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| author | Davies Liu <davies@databricks.com> | 2015-11-19 17:14:10 -0800 |
|---|---|---|
| committer | Reynold Xin <rxin@databricks.com> | 2015-11-19 17:14:10 -0800 |
| commit | ee21407747fb00db2f26d1119446ccbb20c19232 (patch) | |
| tree | 60efa669e9da9e278d16484725d5eaa5ffd7b3ad /mllib | |
| parent | b2cecb80ece59a1c086d4ae7aeebef445a4e7299 (diff) | |
| download | spark-ee21407747fb00db2f26d1119446ccbb20c19232.tar.gz spark-ee21407747fb00db2f26d1119446ccbb20c19232.tar.bz2 spark-ee21407747fb00db2f26d1119446ccbb20c19232.zip | |
[SPARK-11864][SQL] Improve performance of max/min
This PR has the following optimization:
1) The greatest/least already does the null-check, so the `If` and `IsNull` are not necessary.
2) In greatest/least, it should initialize the result using the first child (removing one block).
3) For primitive types, the generated greater expression is too complicated (`a > b ? 1 : (a < b) ? -1 : 0) > 0`), should be as simple as `a > b`
Combine these optimization, this could improve the performance of `ss_max` query by 30%.
Author: Davies Liu <davies@databricks.com>
Closes #9846 from davies/improve_max.
Diffstat (limited to 'mllib')
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