Sun Java System Application Server Enterprise Edition 8.2 Troubleshooting Guide

High Load Problems

High load scenarios are recognizable by the following symptoms:

If a high load problem is suspected, consider the following:


Note –

Frequently, all of these problems can be solved by making more CPU horsepower available.


Is the Tuple Log Out Of Space?

All user operations (delete, insert, update) are logged in the tuple log and executed. There tuple log may fill up because:

Solution 1

Check CPU usage, as described in Improving CPU Utilization

Solution 2

If CPU utilization is not a problem, check the disk I/O. If the disk shows contention, avoid page faults when log records are being processed by increasing the data buffer size with hadbm set DataBufferPoolSize=... If there is disk contention, follow the solutions suggested in Is There Disk Contention?

Solution 3

Look for evidence of network contention, and resolve bottlenecks.

Solution 4

Increase the tuple log buffer using hadbm set LogBufferSize=...

Is the node-internal Log Full?

Too many node-internal operations are scheduled but not processed due to CPU or disk I/O problems.

If the node-internal log is out of space, the history files contain messages showing HIGH LOAD on the node internal log.

Solution 1

Check CPU usage, as described in Improving CPU Utilization

Solution 2

If CPU utilization is not a problem, check the disk I/O. If the disk shows contention, avoid page faults when log records are being processed by increasing the data buffer size with hadbm set DataBufferPoolSize=... If there is disk contention, follow the solutions suggested in Is There Disk Contention?

Are There Enough Locks?

Some extra symptoms that identify this condition are:

Solution 1: Split Long Transactions

A transaction running on a node is not allowed to use more than 25% of the number of locks allocated on that node. Read transactions running at the “repeatable read” isolation level and the update/insert/delete transactions hold the locks until the transaction terminates. Therefore, it is recommended to split long transactions into small batch of separate transactions.

Solution 2: Increase the number of locks

Use hadbm set NumberOfLocks= to increase the number of locks.

Can You Fix the Problem by Doing Some Performance Tuning?

In most situations, reducing load or increasing the availability of resources will improve host performance. Some of the more common steps to take are:

In addition, the following resources can be adjusted to improve “HIGH LOAD” problems, as described in the Performance and Tuning Guide:

Table 3–1 HADB Performance Tuning Properties

Resource 

Property 

Size of Database Buffer 

hadbm attribute DataBufferPoolSize

Size of Tuple Log Buffer 

hadbm attribute LogBufferSize

Size of Node Internal Log Buffer 

hadbm attribute InternalLogBufferSize

Number of Database Locks 

hadbm attribute NumberOfLocks