Ruslan Dautkhanov created SPARK-21657: -----------------------------------------
Summary: Spark has exponential time complexity to explode(array of structs) Key: SPARK-21657 URL: https://issues.apache.org/jira/browse/SPARK-21657 Project: Spark Issue Type: Bug Components: Spark Core, SQL Affects Versions: 2.2.0, 2.1.1, 2.1.0, 2.0.0 Reporter: Ruslan Dautkhanov Priority: Critical It can take up to half a day to explode a modest-sizes nested collection (0.5m). On a recent Xeon processors. See attached pyspark script that reproduces this problem. {code} cached_df = sqlc.sql('select individ, hholdid, explode(amft) from ' + table_name).cache() print sqlc.count() {code} This script generate a number of tables, with the same total number of records across all nested collection (see `scaling` variable in loops). `scaling` variable scales up how many nested elements in each record, but by the same factor scales down number of records in the table. So total number of records stays the same. Time grows exponentially (notice log-10 vertical axis scale). -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org