Mark, Fantastic info. Since I’m a fan of minifi, that was a great suggestion. I’ve built a minifi before to do something quite similar, so all I need now is access to that fileserver, will give it a go. It IS an on-prem server we own. And this is a one-time operation to process 20 years of research, regulatory and FDA documents, so I can chip away at it over time.
Mike From: Mark Payne <marka...@hotmail.com> Sent: Saturday, March 20, 2021 7:54 AM To: users@nifi.apache.org Subject: Re: [EXTERNAL] speeding up ListFile Mike, Good to know. In short: yes, absolutely, the Windows file server will slow it down that much. You did mention a 100 mb network. Generally, what will be more important is the network latency (because performing the listing and gathering filenames, sizes, etc. can require many tiny requests) and the performance of the server itself (if it’s busy handling tons of other clients, it may be slow to respond). The reason we added the performance metrics in the first place is because we had a user who was upset by the poor performance on a network mounted drive (I think a Windows file server but I’m not sure). Every time they used ‘ls’ or equivalent it was blazing fast. But after instrumenting all of the metrics we were able to find that after doing 50,000 disk operations, even though the typical request was perhaps < 1 ms, some would block for many seconds, even minutes. Not sure if it was a network glitch or the file server itself. That then led us to adding the ability to turn off fetching file attributes, as that made a massive difference for them. I don’t know anything about configuring a Windows file server, so I won’t be help there. But if you own the Windows file server, perhaps this is a situation where it would make sense to run minifi on the file server and have it ship the data to NiFi instead of having NiFi polling. That way, minifi would have local disk access and could then push the data to nifi more quickly. (If this seems like something that would be doable for you, I would recommend you ask for details from someone with more experience in the minifi part of the code base to ensure that all necessary functionality is there, i haven’t looked at minifi in a while. But I think it is). Thanks -Mark On Mar 20, 2021, at 10:41 AM, Mike Sofen <mso...@ansunbiopharma.com<mailto:mso...@ansunbiopharma.com>> wrote: It’s NOT ListFile that is slow, or at least for local file systems. I re-ran a test into a folder tree local to the PC running Nifi (with an SSD). It had 667 files in 129 folders, from which it found 117 matching file types to list (but it still had to read every folder and file). Very VERY fast. 248ms ListFile (.37ms per file) 23 ms UpdateAttribute (add 8 attributes) 12 ms RouteOnAttribute (3 paths) Is it possible that a Windows file server on a 100mb network can slow it down so much? Anyone find a way to speed up remote Windows file access? Mike From: Mike Sofen <mso...@runbox.com<mailto:mso...@runbox.com>> Sent: Friday, March 19, 2021 6:54 PM To: users@nifi.apache.org<mailto:users@nifi.apache.org> Subject: RE: [EXTERNAL] Re: speeding up ListFile Someone help me here: the 157 file listing averaged 46ms, so the total duration SHOULD have been 7.2 seconds, not nearly 4 minutes (227 seconds). What could be going on for the other 220 seconds? Something is amiss. Mike From: Mike Sofen <mso...@ansunbiopharma.com<mailto:mso...@ansunbiopharma.com>> Sent: Friday, March 19, 2021 3:47 PM To: users@nifi.apache.org<mailto:users@nifi.apache.org> Subject: RE: [EXTERNAL] Re: speeding up ListFile Hopes dashed on the rocks of reality...dang. I just retested my folder with 25k files and 11k subfolders (many nesting levels deep – perhaps 15 levels), after clearing state, with the Include File Attributes set to false and it took the same amount of time to produce the listing – about 30 minutes. For some reason my debug setting isn’t writing to the log file (I set debug from within the ListFile processor). But it did pop up that red error square on the processor. So to save time, I re-ran it again for just a deep child folder that had 2 subfolders with a total of 157 files. Here’s my transcription of the debug: “Over the past 227 seconds, For Operation ‘RETRIEVE_NEXT_FILE_FROM_OS’ there were 157 operations performed with an average time of 46.229 milliseconds; STD Deviation = 34ms; Min Time = 0ms; Max Time = 170ms; 12 significant outliers.” To state the obvious, this tiny listing of 157 files averaged more than 1 second per file. That mirrors the speed from my 25k trial which averaged a bit over 1 second per file – that is really slow. What might be going on with the “significant outliers”? Mike From: Olson, Eric <eric.ol...