[back to "Optimizing server performance: Semaphores (Part 1)"]

Analysis of a Sem.Timeouts line (sidebar)
The following information analyzes sample output from a Sem.Timeouts line to narrow down where in the system the timeout occurred. Use this information in conjunction with suggestions in the Troubleshooting sections of the main article in trying to pinpoint the cause of the semaphore timeout.

To view Sem.Timeouts lines, type Show Stat Sem.Timeouts at the Domino server console. If the system has experienced a semaphore timeout, a message similar to the following appears:

Sem.Timeouts=430D:58

where 430D:58 translates to:

[digit=4][package code=3][double digit reason code=0D]:[count of occurrences]

To narrow down the focus of where the timeout occurred, look at the number in the second positional value from the left (before the colon). For example, “3” from 430D. See the table below to correspond that number with a code and the specific package (that is, grouping of system functionality) and area of the system. The output from this timeout references the NIF (Notes Indexing Facility) package, more commonly referred to as the Indexer or Update task.

The following table provides information on packages and system areas you can use to gain insight into the areas that might be requesting or holding a semaphore. This information, a subset of the information located in the GLOBERR.H file found in the Domino SDK (Software Developer's Kit), represents what we see most often in Sem.Timeouts output. For a deeper level of analysis, particularly if you have output that references a package not listed in the table below, contact Lotus Customer Support.

Area	Package Reference	Code	Typical areas of concentration
OS	PKG_OS	1	OS platform. Look closely at the paging file allocation, and ensure it is enough. Beyond that, review the OS Platform stats of CPU, Memory and Disk I/O utilization to see what is saturated.
Database	PKG_NSF	2	Core database. Refer to the Troubleshooting sections of the main article and part two of this article.
Indexer	PKG_NIF	3	Indexer (Update). Refer to the Troubleshooting sections of the main article and part two of this article.
Server	PKG_SERVER2	4	Internal Domino buffering pool scheme.

Part two of this article lists specific semaphores (the ones that most commonly occur) and provides further detail on how to map them to a specific task or area of the system. This list alsos provide information on how often specific semaphores have encountered timeouts using Domino R5, based on our experience with R5 production servers.