Overall status of replication
Column description
| Column name | Description |
|---|---|
| restart_xsn | SN reflected by the remote server that is the target of replication, and the starting point for retransmission when the replication is restarted |
| sender | Whether the sender is running or not |
| receiver | Whether the receiver is running or not |
The name of the replication, IP, sender status, and receiver status can also be checked.
Replication sender information
Column description
| Column name | Description |
|---|---|
| rep_name | Name of replication object |
| peer_ip | IP address of the replication target remote server |
| peer_port | Port number of the replication target remote server |
| Status | It is normal when the current state of sender is 1. / STOP(0), RUN(1), RETRY(2) |
| repl_mode | sender's current replication mode / lazy, eager |
| NET_ERROR_FLAG | network 에러 여부로 0이어야 정상이다. / OK(0), ERROR(1) |
| XSN | sender가 마지막으로 송신한 SN(Serial Number/리두로그일련번호)으로 v$repgap의 REP_SN과 동일 |
The IP, port, network error, and status of the replication sender's remote server can also be checked.
Replication receiver information
Column description
| Column name | Description |
|---|---|
| peer_ip | IP address of the remote server as the subject of replication |
| peer_port | Port number of the remote server that is the subject of replication |
| apply_xsn | SN of the remote server currently being reflected by the receiver |
The IP and port of the remote server of the replication receiver can be checked.
Replication gap
[For Altibase versions earlier than 7]
Column description
| Column name | Description |
|---|---|
| rep_name | Name of replication |
| rep_gap | The degree of unsynchronization is indicated by the interval between rep_last_sn and rep_sn. (I.e. rep_last_sn-rep_sn) |
If the replication gap is increased by a lot, there are things to check.
- Check the network status (operation, failure, if IP or port is blocked by the firewall, etc.)
- Check the remote requirement status (hardware failure, remote DB shutdown, etc.)
- Check the BULK DML operation
In the above case, the replication gap may increase, so it is necessary to check the above cases.
[For Altibase version 7 and above]
Starting from Altibase version 7, the v$repgap view includes a new column called REP_GAP_SIZE, which allows you to check the size of the replication gap in bytes.
Unlike before, the meaning of the REP_GAP column now refers to the size between the most recently logged position by the local server transaction and the current log position being transmitted by the replication sending thread.
The default unit is megabytes (MB), and the value in REP_GAP_SIZE is divided by the REPLICATION_GAP_UNIT property.
Column description
| Column name | Description |
|---|---|
| rep_name | 이중화 이름 |
| rep_gap | The size of the replication gap log files is displayed in the unit set by the property
|
| rep_gap_size | It represents the size of the replication gap log files and is displayed in bytes. |
When the replication gap increases significantly, the following items should be checked:
Network status (e.g., maintenance, failures, or IP/PORT blocking by firewalls)
Remote system status (e.g., hardware failures, remote database shutdowns)
Whether any bulk DML operations are being performed
Since these situations can cause the replication gap to increase, they need to be investigated.