sunchao commented on PR #968: URL: https://github.com/apache/parquet-mr/pull/968#issuecomment-1137568979
> and yes, updating parquet dependencies would be good, hadoop 3.3.0 should be the baseline. +1 on upgrading to 3.3.0, although currently parquet is using 2.10.1 as a provided dependency and we need to make sure it continues to work with hadoop 2.x > It may be because I was using Spark's vectorized parquet decoding which is an order or magnitude faster than parquet library's row by row decoding (see [Spark benchmarks](https://github.com/apache/spark/blob/master/sql/core/benchmarks/DataSourceReadBenchmark-results.txt)). If trino is not doing vectorized decoding (I took a very quick look and I don't think it is), I would suggest you can look into that next. All the cool kids are doing it. Presto already has a [batch reader](https://github.com/prestodb/presto/tree/master/presto-parquet/src/main/java/com/facebook/presto/parquet/batchreader) but seems the feature is not in Trino yet. The batch reader did help a lot to reduce the CPU load. See [the slides](https://github.com/prestodb/presto/wiki/files/presto-meetup-oct-2019/uber.pdf). -- 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: dev-unsubscr...@parquet.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
