In mrskew, can I calculate human readable timestamps from tim? - oracle

Question

I'm using mrskew by Method-R to analyze Oracle SQL Trace files.
I want to list all database calls similar to the output of calls.rc
But instead of the value of $tim, I'd print a human readable date format.
Raw data (minimal obfuscated):
*** 2020-11-26 10:06:01.867
*** SESSION ID:(1391.49878) 2020-11-26 10:06:01.867
*** CLIENT ID:() 2020-11-26 10:06:01.867
*** SERVICE NAME:(SYS$USERS) 2020-11-26 10:06:01.867
*** MODULE NAME:(JDBC Thin Client) 2020-11-26 10:06:01.867
*** CLIENT DRIVER:(jdbcthin : 12.2.0.1.0) 2020-11-26 10:06:01.867
*** ACTION NAME:() 2020-11-26 10:06:01.867
...
WAIT #0: nam='SQL*Net message from client' ela= 491 driver id=1413697536 #bytes=1 p3=0 obj#=-1 tim=12568091328841
=====================
PARSING IN CURSOR #18446744071522016088 len=71 dep=0 uid=88 oct=7 lid=88 tim=12568091329190 hv=2304270232 ad='61e4d11e0' sqlid='5kpbj024phrws'
/*Begin.Work*/
SELECT ...
END OF STMT
PARSE #18446744071522016088:c=147,e=148,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=957996380,tim=12568091329190
...
EXEC #18446744071522016088:c=683,e=11406,p=0,cr=2,cu=11,mis=0,r=1,dep=0,og=1,plh=957996380,tim=12568091341788
CLOSE #18446744071522016088:c=27,e=27,dep=0,type=1,tim=12568091343665
XCTEND rlbk=0, rd_only=0, tim=12568091343769
Current output (compacted for readability):
END-TIM LINE SQL_ID CALL-NAME STATEMENT-TEXT
-----------------------------------------------------------------------------
12568091.341788 36 5kpbj024phrws EXEC /*Begin.Work*/ SELECT ...
12568091.343769 42 XCTEND
Expected output (please don't cricicise my not correct subsecond calculation):
END-TIME LINE SQL_ID CALL-NAME STATEMENT-TEXT
-----------------------------------------------------------------------
2020-11-26 10:06:01.341788 36 5kpbj024phrws EXEC /*Begin.Work*/ SELECT ...
2020-11-26 10:06:01.343769 42 XCTEND
I assume I can use POSIX:strftime to format the timestamp properly, but I need a way to generate an epoch timestamp from the timestamp at the begin of the tracefile
*** 2020-11-26 10:06:01.867
and then an offset for each $tim relative to this begin of tracefile.
I hope methodr toolset can provide this. It should be easier for me to explain, when (in human readable form) which activity started.

Answer 1

Generating an epoch seconds number from a string date is simple enough. Time::Local has functions to do it.
#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';
use Time::Local 'timelocal_posix';
my $date = '2020-11-26 10:06:01.867';
# Split the date apart
my ($yr, $mon, $day, $hr, $min, $sec, $micro) = split /[- :.]/, $date;
# Note necessary adjustments to month and year
say timelocal_posix($sec, $min, $hr, $day, $mon - 1, $yr - 1900);

Answer 2

With the help of comments by #DaveCross and #CaryMillsap my processing is now:
from the tracefile create an intermediate file similar to
*** 2020-11-26 10:06:01.867
END-TIM LINE SQL_ID CALL-NAME STATEMENT-TEXT
-----------------------------------------------------------------------------
XCTEND tim=12568091341788 e=2 dep=0 36 5kpbj024phrws EXEC /*Begin.Work*/ SELECT ..
XCTEND tim=12568091343769 e=1 dep=0 42 XCTEND
using in calls.rc
sprintf("XCTEND tim=%-20d e=%-5d dep=0 %10d %10d %10d %13s %-40.40s %-.46s", $tim*1000000, $line,($e+$ela)*1000000, $parse_id, $exec_id, $sqlid, "· "x$dep.$name.(scalar(#bind)?"(".join(",",#bind).")":""), "· "x$dep.$sql)
modify the result to have somewhere on top
*** 2020-11-26 10:06:01.867
process this file with mrwhen
get rid of unwantent parts by
sed -E 's/XCTEND t.{37}//'
In more detail it's documented here.