pmfetcharchive(3) [centos man page]

PMFETCHARCHIVE(3)					     Library Functions Manual						 PMFETCHARCHIVE(3)

NAME

       pmFetchArchive - get performance metrics directly from an archive log

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmFetchArchive(pmResult **result);

       cc ... -lpcp

DESCRIPTION

       pmFetchArchive  is  a  variant  of  pmFetch(3) that may only be used when the current Performance Metrics Application Programming Interface
       (PMAPI) context is associated with an archive log.

       The result is instantiated with all of the metrics (and instances) from the next archive record, consequently there is no notion of a  list
       of desired metrics, and the instance profile of the PMAPI context is ignored.

       It  is  expected that pmFetchArchive would be used to create utilities that scan archive logs, while the more common access to the archives
       would be via the pmFetch(3) interface.

       To skip records within the archive log, use pmSetMode(3) to change the  collection  time  within  the  current  PMAPI  context,	then  call
       pmFetchArchive.

       Note  that  the	result returned by pmFetchArchive is dynamically allocated, and must be released using pmFreeResult(3), not free(3C).  See
       pmFetch(3) and pmFreeResult(3) for further details.

       pmFetchArchive returns zero on success.

SEE ALSO

       PMAPI(3), pmFetch(3), pmFreeResult(3), pmNewContext(3), pmSetMode(3) and pmTrimNameSpace(3).

DIAGNOSTICS

       PM_ERR_NOTARCHIVE
	      the current PMAPI context is not associated with an archive log

Performance Co-Pilot							PCP							 PMFETCHARCHIVE(3)

PMGETARCHIVEEND(3)					     Library Functions Manual						PMGETARCHIVEEND(3)

NAME

       pmGetArchiveEnd - locate logical end of file for an archive log

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetArchiveEnd(struct timeval *tvp);

       cc ... -lpcp

DESCRIPTION

       Assuming  the  current PMAPI context is associated with an archive log, pmGetArchiveEnd will attempt to find the logical end of file (after
       the last complete record in the archive), and return the last recorded timestamp via tvp.  This timestamp may be passed to pmSetMode(3)	to
       reliably position the context at the last valid log record, e.g. in preparation for subsequent reading in reverse chronological order.

       For archive logs that are not concurrently being written, the physical end of file and the logical end of file are co-incident.	However if
       an archive log is being written by pmlogger(1) at the same time an application is trying to read the archive, the logical end of  file  may
       be before the physical end of file due to write buffering that is not aligned with the logical record boundaries.

       pmGetArchiveEnd	returns  an  error less than zero if the context is neither valid, nor associated with an archive, or the archive is seri-
       ously corrupted.  Otherwise, the return value is 0 if there has been no change of state since the last call, or 1 if  the  logical  end	of
       file has advanced since the last call.

       In the absence of an error, the result returned via tvp is well-defined.

       pmGetArchiveEnd preserves the positioning state of the log file prior to this function call.

PCP ENVIRONMENT

       Environment  variables  with  the prefix PCP_ are used to parameterize the file and directory names used by PCP.  On each installation, the
       file /etc/pcp.conf contains the local values for these variables.  The $PCP_CONF variable may be used to specify an alternative	configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PMAPI(3), pmFetch(3), pmFetchArchive(3), pmGetArchiveLabel(3), pmGetConfig(3), pmSetMode(3), pcp.conf(5) and pcp.env(5).

DIAGNOSTICS

       PM_ERR_NOCONTEXT
	      the current PMAPI context is either invalid, or not associated with an archive log

       PM_ERR_LOGREC
	      the archive is sufficiently damaged, that not a single valid record can be found

Performance Co-Pilot							PCP							PMGETARCHIVEEND(3)