MSSQLSERVER_8623
Applies to: 
SQL Server
Details
| Attribute | Value |
|---|---|
| Product Name | SQL Server |
| Event ID | 8623 |
| Event Source | MSSQLSERVER |
| Component | SQLEngine |
| Symbolic Name | OPTIMIZER_NOPLAN_ERR |
| Message Text | The query processor ran out of internal resources and could not produce a query plan. This is a rare event and only expected for extremely complex queries or queries that reference a very large number of tables or partitions. Please simplify the query. If you believe you've received this message in error, contact Customer Support Services for more information. |
Explanation
The Query Optimizer is unable to generate a query plan due to either running out of resources or the query being too complex, two different states can be returned for this error
- State 1 - The query timed out due to the plan being too complex
- State 2 - The query ran out of resources - Memory
User Action
Simplify the query by breaking the query into multiple queries along the largest dimension. First, remove any query elements that aren't necessary, then try adding a temp table and splitting the query in two. Note that if you move a part of the query to a subquery, function, or a common table expression that isn't sufficient because they get recombined into a single query by the compiler. You can also, try adding hints to force a plan earlier, for example OPTION (FORCE ORDER).