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Posted to commits@impala.apache.org by jo...@apache.org on 2019/02/16 01:20:16 UTC
[impala] 01/04: [DOCS] Copy edit a part of impala_timestamp.xml
This is an automated email from the ASF dual-hosted git repository.
joemcdonnell pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/impala.git
commit 4f5096570cab1b4b76b4345f9f69dc23baa04aad
Author: Alex Rodoni <ar...@cloudera.com>
AuthorDate: Fri Feb 15 13:02:48 2019 -0800
[DOCS] Copy edit a part of impala_timestamp.xml
Change-Id: I140ca64692982c7409653e01e9d089a730e5e787
Reviewed-on: http://gerrit.cloudera.org:8080/12502
Reviewed-by: Alex Rodoni <ar...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>
---
docs/topics/impala_timestamp.xml | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/docs/topics/impala_timestamp.xml b/docs/topics/impala_timestamp.xml
index 15dca34..87d1c66 100644
--- a/docs/topics/impala_timestamp.xml
+++ b/docs/topics/impala_timestamp.xml
@@ -219,18 +219,21 @@ DATE_ADD (<varname>timestamp</varname>, INTERVAL <varname>interval</varname> <va
</li>
</ul>
</p><p> When the
- <codeph>-convert_legacy_hive_parquet_utc_timestamps</codeph> setting
- is enabled, Impala recognizes the Parquet data files written by Hive,
- and applies the same UTC-to-local-timezone conversion logic during the
- query as Hive does. </p><p>In <keyword keyref="impala30"/> and lower,
- this option had severe impact on multi-threaded performance. The new
+ <codeph>‑‑convert_legacy_hive_parquet_utc_timestamps</codeph>
+ setting is enabled, Impala recognizes the Parquet data files written
+ by Hive, and applies the same UTC-to-local-timezone conversion logic
+ during the query as Hive does. </p><p>In <keyword keyref="impala30"/>
+ and lower, the
+ <codeph>‑‑convert_legacy_hive_parquet_utc_timestamps</codeph>
+ setting had a severe impact on multi-threaded performance. The new
time zone implementation in <keyword keyref="impala31"/> eliminated
most of the performance overhead and made Impala scale well to
multiple threads. Although
- <codeph>-convert_legacy_hive_parquet_utc_timestamps</codeph> is
- turned off by default for this performance reason, where practical
- turn it on when processing <codeph>TIMESTAMP</codeph> columns in
- Parquet files written by Hive, to avoid unexpected behavior. </p></li>
+ <codeph>‑‑convert_legacy_hive_parquet_utc_timestamps</codeph> is
+ turned off by default for a performance reason, to avoid unexpected
+ behavior, turn on the option when processing
+ <codeph>TIMESTAMP</codeph> columns in Parquet files written by
+ Hive.</p></li>
</ul>
<p>