mbutrovich commented on code in PR #1175: URL: https://github.com/apache/datafusion-comet/pull/1175#discussion_r1890341254
########## docs/source/user-guide/metrics.md: ########## @@ -0,0 +1,62 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Comet Metrics + +## Spark SQL Metrics + +Set `spark.comet.metrics.detailed=true` to see all available Comet metrics. + +### CometScanExec + +| Metric | Description | +| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | +| `scan time` | Total time to scan a Parquet file. This is not comparable to the same metric in Spark because Comet's scan metric is more accurate. Although both Comet and Spark measure the time in nanoseconds, Spark rounds this time to the nearest millisecond per batch and Comet does not. | + +### Exchange + +Comet adds some additional metrics: + +| Metric | Description | +| ------------------------------- | ----------------------------------------------------------------------------------------- | +| `encoding and compression time` | Time to encode batches in IPC format and compress using ZSTD. | +| `native shuffle time` | Total time spent in native shuffle writer, excluding the execution time of the input plan | + +## Native Metrics + +Setting `spark.comet.explain.native.enabled=true` will cause native plans to be logged in each executor. Metrics are +logged for each native plan (and there is one plan per task, so this is very verbose). + +Here is a guide to some of the native metrics. + +### ScanExec + +| Metric | Description | +| ----------------- | --------------------------------------------------------------------------------------------------- | +| `elapsed_compute` | Total time spent in this operator, fetching batches from a JVM iterator. | +| `jvm_fetch_time` | Time spent in the JVM fetching input batches to be read by this `ScanExec` instance. | +| `arrow_ffi_time` | Time spent using Arrow FFI to create Arrow batches from the memory addresses returned from the JVM. | + +### ShuffleWriterExec + +| Metric | Description | +| ----------------- | ------------------------------------------------------------- | +| `elapsed_compute` | Total time excluding any child operators. | +| `ipc_time` | Time to encode batches in IPC format and compress using ZSTD. | Review Comment: Should we add `mempool_time` and `report_time`? ########## docs/source/user-guide/metrics.md: ########## @@ -0,0 +1,62 @@ +<!--- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Comet Metrics + +## Spark SQL Metrics + +Set `spark.comet.metrics.detailed=true` to see all available Comet metrics. + +### CometScanExec + +| Metric | Description | +| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | +| `scan time` | Total time to scan a Parquet file. This is not comparable to the same metric in Spark because Comet's scan metric is more accurate. Although both Comet and Spark measure the time in nanoseconds, Spark rounds this time to the nearest millisecond per batch and Comet does not. | + +### Exchange + +Comet adds some additional metrics: + +| Metric | Description | +| ------------------------------- | ----------------------------------------------------------------------------------------- | +| `encoding and compression time` | Time to encode batches in IPC format and compress using ZSTD. | +| `native shuffle time` | Total time spent in native shuffle writer, excluding the execution time of the input plan | + +## Native Metrics + +Setting `spark.comet.explain.native.enabled=true` will cause native plans to be logged in each executor. Metrics are +logged for each native plan (and there is one plan per task, so this is very verbose). + +Here is a guide to some of the native metrics. + +### ScanExec + +| Metric | Description | +| ----------------- | --------------------------------------------------------------------------------------------------- | +| `elapsed_compute` | Total time spent in this operator, fetching batches from a JVM iterator. | +| `jvm_fetch_time` | Time spent in the JVM fetching input batches to be read by this `ScanExec` instance. | +| `arrow_ffi_time` | Time spent using Arrow FFI to create Arrow batches from the memory addresses returned from the JVM. | + +### ShuffleWriterExec + +| Metric | Description | +| ----------------- | ------------------------------------------------------------- | +| `elapsed_compute` | Total time excluding any child operators. | +| `ipc_time` | Time to encode batches in IPC format and compress using ZSTD. | Review Comment: Should we add `mempool_time` and `repart_time`? -- This is an automated message from the Apache Git Service. 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