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pmTrimNameSpace

NAME

pmTrimNameSpace - prune a performance metrics name space

C SYNOPSIS

#include <pcp/pmapi.h>

int pmTrimNameSpace()

cc ... -lpcp

DESCRIPTION

If the current Performance Metrics Application Programming Interface (PMAPI) context corresponds to a version 1 archive log of Performance Co-Pilot (PCP) performance metrics (as collected by pmlogger(1) -V1), then the currently loaded Performance Metrics Name Space (PMNS), is trimmed to exclude metrics for which no description can be found in the archive. The PMNS is further trimmed to remove empty subtrees that do not contain any performance metric.

Since PCP archives usually contain some subset of all metrics named in the default PMNS, pmTrimNameSpace effectively trims the application's PMNS to contain only the names of the metrics in the archive.

Since PCP 2.0, pmTrimNameSpace is only needed for dealing with version 1 archives. Version 2 archives actually store the "trimmed" PMNS.

Prior to any trimming, the PMNS is restored to the state as of the completion of the last pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) or implicit load (in the case of a host with a version 1 Performance Metric Collector Daemon (PMCD)) operation, so the effects of consecutive calls to pmTrimNameSpace with archive contexts are not additive.

If the current PMAPI context corresponds to a host, rather than an archive, and the host has a version 1 pmcd or a pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) call was made, then the PMNS reverts to all names loaded into the PMNS at the completion of the last pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) or implicit load operation, i.e. any trimming is undone.

On success, pmTrimNameSpace returns zero.

SEE ALSO

pmlogger(1), PMAPI(3), pmLoadASCIINameSpace(3), pmLoadNameSpace(3), pmNewContext(3) and pmns(4).

DIAGNOSTICS

PM_ERR_NOPMNS

you must have loaded a PMNS using pmLoadASCIINameSpace(3) or pmLoadNameSpace(3) before calling pmTrimNameSpace

PM_ERR_NOCONTEXT

the current PMAPI context is invalid