Provided by: pcp_5.3.7-1_amd64 bug


       pmlogextract - reduce, extract, concatenate and merge Performance Co-Pilot archives


       pmlogextract  [-dfmwxz?]   [-c  configfile]  [-S  starttime] [-s samples] [-T endtime] [-v
       volsamples] [-Z timezone] input [...] output


       pmlogextract reads one or more Performance Co-Pilot (PCP) archive logs identified by input
       and  creates  a  temporally  merged  and/or reduced PCP archive log in output.  input is a
       comma-separated list of names, each of which may be the base name of  an  archive  or  the
       name  of a directory containing one or more archives.  The nature of merging is controlled
       by the number of input archive logs, while the nature of data reduction is  controlled  by
       the  command  line  arguments.   The  input(s) must be sets of PCP archive logs created by
       pmlogger(1) with performance data collected from the same host, but usually over different
       time  periods and possibly (although not usually) with different performance metrics being

       If only one input is specified, then the default behavior simply copies the input  set  of
       PCP  archive  logs, into the output PCP archive log.  When two or more sets of PCP archive
       logs are specified as input, the sets of logs are merged (or concatenated) and written  to

       In  the  output archive log a <mark> record may be inserted at a time just past the end of
       each of the input archive logs to indicate a possible temporal discontinuity  between  the
       end  of  one  input archive log and the start of the next input archive log.  See the MARK
       RECORDS section below for more information.  There is no <mark> record after  the  end  of
       the last (in temporal order) of the input archive logs.


       The available command line options are:

       -c config, --config=config
            Extract  only the metrics specified in config from the input PCP archive log(s).  The
            config  syntax  accepted  by  pmlogextract  is  explained  in  more  detail  in   the
            Configuration File Syntax section.

       -d, --desperate
            Desperate mode.  Normally if a fatal error occurs, all trace of the partially written
            PCP archive output is removed.  With the -d option, the output  archive  log  is  not

       -f, --first
            For  most  common uses, all of the input archive logs will have been collected in the
            same timezone.  But if this is not the case, then pmlogextract must choose one of the
            timezones  from  the  input  archive  logs  to be used as the timezone for the output
            archive log.  The default is to use the timezone from the  last  input  archive  log.
            The -f option forces the timezone from the first input archive log to be used.

       -m, --mark
            As  described  in  the MARK RECORDS section below, sometimes it is possible to safely
            omit <mark> records from the output archive.  If the -m option is specified, then the
            epilogue  and prologue test is skipped and a <mark> record will always be inserted at
            the end of each input archive (except the last).  This is the original behaviour  for

       -S starttime, --start=starttime
            Define  the  start  of  a  time window to restrict the samples retrieved or specify a
            ``natural'' alignment of the output sample times; refer to PCPIntro(1).  See also the
            -w option.

       -s samples, --samples=samples
            The  argument  samples  defines  the  number  of samples to be written to output.  If
            samples is 0 or -s is not specified, pmlogextract will sample until the  end  of  the
            PCP  archive  log,  or the end of the time window as specified by -T, whichever comes
            first.  The -s option will override the -T option if it occurs sooner.

       -T endtime, --finish=endtime
            Define the termination of a time window to restrict the samples retrieved or  specify
            a  ``natural''  alignment of the output sample times; refer to PCPIntro(1).  See also
            the -w option.

       -v volsamples
            The output archive log is potentially a multi-volume data  set,  and  the  -v  option
            causes  pmlogextract  to  start  a  new volume after volsamples log records have been
            written to the archive log.

            Independent of any -v option, each volume of an archive is limited to  no  more  than
            2^31  bytes,  so  pmlogextract will automatically create a new volume for the archive
            before this limit is reached.

       -w   Where -S and -T specify a time window within the same day, the -w flag will cause the
            data  within  the time window to be extracted, for every day in the archive log.  For
            example, the options -w -S @11:00 -T @15:00 specify that pmlogextract should  include
            archive  log  records  only for the periods from 11am to 3pm on each day.  When -w is
            used, the output archive log will contain <mark> records  to  indicate  the  temporal
            discontinuity between the end of one time window and the start of the next.

       -x   It  is  expected  that  the metadata (name, PMID, type, semantics and units) for each
            metric will be consistent across all of the input PCP archive log(s)  in  which  that
            metric  appears.   In  rare  cases,  e.g.  in  development,  in QA and when a PMDA is
            upgraded, this may not be the case and pmlogextract will report the issue  and  abort
            without  creating  the  output archive log.  This is done so the problem can be fixed
            with pmlogrewrite(1) before retrying the merge.  In unattended or QA environments  it
            may  be  preferable  to  force  the  merge  and  omit the metrics with the mismatched
            metadata.  The -x option does this.

       -Z timezone, --timezone=timezone
            Use timezone when displaying the date and time.  Timezone is in  the  format  of  the
            environment  variable TZ as described in environ(7).  The default is to initially use
            the timezone of the local host.

       -z, --hostzone
            Use the local timezone of the host from the input archive logs.  The  default  is  to
            initially use the timezone of the local host.

       -?, --help
            Display usage message and exit.


