Zoltan Martonka has uploaded this change for review. ( 
http://gerrit.cloudera.org:8080/24731


Change subject: WIP KUDU-2874 Test ordered scan memory usage with large cells.
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WIP KUDU-2874 Test ordered scan memory usage with large cells.

Currently sorted scans has a burned in 1024 size buffer.
With 1 MB of cells this can cause large, untracked memory usage.

This test does the following:
+ Start a tserver with one tablet.
+ Disable compaction for worst case result (compaction falls behind).
+ Write rows with 1 MB cells into a tablet.
+ Optionally disable flushing to disk at a point, so memory usage
remains large.
+ Start 10 parallel ordered full scans. They are started one-by-one with a
  gap between them, so they probably request other parts of the data at
  the same time.
+ Compare tmalloc reported memory usage with the trackers.

tmalloc also counts the tests memory usage, but the "keep_unflushed"
reports 10 GB of "untracked" memory, which is a lot. 20 GB of tracked
memory is also unacceptable for a 8GB memory limit.

2 things should be addressed to fix the test:
+ Dynamically downsize batches when cells are really large.
+ Properly count memory at scans when copying values from memrowset.
  (It is counted properly when loaded from disk rowsets).

Change-Id: I75ceaebac1793c2421302f8b205ba85ad32a141a
---
M src/kudu/tserver/CMakeLists.txt
A src/kudu/tserver/upsert_ordered_scan-test.cc
2 files changed, 566 insertions(+), 0 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/31/24731/1
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I75ceaebac1793c2421302f8b205ba85ad32a141a
Gerrit-Change-Number: 24731
Gerrit-PatchSet: 1
Gerrit-Owner: Zoltan Martonka <[email protected]>

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