Only equality joins, outer joins, and left semi joins are supported in Hive.Hive does not support join conditions that are not equality conditions as it is very difficult to express such conditions as a map/reduce job.Also, more than two tables can be joined in Hive. Hive 暂时只支持等值连...
Our target scenario is big-data systems, e.g., SCOPE [47], Spark[39, 88], Hive [84], F1 [80] or Pig [70] clusters that run SQL-like queries over large datasets; recent reports estimate over a million servers in such clusters [1]. Big-data systems already maintain data statistics...
Compared with NFA-based MATCH_RECOGNIZE implementations on a benchmark of 1,800 query instances spanning over 6 patterns and 3 pattern definitions based on existing datasets [34], our ap- proach hits median speed-ups of 5.4× on Trino (v373 with ORC files on Hive), 57.5× on SQL Server...
4GB of data, in a table with 2 bucketized partitions) NEVER even complets a single mapper. Of course, I'd appreciate any help that can be provided. I'm impressed with Hive so far and hope to use it replace an RDBMS for "real" ETL, but that's only possible if I can get this sor...