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commit 89362ea869e80658b315a517ada7de1bdfc5d180
Author: Tim Armstrong <tarmstr...@cloudera.com>
AuthorDate: Mon Jan 28 23:38:08 2019 -0800
IMPALA-8134: update docs for CGroup mem limits
Change-Id: I07f309f1a4475fa3f96448178575888f4fd4e1bd
Reviewed-on: http://gerrit.cloudera.org:8080/12293
Reviewed-by: Tim Armstrong <tarmstr...@cloudera.com>
Tested-by: Tim Armstrong <tarmstr...@cloudera.com>
---
docs/topics/impala_mem_limit.xml | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/docs/topics/impala_mem_limit.xml b/docs/topics/impala_mem_limit.xml
index 5e0ca65..395ab0b 100644
--- a/docs/topics/impala_mem_limit.xml
+++ b/docs/topics/impala_mem_limit.xml
@@ -45,8 +45,16 @@ under the License.
<p rev="">
There are two levels of memory limit for Impala.
The <codeph>-mem_limit</codeph> startup option sets an overall limit for
the <cmdname>impalad</cmdname> process
- (which handles multiple queries concurrently).
- That limit is typically expressed in terms of a percentage of the RAM
available on the host, such as <codeph>-mem_limit=70%</codeph>.
+ (which handles multiple queries concurrently). That process memory limit
can be expressed either as a percentage
+ of RAM available to the process such as <codeph>-mem_limit=70%</codeph>
or as a fixed
+ amount of memory, such as <codeph>100gb</codeph>. The memory available
to the process is based on the host's
+ physical memory and, since Impala 3.2, memory limits from Linux Control
Groups. E.g. if an
+ <cmdname>impalad</cmdname> process is running in a Docker container on a
host with 100GB of memory, the memory
+ available is 100GB or the Docker container's memory limit, whichever is
less.
+ </p>
+
+
+ <p rev="">
The <codeph>MEM_LIMIT</codeph> query option, which you set through
<cmdname>impala-shell</cmdname>
or the <codeph>SET</codeph> statement in a JDBC or ODBC application,
applies to each individual query.
The <codeph>MEM_LIMIT</codeph> query option is usually expressed as a
fixed size such as <codeph>10gb</codeph>,
