Release 10.1A: OpenEdge Data Management:
Database Administration

Summary

Displays general information about database activity. Figure 19–31 shows a sample Summary Activity display.

09/25/03       Activity: Summary 16:27          from 09/25/03 15:31 to 09/25/03 16:04 (2 min. 48 sec.) Event           Total   Per Sec.    |Event          Total   Per Sec. Commits          1208       0.7     |DB Reads         57        0.0 Undos               0       0.0     |DB Writes         3        0.0 Record Reads     1334       0.8     |BI Reads         13        0.0 Record Updates   1208       0.7     |BI Writes       131        0.0 Record Creates      0       0.0     |AI Writes         0        0.0 Record Deletes      0       0.0     |Checkpoints       0        0.0 Record Locks     3625       2.3     |Flushed at chkpt  0        0.0 Record Waits        0       0.0 Rec Lock Waits  0%    BI Buf Waits      0%    AI Buf Waits   0% Writes by APW   0%    Writes by BIw    96%    Writes by AIW  0% DB Size:      352K    BI size:        512K    AI Size:       0K Empty blocks:   10    Free blocks:       0    RM chain:       1 Buffer hits:    98%   Active trans:      1 0 Servers, 1 Users (1 Local, 0 Remote, 0 Batch), 1 APWs

Figure 19–31: PROMON Summary Activity display

The Summary Activity display shows the number of events that have occurred on the system, including the cumulative total and the number of events per second. The display includes the following events:

Commits — The number of transactions all users have committed.
Undos — The number of transactions rolled back.
Record Reads — The number of records read.
Record Updates — The number of records updated.
Record Creates — The number of records created.
Record Deletes — The number of records deleted.
Record Locks — The number of record locks used.
Record Waits — The number of times users have waited to access a locked record.
DB Reads — The number of database blocks read.
DB Writes — The number of database blocks written to disk.
BI Reads — The number of BI blocks read.
BI Writes — The number of BI blocks written to disk.
AI Writes — The number of AI blocks written to disk.
Checkpoints — The number of checkpoints that have been performed.
Flushed at chkpt — The number of database buffers that have been flushed to disk because they were not written by the time the checkpoint ended.

The Summary Activity display also shows the following information:

Rec Lock Waits — The percentage of record accesses that result in record lock waits. A record lock wait occurs when the database engine must wait to access a locked record.

For optimum performance, try to keep this number as low as possible. You can lower this number by modifying your application to perform shorter transactions so that record locks are held for shorter periods of time.

BI Buf Waits — The percentage of BI buffer waits. A BI buffer wait occurs when the database engine must wait to access a BI buffer.

For optimum performance, try to keep this number as low as possible. To decrease this number, allocate more BI buffers with the Before-image Buffers (-bibufs) parameter.

AI Buf Waits — The percentage of AI buffer waits. An AI buffer wait occurs when the database engine must wait to access an AI buffer.

For optimum performance, try to keep this number as low as possible. To decrease this number, allocate more AI buffers with the After-image Buffers (-aibufs) parameter.

Writes by APW — The percentage of database blocks written to disk by the APW; this is a percentage of the total number of database blocks written.

For optimum performance, try to keep this number as high as possible. To increase this number, start more APWs and increase the cluster size.

Writes by BIW — The percentage of BI blocks written to disk by the BIW; this is a percentage of the total number of BI blocks written to disk. For optimum performance, try to keep this percentage fairly high. You can increase the number of BI buffers with the -bibufs parameter.
Writes by AIW — The percentage of AI blocks written to disk by the AIW; this is a percentage of the total number of AI blocks written. For optimum performance, try to keep this percentage fairly high. You can increase the number of AI buffers with the -aibufs parameter.
DB Size — The size of your database, in kilobytes.
BI Size — The size of your BI file, in kilobytes.
AI Size — The size of your AI file, in kilobytes.
Empty blocks — The number of empty (never used) database blocks.
Free blocks — The number of blocks on the database’s free chain. The free chain is a chain of previously used and then deallocated database blocks.
RM chain — The number of blocks on the database’s RM chain. The RM chain is a chain of partially filled database blocks.
Buffer hits — The percentage of buffer hits. A buffer hit occurs when the database engine locates a database record in the buffer pool and does not have to read the record from disk.

For optimum performance, keep this number as high as possible. To increase this number, allocate more buffers with the -B parameter. Increase the number of buffers until one of the following occurs:

The number of I/Os per second is reduced to less than half the capacity of the drives.
The buffer hit rate stops improving.
The system starts paging.
Active trans — The number of active transactions.

The last line of the Summary Activity display summarizes the current number of each type of process running against the database at the time you run the Activity option. Table 19–13 defines the process types.

Table 19–13: Process types 

Field	Description
Servers	Number of servers running against your database. This is the current value at the time you run the Activity option, not a cumulative total.
Clients	Number of client sessions running. This field is further divided into the type of user: Local, Remote, or Batch. This is the current value at the time you run the Activity option, not a cumulative total.
APWs	Number of APWs running against your database. This is the current value at the time you run the Activity option, not a cumulative total.