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