ACCUMULO-3124 Document size and number of user-provided properties Include warnings for both custom "tags" and iterator options
Project: http://git-wip-us.apache.org/repos/asf/accumulo/repo Commit: http://git-wip-us.apache.org/repos/asf/accumulo/commit/fae7a822 Tree: http://git-wip-us.apache.org/repos/asf/accumulo/tree/fae7a822 Diff: http://git-wip-us.apache.org/repos/asf/accumulo/diff/fae7a822 Branch: refs/heads/master Commit: fae7a8224e5f259881ca744ce1aaeb062276127a Parents: 2b48d1c Author: Josh Elser <els...@apache.org> Authored: Fri May 1 00:12:22 2015 -0400 Committer: Josh Elser <els...@apache.org> 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(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/accumulo/blob/fae7a822/core/src/main/resources/org/apache/accumulo/core/conf/config-header.txt ---------------------------------------------------------------------- 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: http://git-wip-us.apache.org/repos/asf/accumulo/blob/fae7a822/docs/src/main/asciidoc/chapters/administration.txt ---------------------------------------------------------------------- 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
