Reduce number of calls to fetch table schema from HMS #1794
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rdblue
approved these changes
Nov 20, 2020
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Looks good to me, but I'll wait for other reviewers with more knowledge of Hive to weigh in. Thanks, @marton-bod!
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This is not guaranteed to work in future versions of Hive but definitely will not hurt and helps the performance with the current versions. |
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We can reduce the number of HMS calls by caching the table schema in the table properties during query execution.
In
HiveIcebergSerDe.initialize(), this results in skipping the HMS calls in all Tez workers as well as during the query optimisation steps. In thetestJoinTable()unit test, this results in a 40% reduction in schema-related HMS calls (10 -> 6).@shardulm94 @pvary - could you please take a look when you get the chance? Thanks!