Include pending request times

Bug #634306 reported by Baron Schwartz
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
tcprstat
New
Undecided
Unassigned

Bug Description

Add a column that indicates the sum of times of sessions that have seen an inbound request, but not an outbound response packet. Title the column 'pending' and make the magic format character 'p'.

This will let us have an idea of how much time currently running queries have accumulated.

Revision history for this message
Baron Schwartz (baron-xaprb) wrote :

Also include a count of pending sessions, with header 'pcount'.

Changed in tcprstat:
milestone: none → 0.9.0
security vulnerability: yes → no
visibility: private → public
Revision history for this message
Baron Schwartz (baron-xaprb) wrote :

I have done more research on this with shell scripting, and based on performance analysis techniques I think we need the following, which is quite similar to /proc/diskstats (http://www.mjmwired.net/kernel/Documentation/iostats.txt):

pending

   The number of sessions for which there has been a request but there is no response yet.

busytime

   The total elapsed time during which there was at least one pending request. This increases while pending is nonzero.

weighted

   The total response time consumed by all requests, including those that are not yet complete.

There is an 'awk' implementation of this in the following script: http://aspersa.googlecode.com/svn/trunk/usl Look at the convert_tcpdump_tabulate() function.

Revision history for this message
Baron Schwartz (baron-xaprb) wrote :

I'm going to close this. After more real-world experience, I can see that this is intractable due to dropped packets. Missed responses to requests will skew things way too much even with a small amount of dropped packets.

To post a comment you must log in.
This report contains Public information  
Everyone can see this information.

Other bug subscribers