FAQ

• The application runs normally but is not displayed in the console

• A multidimensional query returns no results, or the trace search is empty

• How to configure a tracer to segment trace logs by the hour

• The RPC Tracer does not print rpc-client-digest.log

Application runs normally but does not appear in the console

Problem

The title of this topic is self-explanatory.

Cause

DST has an underlying dependency on Simple Log Service to collect application log data. Trace information cannot be displayed if Simple Log Service is not activated or the log collection client is not installed.

Solution

Ensure that you have completed the following steps:

1. Activate Simple Log Service for your application. For more information, see Activate Simple Log Service.

2. Install the Logtail client to collect logs. For more information, see Getting Started.

Multidimensional query returns no results, or trace search is empty

Problem

This topic is self-explanatory.

Cause

The trace was invoked outside the valid time range (7-day cache), or log collection is not configured correctly.

Solution

Perform the following checks:

• Check if the trace was invoked within the valid time range. DST caches logs for 7 days. You cannot query trace data that is older than this cache period.

• Check if Simple Log Service is activated and if the log collection client is installed correctly. For more information, see The application runs normally but is not displayed in the console.

How to configure a tracer to segment trace logs by the hour

Background

• By default, the middleware trace log is segmented by day. A new log is generated every 24 hours.

• In some cases, you may want to segment the trace log every hour in SOFABoot Enterprise Edition.

Solution

1. Add the dependency for the tracer Enterprise Edition JAR package to the pom.xml file.

   <dependency>
         <groupId>com.alipay.sofa</groupId>
         <artifactId>tracer-enterprise-sofa-boot-starter</artifactId>
   </dependency>

2. Add the following configuration to the application.properties file: com.alipay.sofa.tracer.tracerGlobalRollingPolicy=.yyyy-MM-dd_HH.

RPC Tracer does not print rpc-client-digest.log

Problem

The RPC Tracer does not print the rpc-client-digest.log file but prints the rpc-client-stat.log file, even though an RPC service has been invoked.

Cause

The log was manually initialized in the code, and the isSampled parameter was set to false.

Solution

The SOFABoot framework automatically prints logs. Do not create them manually. Modify the code to remove the manual initialization.

Example: