Hello, I have an application in Java that uses Spark Streaming 1.2.1 in the following manner:
- Listen to the input directory. - If a new file is copied to that input directory process it. - Process: contact a RESTful web service (running also locally and responsive), send the contents of the file, receive the response from the web service, write the results as a new file into the output directory - batch interval : 30 seconds - checkpoint interval: 150 seconds When I test the application locally with 1 or 2 files, it works perfectly fine as expected. I run it like: spark-submit --class myClass --verbose --master local[4] --deploy-mode client myApp.jar /in file:///out But then I've realized something strange when I copied 20 files to the INPUT directory: Spark Streaming detects all of the files, but it ends up processing *only 16 files*. And the remaining 4 are not processed at all. I've tried it with 19, 18, and then 17 files. Same result, only 16 files end up in the output directory. Then I've tried it by copying 16 files at once to the input directory, and it can process all of the 16 files. That's why I call it magic number 16. When I mean it detects all of the files, I mean that in the logs I see the following lines when I copy 17 files: =============================================================================================================================== 2015-02-16 12:30:51 INFO SpotlightDriver:70 - spark.executor.memory: "1G" 2015-02-16 12:30:51 WARN Utils:71 - Your hostname, emre-ubuntu resolves to a loopback address: 127.0.1.1; using 10.0.2.15 instead (on interface eth0) 2015-02-16 12:30:51 WARN Utils:71 - Set SPARK_LOCAL_IP if you need to bind to another address 2015-02-16 12:30:52 INFO Slf4jLogger:80 - Slf4jLogger started 2015-02-16 12:30:52 WARN NativeCodeLoader:62 - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable 2015-02-16 12:30:53 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Recovered 2 write ahead log files from file:/tmp/receivedBlockMetadata 2015-02-16 12:30:53 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Reading from the logs: file:/tmp/receivedBlockMetadata/log-1424086110599-1424086170599 file:/tmp/receivedBlockMetadata/log-1424086200861-1424086260861 ------------------------------------------- Time: 1424086260000 ms ------------------------------------------- 2015-02-16 12:31:00 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Attempting to clear 0 old log files in file:/tmp/receivedBlockMetadata older than 1424085960000: 2015-02-16 12:31:00 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Cleared log files in file:/tmp/receivedBlockMetadata older than 1424085960000 2015-02-16 12:31:00 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Attempting to clear 0 old log files in file:/tmp/receivedBlockMetadata older than 1424085960000: 2015-02-16 12:31:00 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Cleared log files in file:/tmp/receivedBlockMetadata older than 1424085960000 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:30 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO FileInputFormat:280 - Total input paths to process : 1 2015-02-16 12:31:31 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Attempting to clear 0 old log files in file:/tmp/receivedBlockMetadata older than 1424085990000: 2015-02-16 12:31:31 INFO WriteAheadLogManager for ReceivedBlockHandlerMaster:59 - Cleared log files in file:/tmp/receivedBlockMetadata older than 1424085990000 ------------------------------------------- Time: 1424086290000 ms ------------------------------------------- =============================================================================================================================== In other words it says "Total input paths to process :1" for 17 times. And when I copy 20 files, it says that 20 times. But it always ends up processing 16 files at once and the remaining ones are not processed at all. However, if I first copy 16 files to the input directory, wait for Spark Streaming application to process them (by checking the output directory and seeing that 16 files have been created properly), and then copy the 4 more files, those 4 files are also processed! So now I'm in a weird situation that I have to copy 16 files at maximum at once, wait them to be processed, and only after that copy again 16 files at max, ... otherwise I lose the extra files, in the sense that they are not processed. This is not acceptable in my use-case. I've also checked the parameter spark.streaming.receiver.maxRate and it is INFINITE by default, I've tried setting it to 10 for example, and nothing has changed. Any ideas what might be causing this situation, having a magic number of 16 files at once? -- Emre Sevinç