I have written a java program when runs a two threads in parallel , copy command in parallel is working fine using batch files but the insert into using batch file is getting hanged , I have given the commands below which I have used in the batch file.

Copy command Batch.

 mclient.bat demo -s "copy into A FROM  'D:\ETL_Source\abcd.csv' using delimiters ',';"

Insert into Batch

mclient.bat demo -s "insert into B select * from A;"

One more problem I am facing is that while running concurrent insert into A select * from B and insert into C select * from D.

I have read a lot about concurrent issue but still I am a bit confuse , my understanding is that for any insert into table monetdb do a db lock and rollback all other queries running in parallel , if this is true then in real time scenario how we can use this db for a DWH , as any time we will have multiple facts and dimensions and for facts we will be doing parallel loads, data volume will be very high.

Please help me out if my understanding is wrong or if I can change some settings to accept parallel insert command.

Please let me know if you need more information from my side for better understanding.

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