"COPY INTO ..." doesn't work, if executing from 2 processes concurrently. #3758
Last updated: 2016-03-23 15:38:28 +0100
Date: 2015-07-09 13:50:00 +0200
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"COPY INTO ..." doesn't work, if executing from 2 processes in parallel.
ODBC Driver reports
The concurrent (parallel) import of data should work correctly.
Also a parallel create table/drop table or other commands changing the database catalog information.
Steps to Reproduce:
1.Put Data.csv to your home directory on Fedora operating system.
ODBC Driver reports
All data of data.csv should be imported into the 2 tables without error.
In our test script monetBulk.vbs we do a loop to import data.csv 10 times.
Date: 2015-07-09 13:51:30 +0200
Created attachment 338
Date: 2015-07-09 13:56:19 +0200
Created attachment 339
Date: 2015-07-09 13:57:21 +0200
Created attachment 340
Date: 2015-07-09 13:58:37 +0200
Created attachment 341
Date: 2015-07-23 11:56:25 +0200
Created attachment 345
This cmd file reproduces the error situation without importing via COPY INTO, but only execute drop table and create table in concurrent processes.
Date: 2015-07-23 11:58:41 +0200
Created attachment 346
This .vbs file only executes drop table and create table
Date: 2015-07-23 12:01:51 +0200
I have made further analysis on the error situation.
Date: 2015-07-23 12:34:14 +0200
Most probably it not the concurrent copy into into different tables,
Schema statements are (conflicting) transactions on the SQL catalogue.
I'm admittedly not a VBS expert,
Date: 2015-07-27 21:15:40 +0200
Yes you are right in saying that the problem occurs in conflicting schema changing operations.
Your help would be appreciated.
Date: 2015-08-02 12:12:00 +0200
Date: 2015-08-28 13:43:00 +0200
Jul2015 has been released.
Date: 2015-10-17 10:47:18 +0200
Corrupted schema data are still present also with July 2015 release of MonetDB.
When doing concurrent schema operations on the same table, after a while I find no records sys.columns for my table, but in sys.tables there are several records with the same table name! --> corrupted schema
The Problem occurs on simple concurrent create table/drop table operations without importing data.
Mostly server threads of MonetDB abort with segmentation faults. In some cases I observed that the whole dbfarm was out of work after an error.
Even doing concurrent schema operations on different tables also results in error situation and server crashes.
Date: 2016-03-23 15:38:28 +0100
many fixes were done around concurrent schema changes, ie we expect this problem to be fixed (in the to be release sp3)
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