1PMGETARCHIVELABEL(3) Library Functions Manual PMGETARCHIVELABEL(3)
2
6 pmGetArchiveLabel, pmGetHighResArchiveLabel - fetch the label record
7 from a set of performance metrics archives
8
10 #include <pcp/pmapi.h>
11 int pmGetArchiveLabel(pmLogLabel *lp);
13 int pmGetHighResArchiveLabel(pmHighResLogLabel *lp);
14 cc ... -lpcp
16
18 Within the framework of the Performance Co-Pilot (PCP), archives of
19 performance metrics values may be accumulated and saved using the pro‐
20 gram pmlogger(1) and the LOGIMPORT(3) programming interface.
21 The routines pmGetArchiveLabel and pmGetHighResArchiveLabel may be used
23 to fetch the label record from a set of archives that has already been
24 opened using pmNewContext(3), or pmDupContext(3), and thereby associ‐
25 ated with the current Performance Metrics Application Programming In‐
26 terface (PMAPI) context.
27 It is recommended that new applications use the high resolution API and
29 existing applications transition to this interface over time.
30 The result returned via the pointer lp is a structure that must be pre-
32 allocated by the caller and has one of the following two formats (de‐
33 fined in pmapi.h).
34 typedef struct {
36 int magic; /* PM_LOG_MAGIC | archive format version no. */
37 pid_t pid; /* PID of logger */
38 struct timespec start; /* start of this archive */
39 char hostname[PM_MAX_HOSTNAMELEN]; /* collection host full name */
40 char timezone[PM_MAX_TIMEZONELEN]; /* generic, squashed $TZ */
41 char zoneinfo[PM_MAX_ZONEINFOLEN]; /* local platform $TZ */
42 } pmHighResLogLabel;
43 typedef struct {
45 int ll_magic; /* PM_LOG_MAGIC | archive format version no. */
46 pid_t ll_pid; /* PID of logger */
47 struct timeval ll_start;/* start of this archive */
48 char ll_hostname[PM_LOG_MAXHOSTLEN]; /* name of collection host */
49 char ll_tz[40]; /* $TZ at collection host */
50 } pmLogLabel;
51 Both forms can be used with either version 2 or version 3 archives.
53 However, the pmHighResLogLabel structure provides the higher resolution
54 start time stored in the newer format, as well as the full timezone and
55 extended length host name fields. For detailed information about the
56 archive on-disk format, refer to LOGARCHIVE(5).
57 For an application using pmGetHighResArchiveLabel, the most useful in‐
59 formation from the archive label is likely to be in the fields start,
60 hostname, timezone, and zoneinfo.
61 The zoneinfo field contains the most detailed timezone information
63 available, and should be used if present (non-zero length string). It
64 will only not be present in the case of version 2 archives - this is a
65 new field added as part of the version 3 format. The timezone field
66 will always be present, however it is the 'squashed' timezone value and
67 in certain situations is not the most accurate timezone.
68 For older applications using pmGetArchiveLabel, the most useful infor‐
70 mation from the archive label is likely to be in the fields ll_start,
71 ll_hostname or ll_tz. Note that the size of the ll_hostname field is
72 PM_LOG_MAXHOSTLEN (64 bytes) which is less than MAXHOSTNAMELEN (see
73 gethostbyname(3)) on some platforms. These semantics are necessary to
74 retain backwards compatibility with the PCP archive file format.
75 Both pmGetArchiveLabel and pmGetHighResArchiveLabel return zero for
77 success.
78
80 PM_ERR_NOCONTEXT
81 the current PMAPI context is either invalid, or not associated
82 with a set of archives
83
85 Environment variables with the prefix PCP_ are used to parameterize the
86 file and directory names used by PCP. On each installation, the file
87 /etc/pcp.conf contains the local values for these variables. The
88 $PCP_CONF variable may be used to specify an alternative configuration
89 file, as described in pcp.conf(5). Values for these variables may be
90 obtained programmatically using the pmGetConfig(3) function.
91
93 pmlogger(1), LOGIMPORT(3), PMAPI(3), pmDupContext(3), pmGetConfig(3),
94 pmNewContext(3), LOGARCHIVE(5), pcp.conf(5) and pcp.env(5).
95Performance Co-Pilot PCP PMGETARCHIVELABEL(3)