[MCOL-3800] columnstoreDBWrite -c suspend fails if there are writes to the system Created: 2020-02-17  Updated: 2020-03-13  Resolved: 2020-02-28

Status: Closed
Project: MariaDB ColumnStore
Component/s: ?
Affects Version/s: 1.4.2
Fix Version/s: 1.4.3

Type: Bug Priority: Major
Reporter: Jens Röwekamp (Inactive) Assignee: Gregory Dorman (Inactive)
Resolution: Won't Fix Votes: 0
Labels: None
Environment:

SkySQL - mariadb/skysql-columnstore:1.4.2-2-SKIP-OAM


 Description   

Executing `columnstoreDBWrite -c suspend` to a ColumnStore system which is still executing writes doesn't succeed. The return code of the program further doesn't indicate the failure.

[root@dbaas-1633-mdb-cs-single-0 /]# columnstoreDBWrite -c suspend
 
The following tables are locked:
 
LockID Name         Process  PID  Session  CreationTime           State    DBRoots
 
10     test.tmp2    cpimport 4414 BulkLoad 2020-02-17 01:33:37 PM LOADING  1
 
[root@dbaas-1633-mdb-cs-single-0 /]# echo $?
 
0

It would be better if `columnstoreDBWrite -c suspend` either

  • forces the write only mode (by killing the active queries), or if it
  • blocks all further write queries, waits until the active write queries are finished, and then puts ColumnStore into read only mode.

In case of an error, I would further expect a return code unequal to 0.

 Comments   
Comment by Gregory Dorman (Inactive) [ 2020-02-17 ]

At present we should only do the last part - return code !=0 if it was not able to get the request done. Killing current jobs, or suspending them, is a longer term development.

Comment by David Hall (Inactive) [ 2020-02-20 ]

There is an internal mechanism for setting suspend pending while suppressing new writes. This mechanism is used by "mcsadmin suspendDatabaseWrites". It ought to be leveraged here.

Comment by Gregory Dorman (Inactive) [ 2020-02-28 ]

Workaround is parse the response - accepted and implemented in SSKY

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