>>Hi there,
>>
>>one functionality of my application ist to receive emails and process them. Sometimes the provider sends these mails twice and I want to prevent that these are processed.
>>I think about saving to values in a table, the first line of the mail and a checksum of the mail body calculates by sys(2007).
>>Before processing the content I would look up these values in the table and if found, skip this mail.
>>Does this make sense or are there better ways?
>>
>>Thanks in advance
>>
>>Thomas
>
>>>As long as you use CRC32, there is a good chance that it will work. At least the chance for a >>doublet is not very high. Possibly you should limit this comparison to a time window, so that a >>years old mail will not have the same checksum by accident. Some Hours?
>
>Unfortunately I have no usable value to because the mail, containing formatted data, there is only a data-value when the mail enters the users inbox.

I>>f you check mail against mail, you need to notify the old CRC somehow. I guess you will not >>un through all mail each times. DBX guy would use a table. There you can put your own >>timestamp, and delete old entries after a while? Each day those older 24h or so.

That's what I'm doing.