Before attempting to debug an issue with the MDEX Engine, collect the following information.
The Dgraph creates up to five logs, although some of these logs depend on your implementation and the Guided Search components that you may be using. This topic provides a summary of these logs.
You can use these Dgraph logs to troubleshoot MDEX Engine queries, or to track performance of particular queries or updates.
The Dgraph request log is always created. You can use it to debug both queries and update processing. It contains one entry for each query processed.
You can set the path to this log by using one of these methods:
In the
AppConfig.xmlfile of the Deployment Template, specify the path set by the Dgraph component's<log-dir>element. Based on it, the Deployment Template creates the file in the following format:$component.reqlog. For example,Dgraph1.reqlogis the path to the Dgraph log for a Dgraph component with the nameDgraph1.If you are using the Dgraph from the command line, create the path to the request log in the Dgraph working directory with the filename
dgraph.reqlog.
Details about the Dgraph request log can be found in the Performance Tuning Guide.
The Dgraph error log is created only if you redirect
stderr to a file, using a command line or a
dgraph --out flag. Otherwise, error messages appear in
stderr.
The Dgraph error log includes startup messages as well as warning and
error messages. It can be configured via Dgraph flags (such as
-v). In addition, the
config?op=log-enable operation, described in an
appendix to this book, makes it possible to record more details about specific
features.
In the
AppConfig.xml file, you can specify the path set by a
Dgraph component's
<log-dir> element, using the format
$component.log. For example,
Dgraph1.log is the path to a Dgraph component with the
name
Dgraph1.
The Dgraph update log is created only if you run the Dgraph with the
--updatelog flag, or through the Deployment Template.
You can set the path to this log in the Deployment Template in the
Dgraph component
<log-dir> element, in the following format:
$component.updatelog. For example,
Dgraph1.updatelog is the path to the Dgraph update log
for a Dgraph component with the name
Dgraph1.
The Dgraph process start log is created in the Deployment Template and EAC environments for messages which occur during the Dgraph process startup. This log is typically empty. It may sometimes be useful for debugging Deployment Template or EAC issues.
You can set the path to this log by the Dgraph component
<log-dir> element, with the format
$component.start.log. For example,
Dgraph1.start.log identifies the process start log for
a Dgraph component with the name
Dgraph1.
The EQL per-query statistics log is useful if you use Endeca Query
Language (EQL). It is created only if you run the Dgraph with the
--log_stats
flag. This log is not created in the
default configuration driven by the Deployment Template.
path
For more information about the Endeca Query Language, see the MDEX Engine Developer's Guide.
