andygrove commented on code in PR #349: URL: https://github.com/apache/datafusion-comet/pull/349#discussion_r1583877737
########## docs/source/user-guide/configs.md: ########## @@ -0,0 +1,58 @@ +<!--- +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 Configuration Settings + +Comet provides the following configuration settings. + +| Config | Description | Default Value | +|--------|-------------|---------------| +| spark.comet.ansi.enabled | Comet does not respect ANSI mode in most cases and by default will not accelerate queries when ansi mode is enabled. Enable this setting to test Comet's experimental support for ANSI mode. This should not be used in production. | false | +| spark.comet.batchSize | The columnar batch size, i.e., the maximum number of rows that a batch can contain. | 8192 | +| spark.comet.cast.stringToTimestamp | Comet is not currently fully compatible with Spark when casting from String to Timestamp. | false | +| spark.comet.columnar.shuffle.async.enabled | Whether to enable asynchronous shuffle for Arrow-based shuffle. By default, this config is false. | false | +| spark.comet.columnar.shuffle.async.max.thread.num | Maximum number of threads on an executor used for Comet async columnar shuffle. By default, this config is 100. This is the upper bound of total number of shuffle threads per executor. In other words, if the number of cores * the number of shuffle threads per task `spark.comet.columnar.shuffle.async.thread.num` is larger than this config. Comet will use this config as the number of shuffle threads per executor instead. | 100 | +| spark.comet.columnar.shuffle.async.thread.num | Number of threads used for Comet async columnar shuffle per shuffle task. By default, this config is 3. Note that more threads means more memory requirement to buffer shuffle data before flushing to disk. Also, more threads may not always improve performance, and should be set based on the number of cores available. | 3 | +| spark.comet.columnar.shuffle.batch.size | Batch size when writing out sorted spill files on the native side. Note that this should not be larger than batch size (i.e., `spark.comet.batchSize`). Otherwise it will produce larger batches than expected in the native operator after shuffle. | 8192 | +| spark.comet.columnar.shuffle.enabled | Force Comet to only use columnar shuffle for CometScan and Spark regular operators. If this is enabled, Comet native shuffle will not be enabled but only Arrow shuffle. By default, this config is false. | false | +| spark.comet.columnar.shuffle.memory.factor | Fraction of Comet memory to be allocated per executor process for Comet shuffle. Comet memory size is specified by `spark.comet.memoryOverhead` or calculated by `spark.comet.memory.overhead.factor` * `spark.executor.memory`. By default, this config is 1.0. | 1.0 | +| spark.comet.columnar.shuffle.spill.threshold | Number of rows to be spilled used for Comet columnar shuffle. For every configured number of rows, a new spill file will be created. Higher value means more memory requirement to buffer shuffle data before flushing to disk. As Comet uses columnar shuffle which is columnar format, higher value usually helps to improve shuffle data compression ratio. This is internal config for testing purpose or advanced tuning. By default, this config is Int.Max. | 2147483647 | Review Comment: Great point. Let me fix that. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
