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Subject [4/5] accumulo git commit: ACCUMULO-3124 Document size and number of user-provided properties
Date Fri, 01 May 2015 05:14:56 GMT
ACCUMULO-3124 Document size and number of user-provided properties

Include warnings for both custom "tags" and iterator options


Branch: refs/heads/1.7
Commit: fae7a8224e5f259881ca744ce1aaeb062276127a
Parents: 2b48d1c
Author: Josh Elser <>
Authored: Fri May 1 00:12:22 2015 -0400
Committer: Josh Elser <>
Committed: Fri May 1 00:12:22 2015 -0400

 .../org/apache/accumulo/core/conf/config-header.txt         | 9 +++++++++
 docs/src/main/asciidoc/chapters/administration.txt          | 7 +++++++
 2 files changed, 16 insertions(+)
diff --git a/core/src/main/resources/org/apache/accumulo/core/conf/config-header.txt b/core/src/main/resources/org/apache/accumulo/core/conf/config-header.txt
index d278882..be1958f 100644
--- a/core/src/main/resources/org/apache/accumulo/core/conf/config-header.txt
+++ b/core/src/main/resources/org/apache/accumulo/core/conf/config-header.txt
@@ -52,6 +52,15 @@ All properties have a default value in the source code.  This value has
the lowe
 While the default value is usually optimal, there are cases where a change can increase query
and ingest performance.
+==== ZooKeeper Property Considerations
+Any properties that are stored in ZooKeeper should consider the limitations of ZooKeeper
itself with respect to the
+number of nodes and the size of the node data. Custom table properties and options for Iterators
configured on tables
+are two areas in which there aren't any failsafes built into the API that can prevent the
user from making this mistake.
+While these properties have the ability to add some much needed dynamic configuration tools,
use cases which might fall
+into these warnings should be reconsidered.
 === Configuration in the Shell
 The `config` command in the shell allows you to view the current system configuration.  You
can also use the `-t` option to view a table's configuration as below:
diff --git a/docs/src/main/asciidoc/chapters/administration.txt b/docs/src/main/asciidoc/chapters/administration.txt
index 520a07c..857d948 100644
--- a/docs/src/main/asciidoc/chapters/administration.txt
+++ b/docs/src/main/asciidoc/chapters/administration.txt
@@ -296,6 +296,13 @@ applications to set application-level metadata about a table.  These
tags can be
 anything from a table description, administrator notes, date created, etc.
 This is done by naming and setting a property with a prefix +table.custom.*+.
+Currently, table properties are stored in ZooKeeper. This means that the number
+and size of custom properties should be restricted on the order of 10's of properties
+at most without any properties exceeding 1MB in size. ZooKeeper's performance can be
+very sensitive to an excessive number of nodes and the sizes of the nodes. Applications
+which leverage the user of custom properties should take these warnings into
+consideration. There is no enforcement of these warnings via the API.
 === Initialization
 Accumulo must be initialized to create the structures it uses internally to locate

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