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  1. MariaDB Server
  2. MDEV-7053

WSREP_STATUS & WSREP_MEMBERSHIP I_S tables

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    Description

      MariaDB Galera server currently dumps many node's status and cluster membership related information to the server logs. The idea behind this task is to make those information available to the user through INFORMATION_SCHEMA. Following is the sample output :

      MariaDB [test]> INSTALL PLUGIN wsrep_status SONAME 'wsrep_status.so';
      		 
      Query OK, 0 rows affected (0.03 sec)
      		 
       
      		 
      MariaDB [test]> INSTALL PLUGIN wsrep_membership SONAME 'wsrep_status.so';
      		 
      Query OK, 0 rows affected (0.16 sec)
      		 
       
      		 
      MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_STATUS;
      		 
      +------------+-------------+----------------+--------------+--------------------------------------+---------------------+-----------------+-----+------------------+
      		 
      | NODE_INDEX | NODE_STATUS | CLUSTER_STATUS | CLUSTER_SIZE | CLUSTER_STATE_UUID                   | CLUSTER_STATE_SEQNO | CLUSTER_CONF_ID | GAP | PROTOCOL_VERSION |
      		 
      +------------+-------------+----------------+--------------+--------------------------------------+---------------------+-----------------+-----+------------------+
      		 
      |          0 | Synced      | Primary        |            3 | 00b0fbad-6e84-11e4-8a8b-376f19ce8ee7 |                   2 |               3 | NO  |                3 |
      		 
      +------------+-------------+----------------+--------------+--------------------------------------+---------------------+-----------------+-----+------------------+
      		 
      1 row in set (0.00 sec)
      		 
       
      		 
      MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_MEMBERSHIP;
      		 
      +-------+--------------------------------------+-------+-----------------+
      		 
      | INDEX | UUID                                 | NAME  | ADDRESS         |
      		 
      +-------+--------------------------------------+-------+-----------------+
      		 
      |     0 | 46da96e3-6e9e-11e4-95a2-f609aa5444b3 | node1 | 10.0.2.15:16000 |
      		 
      |     1 | 5f6bc72a-6e9e-11e4-84ed-57ec6780a3d3 | node2 | 10.0.2.15:16001 |
      		 
      |     2 | 7473fd75-6e9e-11e4-91de-0b541ad91bd0 | node3 | 10.0.2.15:16002 |
      		 
      +-------+--------------------------------------+-------+-----------------+
      		 
      3 rows in set (0.00 sec)
      		 
       

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          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          http://lists.askmonty.org/pipermail/commits/2014-November/006905.html

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - http://lists.askmonty.org/pipermail/commits/2014-November/006905.html
          jplindst Jan Lindström (Inactive) added a comment -

          Ok to push. Just a question, can you query these even in case when
          1) WITH_WSREP is not defined ?
          2) wsrep_on == FALSE ?

          jplindst Jan Lindström (Inactive) added a comment - Ok to push. Just a question, can you query these even in case when 1) WITH_WSREP is not defined ? 2) wsrep_on == FALSE ?
          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          (1) Without WITH_WSREP, this plugin won't get build. Also, if we forcefully try to INSTALL this
          plugin after copying the wsrep_status.so to lib/plugin/, the attempt would fail.

          MariaDB [test]> install plugin wsrep_status soname 'wsrep_status.so';
          		 
          ERROR 1126 (HY000): Can't open shared library '../lib/plugin/wsrep_status.so' (errno: 2, undefined symbol: LOCK_wsrep_config_state)

          (2) When wsrep_on = 0 :

          MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_STATUS;
          		 
          +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+
          		 
          | NODE_INDEX | NODE_STATUS | CLUSTER_SIZE | CLUSTER_UUID                         | PRIMARY | GAP | PROTOCOL_VERSION |
          		 
          +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+
          		 
          |          0 | UNDEFINED   |            0 | 00000000-0000-0000-0000-000000000000 | YES     | NO  |                0 |
          		 
          +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+
          		 
          1 row in set (0.00 sec)
          		 
