What are ArcSDE log file tables?
ArcSDE geodatabases use log file tables to maintain lists of selected records. Records are written to log file tables for later use by the application whenever a selection of a specific size is made, a reconciliation or post on a versioned database is performed, or a disconnected editing checkout is done in a client application. The log file tables store the ObjectIDs of the selected features so they can be redisplayed. This allows for faster analysis and processing of information.
In ArcGIS, by default, log file tables are used if the selection set contains 100 or more records. This selection threshold of 100 features is set in the registry. It can be changed; however, ESRI does not recommend you do so. There is no proven performance reason for changing it, and doing so could even cause performance problems. In ArcIMS, if you are using server feature count mode, all selections of any size use the log file tables. For details on feature count modes in ArcIMS, consult the ArcIMS Help provided with that software.