[MCOL-2217] Document why processes might be in the cold standby or hot standby state Created: 2019-03-06  Updated: 2023-07-02  Resolved: 2023-07-02

Status: Closed
Project: MariaDB ColumnStore
Component/s: N/A
Affects Version/s: 1.2.2
Fix Version/s: Icebox

Type: Task Priority: Major
Reporter: Geoff Montee (Inactive) Assignee: Unassigned
Resolution: Won't Do Votes: 0
Labels: None


 Description   

In a multi-UM configuration, processes such as DDLProc and DMLProc can sometimes show up in the COLD_STANDBY or the HOT_STANDBY state.

For example:

> getSystemInfo
getsysteminfo   Mon Mar  4 14:24:58 2019
 
System cstore-3
 
System and Module statuses
 
Component     Status                       Last Status Change
------------  --------------------------   ------------------------
System        ACTIVE                       Fri Mar  1 20:19:14 2019
 
Module um1    ACTIVE                       Fri Mar  1 20:19:12 2019
Module um2    ACTIVE                       Fri Mar  1 20:19:16 2019
Module pm1    ACTIVE                       Fri Mar  1 20:15:31 2019
Module pm2    ACTIVE                       Fri Mar  1 20:19:15 2019
 
Active Parent OAM Performance Module is 'pm1'
Primary Front-End MariaDB ColumnStore Module is 'um1'
MariaDB ColumnStore Replication Feature is enabled
MariaDB ColumnStore set for Distributed Install
 
 
MariaDB ColumnStore Process statuses
 
Process             Module    Status            Last Status Change        Process ID
------------------  ------    ---------------   ------------------------  ----------
ProcessMonitor      um1       ACTIVE            Fri Mar  1 20:14:57 2019        3838
ServerMonitor       um1       ACTIVE            Fri Mar  1 20:15:29 2019        6033
DBRMWorkerNode      um1       ACTIVE            Fri Mar  1 20:18:24 2019       12918
ExeMgr              um1       ACTIVE            Fri Mar  1 20:18:54 2019       13155
DDLProc             um1       ACTIVE            Fri Mar  1 20:19:02 2019       13210
DMLProc             um1       ACTIVE            Fri Mar  1 20:19:07 2019       13268
mysqld              um1       ACTIVE            Fri Mar  1 20:19:12 2019       13761
 
ProcessMonitor      um2       ACTIVE            Fri Mar  1 20:14:56 2019        3855
ServerMonitor       um2       ACTIVE            Fri Mar  1 20:15:35 2019        5437
DBRMWorkerNode      um2       ACTIVE            Fri Mar  1 20:18:29 2019       10065
ExeMgr              um2       ACTIVE            Fri Mar  1 20:18:58 2019       10302
DDLProc             um2       COLD_STANDBY      Fri Mar  1 20:19:04 2019
DMLProc             um2       COLD_STANDBY      Fri Mar  1 20:19:06 2019
mysqld              um2       ACTIVE            Fri Mar  1 20:19:16 2019       10840
 
ProcessMonitor      pm1       ACTIVE            Fri Mar  1 20:14:39 2019        3835
ProcessManager      pm1       ACTIVE            Fri Mar  1 20:14:45 2019       13482
DBRMControllerNode  pm1       ACTIVE            Fri Mar  1 20:18:22 2019       18294
ServerMonitor       pm1       ACTIVE            Fri Mar  1 20:15:28 2019       14632
DBRMWorkerNode      pm1       ACTIVE            Fri Mar  1 20:18:33 2019       18406
PrimProc            pm1       ACTIVE            Fri Mar  1 20:18:41 2019       18508
WriteEngineServer   pm1       ACTIVE            Fri Mar  1 20:18:48 2019       18589
 
ProcessMonitor      pm2       ACTIVE            Fri Mar  1 20:15:13 2019        3838
ProcessManager      pm2       HOT_STANDBY       Fri Mar  1 20:15:14 2019        5424
DBRMControllerNode  pm2       COLD_STANDBY      Fri Mar  1 20:19:15 2019
ServerMonitor       pm2       ACTIVE            Fri Mar  1 20:15:39 2019        5579
DBRMWorkerNode      pm2       ACTIVE            Fri Mar  1 20:18:37 2019        6065
PrimProc            pm2       ACTIVE            Fri Mar  1 20:18:42 2019        6086
WriteEngineServer   pm2       ACTIVE            Fri Mar  1 20:18:49 2019        6131
 
Active Alarm Counts: Critical = 0, Major = 0, Minor = 0, Warning = 0, Info = 0

It does not seem to be documented anywhere how processes may end up in this state. For example, it is not mentioned on the following pages:

https://mariadb.com/kb/en/library/columnstore-multiple-user-module-guide/

https://mariadb.com/kb/en/library/managing-columnstore-module-configurations/

And the COLD_STANDBY state doesn't even seem to be mentioned here:

https://mariadb.com/kb/en/library/columnstore-system-operations/#viewing-process-status



 Comments   
Comment by John Dutchover [ 2019-03-07 ]

@dleeyh @david.hill@mariadb.com ....Is this related to issue reported in https://jira.mariadb.org/browse/MCOL-1797

Comment by Geoff Montee (Inactive) [ 2019-03-08 ]

jdutch,

Only loosely. This issue is about updating the MariaDB ColumnStore documentation to describe how processes end up in these states.

Comment by Todd Stoffel (Inactive) [ 2023-07-02 ]

The "create date" on this ticket is pre-convergence with MariaDB server. If the issue still exists in a modern version of the engine/plugin please submit a new ticket.

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