Timeout Errors in SQL occur in the following situations:
1. When a function call is used multiple times.
Solution: Assign the function's return value to a variable instead of directly calling the function multiple times. The call to variable multiple times is really a cheap and best operation.
2. Using Global and Local Temp Tables
Solution: Use of Table variable reduces the burden. This reduces the bottleneck created by the calls to the TEMP DB, as the Global and Local Temp tables are created on TEMP DB. Temp Variable as well is created on TEMP DB but variables are less costlier as discussed.
3. Setting Connection Timeout property in connection string with a lesser value.
Solution: Increase the Connection Timeout property value. The customer performing the call through SQL command may have set a maximum Timeout period for the execution to finish. If that is attained prior to complete execution of that command, then arises the timeout error with respect to the consumer.
3. Index not created on the table.
Solution: Index speeds of query retrieval. The database plan can be advanced by the process of applying indices that makes queries accomplish faster results. There may be cases wherein removal of index leads to a better solution.
4. It may be due to lock of that table,
Solution: Do not lock on table specifically in case of OLAP queries.