Log file monitoring item supported options and value types

[skupko.sk]

Have item definition:
<key>log[{#STATSFILE},&quot;resource-usage:.*utime=([0-9]+)&quot;,,,,\1]</key>
<value_type>3</value_type> #(Numeric)
<delta>2</delta> #(Simple change)

Example line:
2018-06-04T14:32:24.488793+02:00 server rsyslogd-pstats: resource-usage: utime=12000 stime=16000 maxrss=3864 minflt=429 majflt=0 inblock=0 oublock=328 nvcsw=357

See values as they are seen in logfile, sometimes with lowered value.

2018-06-04 14:44:07	32000
2018-06-04 14:43:37	32000
2018-06-04 14:43:07	31955	32000 in logfile
2018-06-04 14:42:37	31999	32000 in logfile
2018-06-04 14:42:07	31998	32000 in logfile
2018-06-04 14:40:37	27952	28000 in logfile
2018-06-04 14:39:36	28000
2018-06-04 14:37:32	23997	24000 in logfile
2018-06-04 14:36:02	23526	24000 in logfile
2018-06-04 14:35:02	23921	24000 in logfile
2018-06-04 14:34:32	24000

According to documentation only Type, Key, Type of information, Update interval, Log time format options are applicable and others are just ignored?
Is it possible to store values as "Simple change" for log items? If not, then the only possibility to get "simple change" is to create another computed item based on log item?
In Zabbix 3.0.8 all the item configuration options are available even for log item types.

[skupko.sk]

Change the value of 'Store value' to 'As Is' solved the issue with discrepancies.
Just read hint from documentation that log and logrt items should have 'Update interval' set to 1 second. And the Zabbix agent will then send new values once log file was updated.

Still have issue with computed item based on log item.

Log items key (stored As Is with Numeric type):
log[{#STATSFILE},"{#FWDNAME} queue\[DA\]:.* size=([0-9]+)",,,,\1]
log[{#STATSFILE},"{#FWDNAME} queue:.* size=([0-9]+)",,,,\1]

Calculated item key:
rsyslog.diffqueue[{#INST},{#FWDNAME}]
Calculated item formula:
log[{#STATSFILE},"{#FWDNAME} queue:.* size=([0-9]+)",,,,\1].delta(#2)+log[{#STATSFILE},"{#FWDNAME} queue\[DA\]:.* size=([0-9]+)",,,,\1].delta(#2)

Getting error:
Cannot create item: macro "{#STATSFILE}" value is not numeric.

[skupko.sk]

Configuration issue.
The formula of calculated items have specific formatting, not the same like thresholds. Solved by change to:

delta("log[{#STATSFILE},\"{#FWDNAME} queue:.* size=([0-9]+)\",,,,\1]",#2)+delta("log[{#STATSFILE},\"{#FWDNAME} queue\[DA\]:.* size=([0-9]+)\",,,,\1]",#2)