time, and error rate of a cluster by task.

Operation

Description

index-append

The index creation operation.

index-stats

The status of an index.

node-stats

The status of a node.

default

The default dimension.

term

The term query.

phrase

The exact queries for phrases.

country_agg_uncached

The aggregate operation that is not cached.

country_agg_cached

The aggregate operation that is cached.

scroll

The scroll operation.

expression

The expression.

painless_static

The static script.

painless_dynamic

The dynamic script.

large_terms

The combination of multiple term queries.

large_filtered_terms

The combination of multiple filtered term queries.

large_prohibited_terms

The combination of multiple prohibited term queries.

References