@adm.com<mailto:eric.ol...@adm.com>> Sent: Friday, March 19, 2021 11:45 AM To: users@nifi.apache.org<mailto:users@nifi.apache.org> Subject: RE: [EXTERNAL] Re: speeding up ListFile I’ve observed the same thing. I’m also monitoring directories of large numbers of files and noticed this morning that ListFile took about 30 min to process one directory of about 800,000 files. This is under Linux, but the folder in question is a shared Windows network folder that has been mounted to the Linux machine. (I don’t know how that was done; it’s something my Linux admin set up for me.) I just ran a quick test on a folder with about 75,000 files. ListFile with Include File Attributes set to false took about 10 s to emit the 75,000 FlowFiles. ListFile including file attributes took about 70 s. At the OS level, “ls -lR | wc” takes 2 seconds. Interestingly, in the downstream queue, the two sets of files have the same lineage duration. I guess that’s measured starting at when the ListFile processor was started. From: Mark Payne <marka...@hotmail.com<mailto:marka...@hotmail.com>> Sent: Friday, March 19, 2021 12:08 PM To: users@nifi.apache.org<mailto:users@nifi.apache.org> Subject: [EXTERNAL] Re: speeding up ListFile It’s hard to say without knowing what’s taking so long. Is it simply crawling the directory structure that takes forever? If so, there’s not a lot that can be done, as accessing tons of files just tends to be slow. One way to verify this, on Linux, would be to run: ls -laR I.e., a recursive listing of all files. Not sure what the analogous command would be on Windows. The “Track Performance” property of the processor can be used to understand more about the performance characteristics of the disk access. Set that to true and enable DEBUG logging for the processor. If there are heap concerns, generating a million FlowFiles, then you can set a Record Writer on the processor so that only a single FlowFile gets created. That can then be split up using a tiered approach (SplitRecord to split into 10,000 Record chunks, and then another SplitRecord to split each 10,000 Record chunk into a 1-Record chunk, and then EvaluateJsonPath, for instance, to pull the actual filename into an attribute). I suspect this is not the issue, with that mean heap and given that it’s approximately 1 million files. But it may be a factor. Also, setting the “Include File Attributes” to false can significantly improve performance, especially on a remote network drive, or some specific types of drives/OS’s. Would recommend you play around with the above options to better understand the performance characteristics of your particular environment. Thanks -Mark On Mar 19, 2021, at 12:57 PM, Mike Sofen <mso...@ansunbiopharma.com<mailto:mso...@ansunbiopharma.com>> wrote: I’ve built a document processing solution in Nifi, using the ListFile/FetchFile model hitting a large document repository on our Windows file server. It’s nearly a million files ranging in size from 100kb to 300mb, and files types of pdf, doc/docx, xsl/xslx, pptx, text, xml, rtf, png, tiff and some specialized binary files. The million files is distributed across tens of thousands of folders. The challenge is, for an example subfolder that has 25k files in 11k folders totalling 17gb, it took upwards of 30 minutes for a single ListFile to generate a list and send it downstream to the next processor. It’s running on a PC with the latest gen core i7 with 32gb ram and a 1TB SSD – plenty of horsepower and speed. My bootstrap.cnf has the java.arg.2=-Xms4g and java.arg.3=-Xmx16g. Is there any way to speed up ListFile? Also, is there any way to detect that a file is encrypted? I’m sending these for processing by Tika and Tika generates an error when it receives an encrypted file (we have just a few of those, but enough to be annoying). Mike Sofen Confidentiality Notice: This message may contain confidential or privileged information, or information that is otherwise exempt from disclosure. If you are not the intended recipient, you should promptly delete it and should not disclose, copy or distribute it to others.
