P4DTI issue job000444

TitleP4DTI can generate a lot of conflict email messages very quickly
Assigned userNick Barnes
DescriptionIf a replicator poll sees a conflict, it sends an e-mail to the administrator and the job owner, then proceeds to the next job/issue. If it sees many such conflicts (e.g. because of job000016), it sends many emails. This is bad even if the poll ultimately succeeds. If it fails, it will do exactly the same thing on the next poll. This can turn into a huge email deluge, potentially tens or hundreds of thousands of messages before the administrator can do anything about it.
AnalysisThis turned up because of job000442, and is related to job000443.
It happened again as job000485.
Possible solutions:
1. We could generate summary conflict emails ("the following jobs had conflicts: "), instead of separate emails for each conflict.
2. We could notice that a lot of jobs were conflicting and switch into a different mode in which we disregard conflicts.
3. We could fail any poll which generates N emails (e.g. N = 10). The final email message could say something like "This poll is generating too much email. I'm going to halt it and try again later (at time T)." Combined with the existing exponential backoff, this would mean that an administrator wouldn't get more than 10N to 20N email messages before being able to do something about it.
4. We could only generate a conflict email if the job overwrite actually modifies the job.
How foundcustomer
EvidenceHere is the evidence from job000443:
[1] <http://info.ravenbrook.com/mail/2001/12/19/02-54-20/0.txt>
[2] <http://info.ravenbrook.com/mail/2001/12/19/16-26-34/0.txt>
[3] <http://info.ravenbrook.com/mail/2001/12/19/19-05-25/0.txt>
Observed in1.2.1
Created byNick Barnes
Created on2001-12-20 14:59:39
Last modified byNick Barnes
Last modified on2018-07-05 17:27:54
History2001-12-20 NB Created.
       2018-07-05 NB Suspended because the P4DTI is obsolete.