I'm sure there's people here who can help you, but in order to do that it'd be really great if you could give us some more information. Stuff like:

• What version of FME are you using?
• What database are you trying to read from?
• Are you getting any error messages in the log and if so, which ones?
• Is that table exceptionally large?
• Have you set up a WHERE clause on the reader, or a SQL query to execute before reading?
• Can you read that table from the same machine using another application?