hanover-fiste commented on a change in pull request #31965: URL: https://github.com/apache/spark/pull/31965#discussion_r602786516
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRelation.scala ########## @@ -118,13 +119,28 @@ private[sql] object JDBCRelation extends Logging { s"Upper bound: ${boundValueToString(upperBound)}.") upperBound - lowerBound } - // Overflow and silliness can happen if you subtract then divide. - // Here we get a little roundoff, but that's (hopefully) OK. - val stride: Long = upperBound / numPartitions - lowerBound / numPartitions + + // Overflow can happen if you subtract then divide. For example: + // (Long.MaxValue - Long.MinValue) / (numPartitions - 2). + // Also, using fixed-point decimals here to avoid possible inaccuracy from floating point. + val strideUpperCalculation = (upperBound / BigDecimal(numPartitions)) + .setScale(18, RoundingMode.HALF_EVEN) + val strideLowerCalculation = (lowerBound / BigDecimal(numPartitions)) + .setScale(18, RoundingMode.HALF_EVEN) Review comment: I'll go ahead and mark this as resolved for now. We can unresolve it if you, or someone else, have a different suggestion. -- 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. 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