Logging and Tracing 5 - Understanding Logs
Big logs are usually a big mess. Its not easy to understand the relation and order of log entries of interest and get rid of unrelated information. Beside the viewer, that can display logs and traces and other signals together in one domain line, Value Tables can help to understand this mess.
This article is based on impulse version 1.3/1.4
A Value Table shows one or more signals in tabular form. You can select the samples and copy&paste to get CSV.
You can let it be displayed if you open Window in the upper left tool-bar, then choose Show View->Other, and within the window that opens you select Impulse and select the Value Table.
To show signals in this table, just select one or more signal in the viewer (assumes the default setting of the table).
Instead of using selection, you can use the Show In context menu of the viewer or Navigator. This will automatically freeze the input.
You can display and use up to 4 tables.
Sync selection/active cursor over multiple tables
One great feature of impulse is that you can sync the selection of the viewer and the value tables. You can disable sync in the tables tool-bar (Sync Selection).
This means,if you move or change the active cursor, the tables will show the valid samples selected at that time. If you change the selection, the viewer and the other tables will change their selections too.
Search and filter
Beside the viewer, that allows you to define complex search expressions, the tables allow to filter and search for samples too - in a more easy way.
To limit the number of samples in the table, just type in an expression into the filter field. Impulse will just show those samples that contain that expression in one of its fields (not case sensitive).
To find or traverse over certain samples, use the find dialogue. It looks like and behaves like a normal text find dialogue. You can search in any field.
Inspection and Text Sync
Two additional feature might be of interest. Like the viewer, also the Value Table has an Inspection Dialogue. If you double-click on a sample it will open to show more detailed information.
If the log data is read from a text file using the pattern log reader, the table will offer the possibility to sync with the text log file. If you select Show-in Text Editor, impulse will open the file (if not already opened) and set the cursor to the sample position.
Last, not least, Markers can help to remember sample and event locations. Use the configuration context menu (Signal Marker -> Add ...) to add markers at interesting positions. If you save the record into a file resource, the eclipse Bookmark and Task View can be used to open the file and find the defined marker locations.
The final article of this series will be about generating statistics and charts.