1PMATRYDELTAINDOM(3)        Library Functions Manual        PMATRYDELTAINDOM(3)
2
3
4

NAME

6       pmaTryDeltaInDom  -  try  to  translate  a physical indom record from a
7       ``full indom'' to a ``delta indom''
8

C SYNOPSIS

10       #include <pcp/pmapi.h>
11       #include <pcp/libpcp.h>
12       #include <pcp/archive.h>
13
14       int pmaTryDeltaInDom(__pmLogCtl *lcp,  __int32_t  **rbuf,  __pmLogInDom
15       *lidp);
16
17       cc ... -lpcp_archive -lpcp
18

CAVEAT

20       This  documentation is intended for internal Performance Co-Pilot (PCP)
21       developer use.
22
23       These interfaces are not part of the PCP APIs that  are  guaranteed  to
24       remain  fixed  across  releases,  and they may not work, or may provide
25       different semantics at some point in the future.
26

DESCRIPTION

28       The input instance domain is passed in as either  a  physical  metadata
29       record  via  rbuf  or  in the ``loaded'' format identified by lidp.  As
30       these are alternate formats for  the  input  instance  domain,  pmaTry‐
31       DeltaInDom demands that exactly one of rbuf and lidp must be NULL, else
32       the return value is -2.
33
34       The input instance domain is on the path to being written  to  the  ar‐
35       chive identified by lcp.
36
37       If  possible,  the instance domain will be converted to the ``delta in‐
38       dom'' format, and the converted instance domain returned  via  rbuf  or
39       lidp  (whichever  is not NULL).  If conversion takes place, any storage
40       assocated with the input instance domain will have been free'd.
41
42       The ``delta indom'' format is only supported for Version 3 archives and
43       it  is  the  caller's  responsibility  to  determine if calling pmaTry‐
44       DeltaInDom is appropriate.
45
46       To determine if the ``delta indom'' format is the most efficient encod‐
47       ing, pmaTryDeltaInDom maintains a per-instance domain cache of the last
48       seen ``full'' instance domain.  To avoid data  corruption,  this  means
49       pmaTryDeltaInDom  first copies the input instance domain.  The copy and
50       the cache are all managed privately by pmaTryDeltaInDom so  the  caller
51       is unaware of this activity.
52
53       The cacheing scheme requires that the caller must call pmaTryDeltaInDom
54       for every instance domain record, independent of  whether  the  ``delta
55       indom'' format is likely to be appropriate.
56

DIAGNOSTICS AND RETURN VALUES

58       In several places, fatal errors will trigger an error message and force
59       the application to exit.
60
61       A return value of -1 indicates that rbuf was not NULL and the  physical
62       record  therein  was  not a TYPE_INDOM (Version 3 ``full'' instance do‐
63       main) record as expected.  A return value of 1 means rbuf or  lidp  has
64       been  rewritten,  and  is now a TYPE_INDOM_DELTA record.  Otherwise the
65       return value is 0.
66

SEE ALSO

68       pmaDeltaInDom(3), PMAPI(3) and pmaUndeltaInDom(3).
69
70
71
72Performance Co-Pilot                  PCP                  PMATRYDELTAINDOM(3)
Impressum