Progress
Version 9
Product Update Bulletin


Cursor and Connection Use Monitoring

Monitor the use of your managed connections to tune the number of connections you allocate. If you regularly exceed your allocation, consider increasing the number of managed connections. If you never use your total allocation, consider decreasing the number of managed connections.

Connections

The DataServer log contains messages indicating the status of connections. At startup, the number of managed connections initialized is written to the log file. If connections are rejected, this is also logged. If a connection from the ODBC connection pool cannot be reused, the ODBC driver issues the message “DEAD Connection” which is written to the log file.

At the end of a session, the DataServer writes summary information about cursor use. The summary contains the following information:

When debug logging is enabled with the “-Dsrv qt_debug,cursor” switch, a summary of connection activity is written to the log file. This summary contains:

The following excerpt from a dataserv.lg file shows the summary of the managed connection activity written when the “-Dsrv qt_debug,cursor” switch is used, plus the standard messages.

16:32:09 : Standard secondary connection: 
16:32:09 : Connection chain 0xbc6e64: num_conns 1 
16:32:09 : Connection chain 0xbc6e64: peak_conns 1 
16:32:09 : Connection chain 0xbc6e64: high_conns 1 
16:32:09 : Connection chain 0xbc6e64: low_conns 0 
16:32:09 : Connection chain 0xbc6e64: num_off_conns 1 
16:32:09 : Connection chain 0xbc6e64: num_on_conns 1 
16:32:09 : Connection chain 0xbc6e64: sum_active 1 
16:32:09 : Connection chain 0xbc6e64: Needed Connections: 1, (Needed 4 less 
than requested) 
16:32:09 : Connection chain 0xbc6e64: Peak Connections: 1, (Peaked at 4 less 
than requested) 
16:32:09 : Connect: 0x1012398    Stmt: 0x1b95f80   Handle: 0x1011d98   Crc: 
1613 Proprty:      Statement dropped 
16:32:09 : Statement cache (-Dsrv PRGRS_PREPCACHE setting) reuse ratio is 0. 

For more information on using the qt_debug option to the -Dsrv switch, see Progress DataServer for Microsoft SQL Server Guide .

Cursors

Cursor downgrades are monitored by the DataServer. For firehose cursors, the DataServer counts the number of times a cursor is downgraded, and writes the count to the log file at the end of the session. For downgrades of Fast Forward-Only cursors, a message is written to the log file when the downgrade occurs. Consider increasing the number of DataServer managed connections if firehose cursors are frequently downgraded.

Statement Cache

The reuse of the statement cache is calculated as a ratio. Firehose cursors decrease the probability of a statement being reused. A reuse ratio of 3 indicates that statements are reused an average of 3 times. Reuse ratios of 3 or higher indicate good utilization of the statement cache. Reuse ratios less than 1 indicate poor utilization of the statement cache. If your ratio is less than 1, consider disabling the statement cache with “-Dsrv PRGRS_PREPCACHE,0”. For more information on the PRGRS_PREPCACHE option to the -Dsrv switch, see Progress DataServer for Microsoft SQL Server Guide .


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