Timestamp incompatibility (NiFi's PutSQL)

Question

I'm facing issues with the insertion of timestamps in to a PostgreSQL database using the Nifi PutSQL processor.

More specifically when trying to insert a date in the format '2018-01-31T19:01:09+00:00' in to a timestamptz column I get the following error message:

2018-04-01 19:29:40,091 ERROR [Timer-Driven Process Thread-5] o.apache.nifi.processors.standard.PutSQL PutSQL[id=7997503a-0162-1000-ee81-a0361cad5e0c] Failed to update database for StandardFlowFileRecord[uuid=d02e8b39-e564-4c37-a08a-dab8931e9890,claim=StandardContentClaim [resourceClaim=StandardResourceClaim[id=1522615075930-15, container=default, section=15], offset=11492, length=163],offset=0,name=32836401373126,size=163] due to java.sql.SQLDataException: The value of the sql.args.5.value is '2018-01-31T20:19:35+00:00', which cannot be converted to a timestamp; routing to failure: java.sql.SQLDataException: The value of the sql.args.5.value is '2018-01-31T20:19:35+00:00', which cannot be converted to a timestamp
java.sql.SQLDataException: The value of the sql.args.5.value is '2018-01-31T20:19:35+00:00', which cannot be converted to a timestamp
    at org.apache.nifi.processors.standard.PutSQL.setParameters(PutSQL.java:711)
    at org.apache.nifi.processors.standard.PutSQL.lambda$null$5(PutSQL.java:313)
    at org.apache.nifi.processor.util.pattern.ExceptionHandler.execute(ExceptionHandler.java:127)
    at org.apache.nifi.processors.standard.PutSQL.lambda$new$6(PutSQL.java:311)
    at org.apache.nifi.processors.standard.PutSQL.lambda$new$9(PutSQL.java:354)
    at org.apache.nifi.processor.util.pattern.PutGroup.putFlowFiles(PutGroup.java:91)
    at org.apache.nifi.processor.util.pattern.Put.onTrigger(Put.java:101)
    at org.apache.nifi.processors.standard.PutSQL.lambda$onTrigger$20(PutSQL.java:574)
    at org.apache.nifi.processor.util.pattern.PartialFunctions.onTrigger(PartialFunctions.java:114)
    at org.apache.nifi.processor.util.pattern.RollbackOnFailure.onTrigger(RollbackOnFailure.java:184)
    at org.apache.nifi.processors.standard.PutSQL.onTrigger(PutSQL.java:574)
    at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1122)
    at org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:147)
    at org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:47)
    at org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:128)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.text.ParseException: Unparseable date: "2018-01-31T20:19:35+00:00"
    at java.text.DateFormat.parse(DateFormat.java:366)
    at org.apache.nifi.processors.standard.PutSQL.setParameter(PutSQL.java:911)
    at org.apache.nifi.processors.standard.PutSQL.setParameters(PutSQL.java:707)
    ... 21 common frames omitted

I have tested the insertion of '2018-01-31T19:01:09+00:00' in to the timestamptz column from the command line and it works perfectly. I have tried various alternative formats such as:

• '2018-01-31 19:01:09+00:00'
• '2018-01-31 19:01:09+00'
• '2018-01-31T19:01:09+00'
• '2018-01-31 19:01:09'

They all fail with the same error in Nifi, even though they are all inserted just fine when performing the INSERT from the command line.

Please find a screenshot of my flow attached. Let me know if you need any more details.

To be honest I would prefer to avoid the java conversion all together, as leaving the datetime as a string and inserting it directly in to the Postgres DB works just fine. I have tried forcing this by using an UpdateAttribute processor but that lead to additional errors.

I have come across various questions regarding this topic, but I still don't get what is going on. Most notably:

• PutSql - date format error
• Nifi PutSQL Timestamp/Datetime error cannot be converted error
• '0000-00-00 00:00:00' can not be represented as java.sql.Timestamp error
• Trying To Solve remove the timestamp format conversion error by using "UpdateAttribute" processor i.e. ConvertJSONtoSQL-> UpdateAttribute--> PutSQL

Answer 1

​I resolved this by using an ExecuteStreamCommand processor which calls a python script which converts a JSON line in to it's respective SQL insert statement. The table of interest in this case is reddit_post.

Code of the python script (I'm aware that there is no need for the INSERT argument, but this is there because I plan on adding an UPDATE option later on):

import json
import argparse
import sys

# For command line arguments
parser = argparse.ArgumentParser(description='Converts JSON to respective SQL statement')
parser.add_argument('statement_type', type=str, nargs=1)
parser.add_argument('table_name', type=str, nargs=1)

# Reading the command line arguments
statement_type = parser.parse_args().statement_type[0]
table_name = parser.parse_args().table_name[0]

# Initialize SQL statement 
statement = ''

for line in sys.stdin:
  # Load JSON line
  json_line = json.loads(line)

  # Add table name and SQL syntax
  if statement_type == 'INSERT':
    statement += 'INSERT INTO {} '.format(table_name)

  # Add table parameters and SQL syntax
  statement += '({}) '.format(', '.join(json_line.keys()))

  # Add table values and SQL syntax
  # Note that strings are formatted with single quotes, other data types are converted to strings (for the join method)
  statement += "VALUES ({});".format(', '.join("'{0}'".format(value.replace("'", "''")) if type(value) == str else str(value) for value in json_line.values()))

  # Send statement to stdout
  print(statement)
​

Configuration of ExecuteStreamCommand (Note that Argument Delimeter is set to a single space):

Flow snippet:

I hope this can help someone that came across a similar issue. If you have any advice on how to improve the script, flow, or anything else please don't hesitate to let me know!