KnowledgeBase/CII.md

@@ -1298,6 +1298,34 @@ A test application showing its use is here:
 ### [OLDB]
 
 
+--------------------------------------------------------------------------
+--------------------------------------------------------------------------
+--------------------------------------------------------------------------
+### Less or More Logs [OLDB Log]
+
+**Problem**
+
+You are using the OLDB API, and you are getting more logs than you asked for. For example, simply testing for the existence of a datapoint: `[ERROR] Path not found config exception occurred: Path oldb/datapoints/myroot/somedp, version 1 not found`
+
+or, the OLDB API seems to be misbehaving, and you want more logs.
+
+**Solution**
+
+Please read the article "[Adjust CII Log Levels [Log]](#user-content-adjust-cii-log-levels-log)" in the Log section of this Knowledge Base. The relevant logger names for the OLDB API are:
+
+```
+CiiOldb
+CiiOldbDirectoryTreeProvider
+CiiOldbFactory
+CiiOldbRedisDataPointProvider
+CiiOldbRemoteDataPointProvider
+CiiOldbRemoteFileProvider
+```
+
+Example: to turn off ERROR logs for testing the existence of non-existing datapoints, use:
+```
+log4cplus.logger.CiiOldbRemoteDataPointProvider=FATAL
+```
 
 
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@@ -1740,8 +1768,6 @@ Type "help", "copyright", "credits" or "license" for more information.
 ### [Log]
 
 
-
-
 --------------------------------------------------------------------------
 --------------------------------------------------------------------------
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@@ -1778,6 +1804,72 @@ elt.log.CiiLogManager.set_log_level(name_or_logger: Union\[str, logging.Logger\]
 ```
 
 
+--------------------------------------------------------------------------
+--------------------------------------------------------------------------
+--------------------------------------------------------------------------
+### Adjust CII Log Levels [Log]
+
+With plain CII (no application frameworks on top), you define a log config file (myapp.logconfig):
+
+```
+log4cplus.rootLogger=INFO, STDOUT
+log4cplus.appender.STDOUT=log4cplus::ConsoleAppender
+log4cplus.appender.STDOUT.layout=elt::log::layout::CiiSimpleLayout
+
+# other loggers, e.g. OLDB or MAL
+log4cplus.logger.CiiOldb=FATAL
+```
+
+The name of the log config is your choice, but to comply with the rules of "waf install", best use such a project structure:
+```
+myapp/
+├── resource
+│   └── config
+│       └── myapp.logconfig
+├── src
+│   ├── myapp.cpp
+└── wscript
+```
+
+
+Then apply the log config from your application (myapp.cpp):
+```
+#include <ciiLogManager.hpp>
+int main(int ac, char *av[]) {
+  ::elt::log::CiiLogManager::Configure("resource/config/myapp.logconfig");
+  log4cplus::Logger root_logger = ::elt::log::CiiLogManager::GetLogger();
+  root_logger.log(log4cplus::INFO_LOG_LEVEL, "Message via root logger");
+  return 0;
+}
+```
+
+
+
+**List of Loggers**
+Generally, to learn about all loggers that are active in your application, add this (temporarily) to your application:
+
+```
+#include <ciiLogManager.hpp>
+[...]
+std::cout << "Current loggers (in addition to root logger):" << std::endl;
+std::vector<log4cplus::Logger> list = log4cplus::Logger::getCurrentLoggers();
+for (int i=0,n=list.size(); i<n; i++) {
+   log4cplus::Logger elem = list[i];
+   std::cout << elem.getName() << std::endl;
+}
+```
+
+Note: With the next version of CII, the logger name will be included in log messages by default.
+
+
+**Log Format**
+To use a different log format (which CII allows, but the Control System guidelines do not), you can modify the above config like this:
+
+```
+#log4cplus.appender.STDOUT.layout=elt::log::layout::CiiSimpleLayout
+log4cplus.appender.STDOUT.layout=log4cplus::PatternLayout
+log4cplus.appender.STDOUT.layout.ConversionPattern=[%-5p][%D{%Y/%m/%d %H:%M:%S:%q}][%-l][%t] %m%n
+```