parthchandra commented on code in PR #999: URL: https://github.com/apache/parquet-mr/pull/999#discussion_r993981829
########## parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetFileReader.java: ########## @@ -1093,10 +1099,38 @@ private ColumnChunkPageReadStore internalReadFilteredRowGroup(BlockMetaData bloc } } } - // actually read all the chunks + // Vectored IO up. + + List<FileRange> ranges = new ArrayList<>(); for (ConsecutivePartList consecutiveChunks : allParts) { - consecutiveChunks.readAll(f, builder); + ranges.add(FileRange.createFileRange(consecutiveChunks.offset, (int) consecutiveChunks.length)); + } + LOG.warn("Doing vectored IO for ranges {}", ranges); + f.readVectored(ranges, ByteBuffer::allocate); Review Comment: So if I have something like this - `range 1, delta 1, range2` I will give you two ranges, `range1`, and `range2` separated by a gap of `delta1` bytes. If `delta1` is small enough, you will merge `range1` and `range2` and do a single scan. If `range1` and `range2` are very large so that the resulting range is even larger, do you still do a single scan, or do you split the large range into smaller ranges and tradeoff some seek cost for increased parallelism? -- 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