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NAME | C SYNOPSIS | DESCRIPTION | DIAGNOSTICS | SEE ALSO | COLOPHON |
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PMFETCHARCHIVE(3) Library Functions Manual PMFETCHARCHIVE(3)
pmFetchArchive, pmFetchHighResArchive - get performance metric
values directly from archive logs
#include <pcp/pmapi.h>
int pmFetchArchive(pmResult **result);
int pmFetchHighResArchive(pmHighResResult **result);
cc ... -lpcp
The pmFetchArchive and pmFetchHighResArchive APIs are variants of
the pmFetch(3) and pmFetchHighRes(3) interfaces that may only be
used when the current Performance Metrics Application Programming
Interface (PMAPI) context is associated with a set of archive
logs.
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.
pmFetchArchive and pmFetchHighResArchive may return a result in
which numpmid is zero. This is a <mark> record that indicates a
temporal discontinuity in the time series of performance metrics.
This can happen at the boundary between archive logs in a set or
if the archive log associated with the current PMAPI context was
created using pmlogextract(1) to concatenate two or more PCP
archive logs, and the <mark> record marks a point in time between
the end of one input archive and the start of the next input
archive.
It is expected that pmFetchArchive and pmFetchHighResArchive will
be used to create utilities that scan sets of archive logs, while
the more common access to the archives would be via the pmFetch
and pmFetchHighRes interfaces.
To skip records within the set of archive logs, use pmSetMode(3)
or pmSetModeHighRes(3) to change the collection time within the
current PMAPI context, then call either pmFetchArchive or
pmFetchHighResArchive.
Note that the result returned by both pmFetchArchive and
pmFetchHighResArchive is dynamically allocated, and must be
released using either pmFreeResult(3) or pmFreeHighResResult(3),
but not free(3). See pmFetch(3), pmFetchHighRes(3),
pmFreeResult(3) and pmFreeHighResResult(3) for further details.
Both pmFetchArchive and pmFetchHighResArchive returns zero on
success.
PM_ERR_NOTARCHIVE
the current PMAPI context is not associated with a set of
archive logs
PMAPI(3), pmFetchHighRes(3), pmSetModeHighRes(3),
pmFreeHighResResult(3), pmFetch(3), pmFreeResult(3),
pmNewContext(3), pmSetMode(3) and pmTrimNameSpace(3).
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at
⟨http://www.pcp.io/⟩. If you have a bug report for this manual
page, send it to pcp@groups.io. This page was obtained from the
project's upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2023-06-23.
(At that time, the date of the most recent commit that was found
in the repository was 2023-06-21.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMFETCHARCHIVE(3)
Pages that refer to this page: pcpintro(3), pmfetch(3), pmgetarchiveend(3), pmregisterderived(3), pmsetmode(3)
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HTML rendering created 2023-06-24 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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