           
          		 
          MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_MEMBERSHIP;
          		 
          Empty set (0.00 sec)

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - (1) Without WITH_WSREP, this plugin won't get build. Also, if we forcefully try to INSTALL this plugin after copying the wsrep_status.so to lib/plugin/, the attempt would fail. MariaDB [test]> install plugin wsrep_status soname 'wsrep_status.so'; ERROR 1126 (HY000): Can't open shared library '../lib/plugin/wsrep_status.so' (errno: 2, undefined symbol: LOCK_wsrep_config_state) (2) When wsrep_on = 0 : MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_STATUS; +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+ | NODE_INDEX | NODE_STATUS | CLUSTER_SIZE | CLUSTER_UUID | PRIMARY | GAP | PROTOCOL_VERSION | +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+ | 0 | UNDEFINED | 0 | 00000000-0000-0000-0000-000000000000 | YES | NO | 0 | +------------+-------------+--------------+--------------------------------------+---------+-----+------------------+ 1 row in set (0.00 sec)   MariaDB [test]> SELECT * FROM INFORMATION_SCHEMA.WSREP_MEMBERSHIP; Empty set (0.00 sec)
          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          http://lists.askmonty.org/pipermail/commits/2014-November/007039.html

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - http://lists.askmonty.org/pipermail/commits/2014-November/007039.html
          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          https://github.com/MariaDB/server/commit/369c02674cb024ceb1995433913ef2fb32f815ca

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - https://github.com/MariaDB/server/commit/369c02674cb024ceb1995433913ef2fb32f815ca
          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          https://github.com/MariaDB/server/commit/03e0f1f86617c54722cc23f4f5c101d60adfa485

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - https://github.com/MariaDB/server/commit/03e0f1f86617c54722cc23f4f5c101d60adfa485
          joffrey Joffrey MICHAIE (Inactive) added a comment -

          When wsrep is not ready to handle transactions, it is not possible to load the plugin, nor to query the tables.
          Should it be a opened as another feature request, or can we follow up this here ?

          MariaDB [(none)]>  INSTALL SONAME 'wsrep_status';
          		 
          ERROR 1047 (08S01): WSREP has not yet prepared node for application use
          		 
           
          		 
          MariaDB [(none)]>  SELECT * FROM INFORMATION_SCHEMA.WSREP_MEMBERSHIP;
          		 
          ERROR 1047 (08S01): WSREP has not yet prepared node for application use

          joffrey Joffrey MICHAIE (Inactive) added a comment - When wsrep is not ready to handle transactions, it is not possible to load the plugin, nor to query the tables. Should it be a opened as another feature request, or can we follow up this here ? MariaDB [(none)]> INSTALL SONAME 'wsrep_status'; ERROR 1047 (08S01): WSREP has not yet prepared node for application use   MariaDB [(none)]> SELECT * FROM INFORMATION_SCHEMA.WSREP_MEMBERSHIP; ERROR 1047 (08S01): WSREP has not yet prepared node for application use
          nirbhay_c Nirbhay Choubey (Inactive) added a comment -

          Since INSTALL gets replicated, I think having it wait for the node to get ready seem OK. On the other
          hand, detaching I_S queries from wsrep_ready sound like a perfectly valid use case. I have opened
          an FR with upstream.
          https://github.com/codership/mysql-wsrep/issues/36

          nirbhay_c Nirbhay Choubey (Inactive) added a comment - Since INSTALL gets replicated, I think having it wait for the node to get ready seem OK. On the other hand, detaching I_S queries from wsrep_ready sound like a perfectly valid use case. I have opened an FR with upstream. https://github.com/codership/mysql-wsrep/issues/36

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            nirbhay_c Nirbhay Choubey (Inactive)
            nirbhay_c Nirbhay Choubey (Inactive)
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              Resolved:

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