Misha Dmitriev has uploaded this change for review. ( 
http://gerrit.cloudera.org:8080/10982


Change subject: IMPALA-7219. 7.5% of Catalog Server heap wasted by empty 
HashMaps and ArrayLists
......................................................................

IMPALA-7219. 7.5% of Catalog Server heap wasted by empty HashMaps and ArrayLists

This change switches initialization of HashMaps in IncompleteTable.colsByName_ 
and
StructType.fieldMap_ from eager to lazy. In this way, we avoid wasting memory
when HashMaps stay empty (even an empty HashMap uses at least 48 bytes in the 
heap).
This optimization becomes really relevant when a catalog server loads a very 
large
number (millions) of tables.

Change-Id: If9c75f65ecb3ba3f2c739fa483a84dc052f471c6
---
M fe/src/main/java/org/apache/impala/catalog/StructType.java
M fe/src/main/java/org/apache/impala/catalog/Table.java
2 files changed, 35 insertions(+), 8 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/82/10982/2
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: If9c75f65ecb3ba3f2c739fa483a84dc052f471c6
Gerrit-Change-Number: 10982
Gerrit-PatchSet: 2
Gerrit-Owner: Misha Dmitriev <[email protected]>
Gerrit-Reviewer: Todd Lipcon <[email protected]>
Gerrit-Reviewer: Vuk Ercegovac <[email protected]>

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