It should be okay to create a buffer like that. Assuming the FlowFile is small. Typically we try to avoid buffering the content of a FlowFile into memory. But if it’s a reasonable small FlowFile, that’s probably fine.
To be honest, if the issue is intermittent and doesn’t always happen on the same input, it sounds like a threading/concurrency bug. Do you have a buffer or anything like that as a member variable? On Jun 22, 2020, at 10:02 PM, Jason Iannone <bread...@gmail.com<mailto:bread...@gmail.com>> wrote: I'm now thinking its due to how we handled reading the flowfile content into a buffer. Previous: session.read(flowFile, in -> { atomicVessel.set(ByteStreams.toByteArray(in)); }); Current: final byte[] buffer = new byte[(int) flowFile.getSize()]; session.read(flowFile, in -> StreamUtils.fillBuffer(in, buffer, true)); Making this change reduced the occurrences of the data corruption, but we still saw it occur. What I'm now wondering is if sizing the byte array based on flowFile.getSize() is ideal? The contents of the file are raw bytes coming from ConsumeKafka_2_0. Thanks, Jason On Mon, Jun 22, 2020 at 4:51 PM Mark Payne <marka...@hotmail.com<mailto:marka...@hotmail.com>> wrote: Jason, Glad to hear it. This is where the data provenance becomes absolutely invaluable. So now you should be able to trace the lineage of that FlowFile back to the start using data provenance. You can see exactly what it looked like when it was received. If it looks wrong there, the provenance shows exactly where it was received from so you know where to look next. If it looks good on receipt, you can trace the data through the flow and see exactly what the data looked like before and after each processor. And when you see which processor resulted in corruption, you can easily download the data as it looks when it went into the processor to make it easy to re-ingest and test. Thanks -Mark On Jun 22, 2020, at 4:46 PM, Jason Iannone <bread...@gmail.com<mailto:bread...@gmail.com>> wrote: I spoke too soon, and must be the magic of sending an email! We found what appears to be corrupted content and captured the binary, hoping to play it through the code and see what's going on. Thanks, Jason On Mon, Jun 22, 2020 at 4:35 PM Jason Iannone <bread...@gmail.com<mailto:bread...@gmail.com>> wrote: Hey Mark, We hit the issue again, and when digging into the lineage we can see the content is fine coming into MergeContent but is corrupt on output of Join. Any other suggestions? Thanks, Jason On Wed, Jun 10, 2020 at 2:26 PM Mark Payne <marka...@hotmail.com<mailto:marka...@hotmail.com>> wrote: Jason, Control characters should not cause any problem with MergeContent. MergeContent just copies bytes from one stream to another. It’s also worth noting that attributes don’t really come into play here. MergeContent is combining the FlowFile content, so even if it has some weird attributes, those won’t cause a problem in the output content. NiFi stores attributes as a mapping of String to String key/value pairs (i.e., Map<String, String>). So the processor is assuming that if you want to convert a message header to an attribute, that header must be a string. Content in the repository is stored using “slabs” or “blocks.” One processor at a time has the opportunity to write to a file in the content repository. When the processor finishes writing and transfers the FlowFile to the next processor, NiFi keeps track of which file its content was written to, the byte offset where its content starts, and the length of the content. The next time that a processor needs to write to the content of a FlowFile, it may end up appending to that same file on disk, but the FlowFile that the content corresponds to will keep track of the byte offset into the file where its content begins and how many bytes in that file belong to that FlowFile. My recommendation to track this down would be to find a FlowFile that is corrupt, and then use the data provenance feature [1] to view its lineage. Look at the FlowFiles that were joined together by MergeContent and see if any of those is corrupt. Thanks -Mark [1] http://nifi.apache.org/docs/nifi-docs/html/user-guide.html#data_provenance On Jun 10, 2020, at 2:07 PM, Jason Iannone <bread...@gmail.com<mailto:bread...@gmail.com>> wrote: Hey Mark, I was thinking over this more and despite no complaints from Jackson Objectmapper is it possible that hidden and/or control characters are present in the JSON values which would then cause MergeContent to behave this way? I looked over the code and nothing jumped out, but there is something we had to do because of how the publisher is setting kafka header attributes. Some attributes are bytes and not strings converted to bytes, and ConsumeKafka seems to assume that these can always be converted to a String. We had to change the encoding to be ISO8859 due to running into issues with the bytes getting corrupted. I'm also trying to better understand how the content is being stored in the content repository, and whether something is going wrong when writing it out. Thanks, Jason On Tue, Jun 9, 2020 at 8:02 PM Mark Payne <marka...@hotmail.com<mailto:marka...@hotmail.com>> wrote: Hey Jason, Thanks for reaching out. That is definitely odd and not something that I’ve seen or heard about before. Are you certain that the data is not being corrupted upstream of the processor? I ask because the code for the processor that handles writing out the content is pretty straight forward and hasn’t been modified in over 3 years, so I would expect to see it happen often if it were a bug in the MergeContent processor itself. Any chance that you can create a flow template/sample data that recreates the issue? Anything particularly unique about your flow? Thanks -Mark > On Jun 9, 2020, at 6:47 PM, Jason Iannone > <bread...@gmail.com<mailto:bread...@gmail.com>> wrote: > > Hi all, > > Within Nifi 1.10.0 we're seeing unexpected behavior with mergecontent. The > processor is being fed in many flowfiles with individual JSON records. The > records have various field types including a hex-encoded byte[]. We are not > trying to merge JSON records themselves but rather consolidate many flowfiles > into fewer flowfiles. > > What we're seeing is that a random flowfile is split causing the merge file > to be invalid JSON. When running multiple bins we saw the flowfile split > across bins. > > Example > Flowfile 1: {"name": "1", "hexbytes": A10F15B11D14", timestamp: "123456789" } > Flowfile 2: {"name": "2", "hexbytes": A10F15D14B11", timestamp: "123456790" } > Flowfile 3: {"name": "3", "hexbytes": A10F15D14B11", timestamp: "123456790" } > > Merged Result: > {"name": "1", "hexbyters": A10F15B11D14", timestamp: "123456789" } > xbytes": A10F15D14B11", timestamp: "123456790" } > {"name": "3", "hexbytes": A10F15D14B11", timestamp: "123456790" } > {"name": "3", "h > > Mergecontent Configuration: > Concurrent Tasks: 4 > Merge Strategy: Bin-Packing Algorithm > Merge Format: Binary Concatenation > Attribute Strategy: Keep Only Common Attributes > Min. number of entries 1000 > Max number of entries: 20000 > Minimum group size: 10 KB > Maximum number of bins: 5 > Header, Footer, and Demaractor are not set. > > We then backed off the below to reduce min and max entries, bin to 1, and > thread to 1 and still see the same issue. > > Any insights? > > Thanks, > Jason
