• Processes / Threads
• Files / Sockets
• Sys V IPC Semaphores
• Sys V IPC Shared memory
• Process memory / Address space
• HP-UX evp driver is required

The following sections discuss HP-UX kernel parameters involved.

You may have to increase some of the HP-UX kernel parameters beyond the default values, depending on your number of eloqdb servers and their eloqdb.cfg settings like Threads or BufferCache, for example.

Note that the discussion below only explains the requirements for the eloqdb database server(s). When adjusting kernel parameters, you need to also take into account any requirements by other applications as well as the operating system itself. So you will typically add to existing settings, to be on the safe side.

Processes / Threads

• nproc - limits the number of processes allowed to exist simultaneously
• maxuprc - limits the maximum number of concurrent user processes per user
• nkthread - limits the number of threads allowed to run simultaneously
• max_thread_proc - defines the maximum number of concurrent threads allowed per process.

Each eloqdb server process creates a small number of internal OS threads, typically below 10, and one additional OS thread for every concurrent DB client connection (regardless of the number of DBOPENs by each client).

Use

nkthread        >= SUM of "10 + max number of clients (Threads)" per eloqdb
max_thread_proc >= MAX of "10 + max number of clients (Threads)" per eloqdb

For example:

eloqdb server A: Threads = 1000
eloqdb server B: Threads =  300
eloqdb server C: Threads =  200

nkthread        >= 1530  ( 3*10+1000+300+200 )
max_thread_proc >= 1010  ( 10+1000 )

• maxfiles_lim - hard maximum number of file descriptors per process

The default maxfiles_lim by HP-UX is typically sufficient, unless you have a server with a very large maximum number of concurrent clients.

Sys V IPC semaphores

• semmns - number of System V IPC system-wide semaphores
• semmni - number of System V IPC system-wide semaphore identifiers
• semmnu - maximum number of System V IPC undo structures for processes
• semume - maximum number of System V IPC undo entries per process

When using Sys V IPC semaphores, the eloqdb server allocates a semaphore identifier with 2 semaphores for each concurrent client connection and also makes use of SEM_UNDO operations for each of these client sessions.

Unless you have a large number of eloqdb servers, the HP-UX default for semmnu will typically be sufficient. However, you may need to increase the semmns, semmni and especially the semume setting in some cases.

Use

semmni >= SUM of "max number of clients (Threads)" per eloqdb
semmns >= SUM of 2 * "max number of clients (Threads)" per eloqdb
semmnu >= number of eloqdb servers
semume >= MAX of "max number of clients (Threads)" per eloqdb

For example:

eloqdb server A: Threads = 1000
eloqdb server B: Threads =  300
eloqdb server C: Threads =  200

semmni >= 1500  ( 1000+300+200 )
semmns >= 3000  ( 2*1000+2*300+2*200 )
semmnu >= 3
semume >= 1000

• shmmni - number of System V shared memory segment identifiers in the system
• shmmax - maximum size (in bytes) for a System V shared memory segment
• shmseg - maximum number of System V shared memory segments per process

For EnableIPC=2 (the default) the eloqdb server allocates a single shared memory segment for communicating with local database clients. The segment size depends on the configured max number of clients, ie [config] Threads. For EnableIPC=1 the eloqdb server allocates a separate 32 KB segment for each database client.

Unless you have a large number of eloqdb servers or use EnableIPC=1, the HP-UX defaults for shmmni and shmseg will typically be sufficient.

With EnableIPC=2 use

shmmni >= number of eloqdb servers

shmmni >= SUM of "max number of clients (Threads)" per eloqdb
          plus number of eloqdb servers

shmseg >= MAX of "max number of clients (Threads)" per eloqdb

Process memory / Address space

• maxdsiz, maxdsiz_64bit - maximum size (in bytes) of the data segment for any user process

The data segment sizes of processes are limited by the maxdsiz or maxdsiz_64bit kernel parameters.

The 64-bit eloqdb servers do not only allocate stack space for OS level threads handling concurrent client sessions from their data segment, but also allocate memory for the dedicated BufferCache this way. They only use shared memory for the client communication (with EnableIPC > 0).

Depending on your eloqdb server settings for [Config] Threads as well as [Config] BufferCache, you may need to increase the maxdsiz_64bit.

Note that the BufferCache memory is allocated during startup of the eloqdb server process whereas the stack space for OS level threads handling concurrent client sessions grows as these sessions connect.

Note that HP-UX on Itanium uses 256 KB stack size per thread.

HP-UX evp driver is required

lsdev -C pseudo | grep evp
ls /dev/poll