andygrove commented on code in PR #1173: URL: https://github.com/apache/datafusion-comet/pull/1173#discussion_r1887741387
########## docs/source/user-guide/metrics.md: ########## @@ -0,0 +1,63 @@ +<!--- +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 + +`CometScanExec` uses nanoseconds for total scan time. Spark also measures scan time in nanoseconds but converts to Review Comment: Spark converts nanos to millis on each batch: ```scala override def hasNext: Boolean = { // The `FileScanRDD` returns an iterator which scans the file during the `hasNext` call. val startNs = System.nanoTime() val res = batches.hasNext scanTime += NANOSECONDS.toMillis(System.nanoTime() - startNs) res } ``` We just use the nano time: ``` override def hasNext: Boolean = { // The `FileScanRDD` returns an iterator which scans the file during the `hasNext` call. val startNs = System.nanoTime() val res = batches.hasNext scanTime += System.nanoTime() - startNs res } ``` It actually makes a large difference to the time reported in some cases -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
