Query information logging captures table and index read access statistics for each table and index identified in a query against an OpenEdge database. Read access statistics includes reads by all users connected to the database.
Note: Query information logging omits read access statistics for DataServers and temp-tables. Additionally, read access statistics are not logged for preparing a dynamic query.
Table read access statistics provide the number of times read access has occurred on a table. Use Base Table (-basetable) with Table Range Size (-tablerangesize) to specify the range of tables for which you want to collect statistics. Table statistics are stored in the _TableStat-Read field of the _TableStat Virtual System Tables (VST).
Index read access statistics provide the number of times read access has occurred on an index. Use Base Index (-baseindex) with Index Range Size (-indexrangesize) to specify the range of indexes for which you want to collect statistics. Index statistics are stored in the _IndexStat-Read field of the _IndexStat VST.
Read access statistics information is located in the Query Statistics after the DB Block access statistics. For each table in the query, or a non-pre-pass query, the client writes the read access statistics in the Query Statistics once the query completes. For a pre-pass query, the client writes the read access statistics in the Query Statistics for building the results list, and again once the query completes. This differentiates the read accesses required to build the result list from those required to iterate through the list.
In order to get the table and index read statistics, the user must ensure the queried tables and indices are within the ranges specified by the startup parameters Base Table (-basetable)/Table Range Size (-tablerangesize) and Base Index (-baseindex)/Index Range Size (-indexrangesize) ranges. If your query accesses tables or indices outside these ranges, query information logging cannot determine the access statistics for the tables or indices, and displays "UNAVAILABLE" for the read access statistics.
For more information on the referenced startup parameters, see OpenEdge Deployment: Startup Command and Parameter Reference. For more information on VSTs, see OpenEdge Data Management: Database Administration.
