10.10.3 Using the global buffer statistical information

(1) Outputting the global buffer statistical information and acquiring related information

When you execute the adbstat command, the global buffer statistical information is output. The output information covers the entire period from the time the HADB server was started. If you want to check the usage status of the global buffer, we recommend that you output the global buffer statistical information.

■ Outputting the global buffer statistical information

See Checking the operational status of a specific global buffer in Examples under adbstat (Perform Statistical Analysis of the HADB Server) in the manual HADB Command Reference.

We also recommend that you acquire the following types of related information when you output the global buffer statistical information:

• Server message log files

  Use the OS's cp command or a similar method to copy and acquire these files. For the storage destination of server message log files, see 10.4.2 Viewing the message logs (message log output destination).

• Global buffer name

  Execute the adbls -d gbuf command to check the global buffer name. The global buffer name that was specified in the -g option of the adbbuff operand in the server definition is output.

  For details about the adbls -d gbuf command, see adbls -d gbuf (Display Global Buffer Information) in the manual HADB Command Reference. For details about the adbbuff operand in the server definition, see 7.2.11 Operands and options related to global buffers (command format).

  Note

  You can also check the global buffer name using one of the following methods:

  • Check the message log when the HADB server starts, and determine the global buffer name from the server definition information in the output message KFAA50027-I.

  • Reference the server definition file ($ADBDIR/conf/server.def) that was used when the HADB server was started, and determine the global buffer name.

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(2) Using the global buffer statistical information and related information

By acquiring the global buffer statistical information and related information, you can check the usage status of each global buffer. You can also use the acquired global buffer statistical information and related information to perform tuning.

■ Using the global buffer statistical information and related information

1. Check the global buffer statistical information.

   In the global buffer statistical information that is output, check the following information:

   • Timestamp (the output date and time of the global buffer statistical information)

   • DBbuff_name (global buffer name)

2. Compare the Timestamp date and time with the server message log file.

   Compare Timestamp checked in step 1 and the output date and time of the message in the server message log file. By comparing Timestamp and the output date and time, you can check how the applicable global buffer was used for processing.

   Also, compare DBbuff_name checked in step 1 and the global buffer name in the KFAA50027-I message in the server message log file. By comparing DBbuff_name and the global buffer name, you can check the applicable global buffer name.

The following figure shows the concept of using the global buffer statistical information and related information.

Figure 10‒10: Using the global buffer statistical information and related information

You can also use the global buffer statistical information and related information when you perform the following types of tuning:

• (1) Using the global buffer statistical information to reduce SQL statement execution time in 13.2.2 Reducing the SQL statement execution time.

• (1) Using the global buffer statistical information to reduce the execution time of an SQL statement that creates a global work table in 13.2.3 Reducing the execution time of an SQL statement that creates a global work table.

• (1) Using the global buffer statistical information to reduce the execution time of an SQL statement that performs table scans in 13.2.5 Reducing the execution time of SQL statements that perform table scans.

• 13.3.2 Reducing the execution time of the adbidxrebuild command

• 13.3.3 Reducing the execution time of the adbgetcst command

• 13.3.4 Reducing the execution time of the adbexport command

• 13.3.5 Reducing the execution time of the adbmergechunk command

• 13.3.6 Reducing the execution time of the adbarchivechunk command

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