CHANNELCNT

Number of open I/O channels permitted each OpenVMS process at any one time

This parameter is critical to the successful execution of the DBMS Server. If the setting is too large, it wastes system memory; if too small, it limits Ingres I/O capabilities. Since the DBMS is multi-threaded, it effectively requires the same CHANNELCNT setting as if it were several individual processes.

 

 

Use the following formula to calculate an approximate value, where sessions is the total number of connected sessions and file_limit is the total number of files that can be open at one time:

CHANNELCNT = (sessions * 4) + file_limit

In general, set CHANNELCNT to a very large number.

The file_limit (fillm) requirements will vary over time. The DBMS Server will, at most, open every file in every database, plus approximately five for the transaction log and error log files.

GBLSECTIONS

Determines the maximum number of global sections that can be made known to the system by allocating the necessary storage for the Global Storage Table (GST) entries

Example value for Alpha: 800

Several Ingres components use global pages of memory to enable multiple processes to share data.

Examples are:

GBLPAGES

Determines the size of the global page table and the limit for the total number of global pages that can be created

Example value for Alpha:

250,000

GBLPAGFIL

Establishes the maximum number of global pages with page file “Backing Storage Address” storage that can be created

Example Value for Alpha: 40,000

On Alpha, memory pages are at least 8 KB in size. At this size, four Ingres pages fit in each Alpha memory page. Note that Alpha pages can be from 8 KB to 16 KB in size. See your OpenVMS Alpha documentation.

To examine entries and available pages and sections, use the INSTALL utility and issue LIST/GLOBAL and LIST/GLOBAL/SUMMARY.

NPAGEDYN

Non-paged dynamic pool; determines the number of bytes to allocate for the non-pages dynamic pool

Used in allocating the logging and locking system in previous Ingres releases.

Ingres uses GBLPAGES (global pages) rather than NPAGEDYN and NPAGEVIR to allocate the logging and locking system shared memory at startup time.

NPAGEVIR

Virtual non-paged pool; determines the number of bytes to which the non-paged pool may be extended

Used in allocating the logging and locking system in previous Ingres releases.

Ingres uses GBLPAGES (global pages) rather than NPAGEDYN and NPAGEVIR to allocate the logging and locking system shared memory at startup time.

PQL_*

PQL_parameters; PQL_D is the default and PQL_M is the minimum process quotas that OpenVMS uses when creating detached processes (of which Ingres generates several)

If a value is not specified on the command line when Ingres processes are started, the PQL default is used. If the process specifies a value below the PQL minimum, the current minimum is used. If the creator has DETACH privilege, any of the values can be overridden, which is crucial to the successful startup of Ingres processes.

To examine the resulting process configuration, use:

SHOW PROCESS/QUOTA/ID=pid

VIRTUALPAGECNT

Maximum virtual page count; determines the total number of pages that can be mapped for a process, which can be divided in any fashion between P0 and P1 space

Beginning with OpenVMS 7.0, this parameter ceased to be tunable on Alpha as the process page tables have migrated from system space to a dedicated page table space. See your OpenVMS documentation for details.

The DBMS Server process can grow to require large numbers of virtual pages due to the complexity of its facilities and their various caches. It is critical that this process be able to expand its memory regions as necessary.

If an error occurs while trying to expand the virtual size of the server, first examine the process page file quota, and then examine this system-wide limit. To do so, set the process page file quota to the current VIRTUALPAGECNT and start the server. If this does not resolve the problem, this parameter needs to be adjusted upwards.

To examine current usage, use: SHOW PROCESS/QUOTA/ID=pid

WSMAX

Maximum size of process working set; determines the system-wide maximum size of a process working set, regardless of process quota

Example value for Alpha: 130,000

This parameter limits the size of the physical memory that any OpenVMS process can grow to consume. To prevent Ingres processes from spending overhead page faulting, be sure to configure them with a working set large enough to reduce or eliminate the amount of swapping and/or paging required.

Distinguish hard faults (disk reads/writes, which are expensive) from soft faults (memory read/writes, which are more tolerable).