Sahil Takiar created IMPALA-8544: ------------------------------------ Summary: Expose additional S3A / S3Guard metrics Key: IMPALA-8544 URL: https://issues.apache.org/jira/browse/IMPALA-8544 Project: IMPALA Issue Type: Improvement Components: Backend Reporter: Sahil Takiar Assignee: Sahil Takiar
S3A / S3Guard internally collects several useful metrics that we should consider exposing to Impala users. The full list of statistics can be found in {{o.a.h.fs.s3a.Statistic}}. The stats include: the number of S3 operations performed (put, get, etc.), invocation counts for various {{FileSystem}} methods, stream statistics (bytes read, written, etc.), etc. Some interesting stats that stand out: * "stream_aborted": "Count of times the TCP stream was aborted" - the number of TCP connection aborts, a high value would indicate performance issues * "stream_read_exceptions" : "Number of exceptions invoked on input streams" - incremented whenever an {{IOException}} is caught while reading (these exception don't always get propagated to Impala because they trigger a retry) * "store_io_throttled": "Requests throttled and retried" - looks like it tracks the number of times the fs retries an operation because the original request hit a throttling exception * "s3guard_metadatastore_retry": "S3Guard metadata store retry events" - looks like it tracks the number of times the fs retries S3Guard operations * "s3guard_metadatastore_throttled" : "S3Guard metadata store throttled events" - similar to "store_io_throttled" but looks like it is specific to S3Guard We should consider how to expose these metrics via Impala logs / runtime profiles. There are a few options: * {{S3AFileSystem}} exposes {{StorageStatistics}} specific to S3A / S3Guard via the {{FileSystem#getStorageStatistics}} method; the {{S3AStorageStatistics}} seems to include all the S3A / S3Guard metrics, however, I think the stats might be aggregated globally, which would make it hard to create per-query specific metrics * {{S3AInstrumentation}} exposes all the metrics as well, and looks like it is per-fs instance, so it is not aggregated globally; {{S3AInstrumentation}} extends {{o.a.h.metrics2.MetricsSource}} so perhaps it is exposed via some API (haven't looked into this yet) * {{S3AInputStream#toString}} dumps the statistics from {{o.a.h.fs.s3a.S3AInstrumentation.InputStreamStatistics}} and {{S3AFileSystem#toString}} dumps them all as well * {{S3AFileSystem}} updates the stats in {{o.a.h.fs.Statistics.StatisticsData}} as well (e.g. bytesRead, bytesWritten, etc.) Impala has a {{hdfs-fs-cache}} as well, so {{hdfsFs}} objects get shared across threads. -- This message was sent by Atlassian JIRA (v7.6.3#76005)