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Taewoo Kim <wangsaeu@yahoo.com>
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on 04 Jan 17
ASTERIXDB-1556, ASTERIXDB-1733: Hash Group By and Hash Join conform to the memory budget
- External Hash Group By and Hash Join now conform… Show more
ASTERIXDB-1556, ASTERIXDB-1733: Hash Group By and Hash Join conform to the memory budget

- External Hash Group By and Hash Join now conform to the memory budget (compiler.groupmemory and compiler.joinmemory)

- For Optimzed Hybrid Hash Join, we calculate the expected hash table size when the build phase is done and

  try to spill one or more partitions if the freespace can't afford the hash table size.

- For External Hash Group By, the number of hash entries (hash table size) is calculated based on

  an estimation of the aggregated tuple size and possible hash values for the given field size in that tuple.

- Garbage Collection feature has been added to SerializableHashTable. For external hash group-by,

  whenever we spill a data partition to the disk, we also check the ratio of garbage in the hash table.

  If it's greater than the given threshold, we conduct a GC on Hash Table.

Change-Id: I2b323e9a2141b4c1dd1652a360d2d9354d3bc3f5

Reviewed-on: https://asterix-gerrit.ics.uci.edu/1056

Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

BAD: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

Reviewed-by: Yingyi Bu <buyingyi@gmail.com>

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