Consider  'delimitedReader' schema of sample project ‘Teak_TafRepoDefault_Files’ located under <Tibco_Home>\adapter\adfiles\6.2\examples.

In the FA example 'delimitedReader', the input file used is 'delimited.txt' in which there are lines from line 1 to line 8 as below:

******
line1: Order, ID41678, 20May2000
line2: Item, GigaWidget, 60, $75
line3: Item, MegaBucket, 48, $125
line4: Customer, Hopkins Associates, ID26490
line5: Order, ID41680, 20May2000
line6: Item, Rt.Clopper, 40, $100
line7: Item, Lt.Clopper, 50, $100
line8: Customer, Jersey WebInovaters, ID46786

******

While using Delta Publishing Mode, there are two points that are needed to be taken care of as below:

1) For every line:

--Each line might be getting written in the input file by other application in any span of time, maybe 10 seconds, maybe 100 seconds, maybe more, whatever, FA does not know, but the delta publishing rule is,
for every line, you have to make each line get written in input file in a span of 3 times pollingIntervals. So we suggest you to tune this proterty to a good point that can make file adapter handle all kinds of writing rates for every line.
--Once one line is delta published, the 3 times rule will be reset, and recounted. So we suggest you to give a proper timeInterval that is applicable for the rate the data is getting written to the input file.

2) For every unbroken message:

--One unbroken msg should get written in the input file in 3 times pollingintervals.
(One unbroken msg means, for example in the above 'delimitedReader' FA example, in the input file 'delimited.txt', as per the Read Schema used, there are two unbroken msgs-->
from line1 to line4 AND
from line5 to line8.

--As per the Read Schema used, line1 to line4 should be one message because the root record is 'Order', and we can see 'Order' again at line5.
But in Delta Publishing Mode, file adapter does not know where the next 'Order' is, because the data is continued to be written in the input file by another application.

--Consider line5 to line8 for instance, in Delta Publishing Mode, File adapter rule is that if there has been no data coming into the input file in 3 times pollingInterval, file adapter will consider line5 to line8 as one unbroken message and publish it out.

--So if FA publishes one unbroken message in Delta Publishing Mode (eg. line 5 to line 8), and after this if there is data getting appended to the last line, for example, if line8 is changed to
"Customer, Jersey WebInovaters, ID46786 fdsfdsfds", this is not allowed.