Hello David Rorke, Tim Armstrong, Csaba Ringhofer, Impala Public Jenkins,

I'd like you to reexamine a change. Please visit


to look at the new patch set (#14).

Change subject: IMPALA-6692: Trigger sort node run before hitting memory limit.

IMPALA-6692: Trigger sort node run before hitting memory limit.

Sorter node works by adding row batches to a sort run. After all
batches added to current unsorted run or memory limit is hit, sorter
will immediately start the run. If the latter case happen, sorter will
spill the sorted run to disk after sort complete, create new unsorted
run object, and continue add the next row batches, and so on.

This algorithm try to fit as much rows into memory before start
sorting. However, in the case of partitioned sort with large number of
row batches, fitting too much rows into memory will cause the sort to
be slow and block the sorter node for a long time before it can
release some memory and continue accepting the next row batch from
exchange node. One slow sorter node can block exchange node from
sending row batches to other sorter node that is free.

This patch speedup the decision to start the sort without waiting it
to hit memory limit first by capping the intermediary quicksort run to
lower memory limit, determined by query option 'sort_run_bytes_limit'.
If the total used reservation of quicksort has exceed
sort_run_bytes_limit, current unsorted_run_ will be wrapped up,
sorted, and then spilled. Thus, overlapping the next sort run with
spill from previous sort run.

To reduce regression for cases where total input size of sort node
might be fully fitted into available memory, sort_run_bytes_limit will
not be enforced for the first sort run. However, it will stay limited
by sort_run_bytes_limit if planner estimates hint that spill is
inevitably will happen.

We also add new summary counter 'AddBatchTime' to get summary of how
much time spent in Sorter::AddBatch. Max of 'AddBatchTime' indicate
the longest time spent in Sorter::AddBatch, presumably busy doing
intermediary sort.

- Add new e2e test TestQueryFullSort::test_multiple_sort_run_bytes_limits
- Run core tests
- Run data loading of 3 largest TPC-DS facts table of 300GB scale into
  real cluster using 5 backends, and 4GB mem_limit.
  sort_run_bytes_limit is varied between unspecified (not limited) vs
  512 MB. The performance result is summarized in the following table.

|  Insert table |  #Rows  |      Avg     |       no limit        |      512 MB 
limit       |
|               |         | SortDataSize 
|               |         |   per Node   |  Query |      Max     |  Query  |    
  Max      |
|               |         |              |  Time  | AddBatchTime |   Time  |  
AddBatchTime |
| store_sales   | 864.00M |     15.29 GB | 30m18s |     53s311ms |     20m |    
   5s634ms |
| catalog_sales | 431.97M |     11.34 GB | 23m24s |     31s212ms |  15m27s |    
   3s603ms |
| web_sales     | 216.01M |      5.67 GB |  8m16s |     29s250ms |   6m41s |    
   3s856ms |

Change-Id: I2a0ba7c4bae4f1d300d4d9d7f594f63ced06a240
M be/src/exec/sort-node.cc
M be/src/exec/sort-node.h
M be/src/runtime/coordinator-backend-state.cc
M be/src/runtime/query-state.cc
M be/src/runtime/query-state.h
M be/src/runtime/sorter.cc
M be/src/runtime/sorter.h
M be/src/service/query-options-test.cc
M be/src/service/query-options.cc
M be/src/service/query-options.h
M common/thrift/ImpalaInternalService.thrift
M common/thrift/ImpalaService.thrift
M common/thrift/PlanNodes.thrift
M fe/src/main/java/org/apache/impala/planner/SortNode.java
M tests/query_test/test_sort.py
15 files changed, 225 insertions(+), 11 deletions(-)

  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/63/15963/14
To view, visit http://gerrit.cloudera.org:8080/15963
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I2a0ba7c4bae4f1d300d4d9d7f594f63ced06a240
Gerrit-Change-Number: 15963
Gerrit-PatchSet: 14
Gerrit-Owner: Riza Suminto <riza.sumi...@cloudera.com>
Gerrit-Reviewer: Csaba Ringhofer <csringho...@cloudera.com>
Gerrit-Reviewer: David Rorke <dro...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Riza Suminto <riza.sumi...@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com>

Reply via email to