       The  configfile contains metrics of interest - only those metrics (or instances) mentioned
       explicitly or implicitly in the configuration file will be included in the output archive.
       Each  specifications  must  begin  on  a  new  line,  and  may  span multiple lines in the
       configuration file.  Instances may also be specified, but they are optional.   The  format
       for each specification is

               metric [[instance[,instance...]]]

       where metric may be a leaf or a non-leaf name in the Performance Metrics Name Space (PMNS,
       see PMNS(5)).  If a metric refers to a  non-leaf  node  in  the  PMNS,  pmlogextract  will
       recursively  descend  the  PMNS  and  include all metrics corresponding to descendent leaf

       Instances are optional, and may be specified as a list of one or  more  space  (or  comma)
       separated  names,  numbers  or strings (enclosed in single or double quotes).  Elements in
       the list that  are  numbers  are  assumed  to  be  internal  instance  identifiers  -  see
       pmGetInDom(3)  for more information.  If no instances are given, then all instances of the
       associated metric(s) will be extracted.

       Any additional white space is ignored and comments may be added with a `#' prefix.


       This is an example of a valid configfile:

               # config file for pmlogextract

               kernel.percpu.cpu.sys ["cpu0","cpu1"]


       When more than one input archive log contributes performance data to  the  output  archive
       log,  then  <mark>  records  may  be  inserted to indicate a possible discontinuity in the
       performance data.

       A <mark> record contains a timestamp and no performance data and is used to indicate  that
       there  is  a  time  period  in  the PCP archive log where we do not know the values of any
       performance metrics, because there was no pmlogger(1) collecting performance  data  during
       this  period.   Since  these periods are often associated with the restart of a service or
       pmcd(1) or a system, there may be considerable doubt as to the continuity  of  performance
       data across this time period.

       Most  current archives are created with a prologue record at the beginning and an epilogue
       record at the end.  These records identify the state of pmcd(1) at the time,  and  may  be
       used  by  pmlogextract  to determine that there is no discontinuity between the end of one
       archive and the next output record, and as a consequence the <mark> record can  safely  be
       omitted from the output archive.

       The  rationale  behind  <mark>  records may be demonstrated with an example.  Consider one
       input archive log that starts at 00:10 and ends at 09:15 on  the  same  day,  and  another
       input  archive  log  that  starts at 09:20 on the same day and ends at 00:10 the following
       morning.  This  would  be  a  very  common  case  for  archives  managed  and  rotated  by
       pmlogger_check(1) and pmlogger_daily(1).

       The output archive log created by pmlogextract would contain:
       00:10.000    first record from first input archive log
       09:15.000    last record from first input archive log
       09:15.001    <mark> record
       09:20.000    first record from second input archive log
       01:10.000    last record from second input archive log

       The  time  period  where  the performance data is missing starts just after 09:15 and ends
       just before 09:20.  When the output archive log is processed with any of the PCP reporting
       tools,  the <mark> record is used to indicate a period of missing data.  For example using
       the output archive above, imagine one was reporting the average  I/O  rate  at  30  minute
       intervals  aligned  on  the hour and half-hour.  The I/O count metric is a counter, so the
       average I/O rate requires two valid values from consecutive sample times.  There would  be
       values  for  all  the  intervals  ending  at 09:00, then no values at 09:30 because of the
       <mark> record, then no values at 10:00  because  the  ``prior''  value  at  09:30  is  not
       available,  then  the  rate would be reported again at 10:30 and continue every 30 minutes
       until the last reported value at 01:00.

       The presence of <mark> records in a PCP archive log can be established using  pmdumplog(1)
       where a timestamp and the annotation <mark> is used to indicate a <mark> record.


       When  more  than  one  input  archive  set is specified, pmlogextract performs a number of
       checks to ensure the metadata is consistent for metrics appearing in more than one of  the
       input archive sets.  These checks include:

       * metric data type is the same
       * metric semantics are the same
       * metric units are the same
       * metric is either always singular or always has the same instance domain
       * metrics with the same name have the same PMID
       * metrics with the same PMID have the same name

       If  any of these checks fail, pmlogextract reports the details and aborts without creating
       the output archive.

       To address these semantic issues, use pmlogrewrite(1) to translate the input archives into
       equivalent archives with consistent metdadata before using pmlogextract.


       The  preamble metrics (pmcd.pmlogger.archive,, and pmcd.pmlogger.port),
       which are automatically recorded by pmlogger at the start  of  the  archive,  may  not  be
       present  in the archive output by pmlogextract.  These metrics are only relevant while the
       archive is being created, and have no significance once recording has finished.


       All error conditions detected by pmlogextract are reported  on  stderr  with  textual  (if
       sometimes terse) explanation.

       If one of the input archives contains no archive records then an ``empty archive'' warning
       is issued and that archive is skipped.

       Should one of the input archive logs  be  corrupted  (this  can  happen  if  the  pmlogger
       instance  writing  the  log  suddenly  dies), then pmlogextract will detect and report the
       position of the corruption in the file, and any subsequent information from  that  archive
       log will not be processed.

       If any error is detected, pmlogextract will exit with a non-zero status.


       For each of the input and output archive logs, several physical files are used.

            metadata (metric descriptions, instance domains, etc.) for the archive log

            initial  volume  of metrics values (subsequent volumes have suffixes 1, 2, ...) - for
            input these files may have been previously compressed with bzip2(1)  or  gzip(1)  and
            thus may have an additional .bz2 or .gz suffix.

            temporal index to support rapid random access to the other files in the archive log.


       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
       configuration file, as described in pcp.conf(5).

       For environment variables affecting PCP tools, see pmGetOptions(3).


       PCPIntro(1),  pmdumplog(1),   pmlc(1),   pmlogger(1),   pmlogreduce(1),   pmlogrewrite(1),
       pcp.conf(5), pcp.env(5) and PMNS(5).