This topic describes a stress test performed on Alibaba Cloud Elasticsearch V5.5.3 clusters that have different specifications and reside in the China (Hangzhou) region. The test is performed by using a Rally script that is provided by open source Elasticsearch for benchmarking Elasticsearch clusters. This topic also describes the metrics and the operation parameter used in the stress test.
Overview
Rally is a stress test tool provided by open source Elasticsearch. In this example, Rally is used to perform a stress test on the Alibaba Cloud Elasticsearch clusters that have different specifications.
Metrics used in the stress test
Before you perform a stress test on an Elasticsearch cluster, you can refer to the following table to understand the related metrics.
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 a stress test by using Rally.
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 average 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 average 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 average 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 average 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 average 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 average 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 the documents in indexes of all primary shards. | |
Heap used for terms | The size of heap memory occupied by terms factors of indexes of all primary shards. | |
Heap used for norms | The size of heap memory occupied by norms factors of indexes of all primary shards. | |
Heap used for points | The size of heap memory occupied by points of indexes of all primary shards. | |
Heap used for stored fields | The size of heap memory occupied by fields in indexes of all primary shards. | |
Segment count | The number of segments of indexes 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 average QPS for each task. | |
Max Throughput | The maximum QPS for each task. | |
Metrics related to latency | 50th percentile latency | The maximum latency for the fastest 50% of all requests. |
90th percentile latency | The maximum latency for the fastest 90% of all requests. | |
99.9th percentile latency | The maximum latency for the fastest 99.9% of all requests. | |
100th percentile latency | The maximum 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. |
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.
Description of the operation parameter
You can refer to the values of the operation parameter that are listed in the following table to analyze data collected based on metrics such as throughput, latency, service time, and error rate.
Value | 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. |