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Title
What does TSCAN in the Sybase agent represent? -
Description
What does the value TSCAN in the Sybase Top I/O Active Tables panel Table Scan column represent?
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Resolution
This value is determined by the Top Table stored procedure used by the Sybase agent to determine the tables accessed with a table scan.
It includes the tables where the IndexID is 0 (scanning a table), while the activity is usedcount >0 and pagesread > 10.
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Additional Information
A table being scanned does not necessarily mean it doesn't have an index. It may have inefficient indexes. If the explain plan returns that the most optimal way to get results from any given query is with a table scan, it will perform one. If tables with indexes are being scanned a lot in means that those indices are inefficient.