kazuyukitanimura commented on a change in pull request #34611: URL: https://github.com/apache/spark/pull/34611#discussion_r754843844
########## File path: sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/VectorizedPlainValuesReader.java ########## @@ -53,19 +53,50 @@ public void skip() { throw new UnsupportedOperationException(); } + private void updateCurrentByte() { + try { + currentByte = (byte) in.read(); + } catch (IOException e) { + throw new ParquetDecodingException("Failed to read a byte", e); + } + } + @Override public final void readBooleans(int total, WritableColumnVector c, int rowId) { - // TODO: properly vectorize this - for (int i = 0; i < total; i++) { - c.putBoolean(rowId + i, readBoolean()); + int i = 0; + if (bitOffset > 0) { + i = Math.min(8 - bitOffset, total); + c.putBooleans(rowId, i, currentByte, bitOffset); + bitOffset = (bitOffset + i) & 7; + } + for (; i + 7 < total; i += 8) { + updateCurrentByte(); + c.putBooleans(rowId + i, currentByte); + } + if (i < total) { + updateCurrentByte(); + bitOffset = total - i; + c.putBooleans(rowId + i, bitOffset, currentByte, 0); } } @Override public final void skipBooleans(int total) { - // TODO: properly vectorize this - for (int i = 0; i < total; i++) { - readBoolean(); + // Using >>3 instead of /8 below. The difference is important when (total-(8-bitOffset))<0. + // E.g. (-1)>>3=(-1) vs. (-1)/8=0. The latter incorrectly enters the if(numBytesToSkip>=0){. Review comment: Let's say `total=8`, `bitOffset=1`, then there are `(8-bitOffset)=7` bits to skip in the `currentByte`. Now there is still 1 more bit to skip as `total=8`. So `updateCurrentByte()` needs to be called to update the `currentByte` and `bitOffset` will be again `1`. In the future, the rest of the 7bits may be read from the updated `currentByte`. For that reason, we need to go into the if statement when `numBytesToSkip = (8 - (8 - 1)) >> 3 = 1>>3 = 0`. The following is a few-lines longer but equivalent condition. ``` if (numBytesToSkip > 0) { try { in.skipFully(numBytesToSkip); } catch (IOException e) {...} } if (numBytesToSkip >= 0 && bitOffset > 0) { updateCurrentByte(); } ``` The scenario is tested at https://github.com/apache/spark/pull/34611/files#diff-b84cbbb2eadfa9d267b9ab8be2e6be579f28c1813623785c9e667a864f7960e1R194 -- 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: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org