Problem Note 31564: Performance problems occur when you use the CASE expression with DBMS tables
Creating a character column (using the CASE expression) to evaluate a numeric column can cause performance problems when you are working with database management system (DBMS) tables. The problem occurs because of a failure in the implicit Pass-Through facility. This failure causes all rows of the DBMS table or tables to be returned to the SAS® System before the CASE expression is evaluated.
You can use the SASTRACE= system option in an OPTIONS statement to determine whether suspected performance problems are a result of the CASE expression.
options sastrace=',,d,d' sastraceloc=saslog nostsuffix;
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If performance problems are a result of the CASE expression, you will see the following messages in the SAS log:
SAS_SQL: Types mismatch. Character data expected.
SAS_SQL: Unable to convert the query to a DBMS specific SQL statement due to an error.
ACCESS ENGINE: SQL statement was not passed to the DBMS, SAS will do the processing.
Select the Hot Fix tab in this note to access the hot fix for this issue.
Operating System and Release Information
| SAS System | Base SAS | z/OS | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft® Windows® for 64-Bit Itanium-based Systems | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows Server 2003 Datacenter 64-bit Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows Server 2003 Enterprise 64-bit Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows XP 64-bit Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft® Windows® for x64 | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows 2000 Advanced Server | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows 2000 Datacenter Server | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows 2000 Server | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows 2000 Professional | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows NT Workstation | 9.1 TS1M3 SP4 | 9.1 TS1M3 SP4 |
| Microsoft Windows Server 2003 Datacenter Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows Server 2003 Enterprise Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows Server 2003 Standard Edition | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Microsoft Windows XP Professional | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Windows Vista | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| 64-bit Enabled AIX | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| 64-bit Enabled HP-UX | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| 64-bit Enabled Solaris | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| HP-UX IPF | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Linux | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Linux on Itanium | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| OpenVMS Alpha | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
| Tru64 UNIX | 9.1 TS1M3 SP4 | 9.2 TS1M0 |
*
For software releases that are not yet generally available, the Fixed
Release is the software release in which the problem is planned to be
fixed.
Creating a character column (using the CASE expression) to evaluate a numeric column can cause performance problems.
| Type: | Problem Note |
| Priority: | high |
| Date Modified: | 2008-05-19 10:14:40 |
| Date Created: | 2008-03-24 07:40:39 |
