JDBC Type 2 Driver Programmer's Reference for SQL/MX Release 3.2.1 (H06.26+, J06.15+)
• Combining external statement cache with MFC does not yield memory benefits. The WebLogic
Server (WLS) statement cache is an example of external statement cache. It is recommended
that you use the JDBC/MX T2 statement cache.
• MFC is not supported for BLOB and CLOB data types.
Troubleshooting MFC
The troubleshooting of MFC includes:
• “Benefits of MFC” (page 59)
• “Setting an Environment for MFC” (page 59)
• “.lock Files” (page 59)
• “.mdf Files” (page 59)
• “Disk Activity” (page 59)
• “Enable Fileset and OSS Caching” (page 59)
• “Known Issues” (page 61)
Benefits of MFC
JDBC applications using the java.sql.PreparedStatement object result in lower processor
utilization, lower memory consumption, and better response time.
Setting an Environment for MFC
See “Enabling MFC” (page 58).
.lock Files
The *.lock files are generated for every query that pass through the MFC module file creation
process. These files are also used for synchronizing, so that different connections do not re-create
the same module file. These *.lock files are deleted once the binary module in the
/usr/tandem/sqlmx/USERMODULES directory is created successfully.
The *.lock files are not deleted for the queries that cannot create module files.
.mdf Files
These temporary files are generated during preprocessing. These .mdf files are retained for easier
support and troubleshooting.
Disk Activity
The MFC access plans, stored in the disk OSH location (/usr/tandem/sqlmx/USERMODULE),
increases the process or utilization of the disks. To overcome this problem, use the fileset for that
directory. It is beneficial to have OSS caching on data volumes. To enable fileset and OSS caching,
see “Enable Fileset and OSS Caching” (page 59).
NOTE: If a DDL is altered, it is recommended that you run the management script ( mgscript
) to delete module files associated with that table or catalog. For information on the management
script, see Managing MFC in the HP NonStop SQL/MX Connectivity Service Manual.
Enable Fileset and OSS Caching
To add a fileset pointing to the USERMODULES directory, perform the following steps:
1. At a TACL prompt, enter:
SCF
Troubleshooting MFC 59