Transaction issues

OceanBase Database executes transaction requests sent from clients and returns the results to clients. If transaction execution fails or encounters an exception, a transaction error is reported. Common transaction errors fall into two categories: errors thrown to the client during transaction execution and errors discovered through system logs or internal views. This topic summarizes these two categories of errors and common troubleshooting methods to help you identify common issues.

Troubleshooting methods

For transaction issues, troubleshooting methods mainly include querying the transaction status table and searching system logs.

The GV$OB_TRANSACTION_PARTICIPANTS view records the context of participants in uncommitted transactions across the entire cluster, including Leader and Follower nodes. By collecting all participant information of the current transaction, you can construct the execution state of the entire transaction. Key fields:

• TX_TYPE: The value of this field on the leader node is UNDECIDED during transaction execution, and indicates the type of the transaction, such as LOCAL or DISTRIBUTED during transaction commit.

• STATE: the status of the transaction. The value is ACTIVE during transaction execution.

• ACTION: The value of this field on the leader node is START during transaction execution and COMMIT during transaction commit.

For example, the following statement displays the information of transactions in execution:

obclient> select * from gv$ob_transaction_participants\G
*************************** 1. row ***************************
       TENANT_ID: 1002
          SVR_IP: 11.xx.xx.xx
        SVR_PORT: 48274
      SESSION_ID: 3221506881
  SCHEDULER_ADDR: "11.xx.xx.xx:48270"
         TX_TYPE: UNDECIDED
           TX_ID: 752
           LS_ID: 1002
    PARTICIPANTS: NULL
 CTX_CREATE_TIME: 2022-09-21 16:28:46.037405
 TX_EXPIRED_TIME: 2022-09-21 16:43:37.804879
           STATE: ACTIVE
          ACTION: START
PENDING_LOG_SIZE: 57
FLUSHED_LOG_SIZE: 0
            ROLE: LEADER
*************************** 2. row ***************************
       TENANT_ID: 1002
          SVR_IP: 11.xx.xx.xx
        SVR_PORT: 48270
      SESSION_ID: 3221506881
  SCHEDULER_ADDR: "11.xx.xx.xx:48270"
         TX_TYPE: UNDECIDED
           TX_ID: 752
           LS_ID: 1001
    PARTICIPANTS: NULL
 CTX_CREATE_TIME: 2022-09-21 16:28:37.804879
 TX_EXPIRED_TIME: 2022-09-21 16:43:37.804879
           STATE: ACTIVE
          ACTION: START
PENDING_LOG_SIZE: 57
FLUSHED_LOG_SIZE: 0
            ROLE: LEADER

For system logs, you can use the Trace ID to search OBServer logs within the corresponding time range to display all logs on the execution path of a statement. You can also use the transaction ID to search for all logs related to the transaction.