In SSIS, if logging is enabled with provider type as SQL Server,
sysssislog table :
Contains one row for each logging entry that is generated by packages or their tasks and containers at run time.
This table is created in the msdb database when you install Microsoft SQL Server Integration Services.
If you configure logging to log to a different SQL Server database, a sysssislog table with this format is created in the specified database.
In SSIS, if sysssislog table is not getting populated after package execution, then make sure :
i) Logging is enabled
ii) OLEDB connection for Configuration - Pointing to correct database
iii) You have sufficient permission :
GRANT EXECUTE ON SP_SSIS_ADDLOGENTRY TO [DOMAIN\USER]