This topic describes monitoring metrics related to the time consumed by transaction logs within an OceanBase Database tenant. These metrics are sync_time and write_disk. You can specify a statistical period to query statistics about the time consumed by transaction logs in a single zone or on a single OBServer of an OceanBase Database tenant.
sync_time
Definition
The average time consumed by each transaction log synchronization operation over the network in the specified statistical period.
Description
| Metric | Metric field name | Unit |
|---|---|---|
| sync_time | trans_commit_log_sync_rt | μs |
Calculation expression
sum(rate(ob_sysstat{stat_id="30000",@LABELS}[@INTERVAL])) by (@GBLABELS) / sum(rate(ob_sysstat{stat_id="30001",@LABELS}[@INTERVAL])) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (30000, 30001) and (con_id > 1000 or con_id = 1) and class < 1000If you use OceanBase Database V4.0 or later, execute the following statement:
select /* MONITOR_AGENT */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (30000, 30001) and (con_id > 1000 or con_id = 1) and class < 1000
write_disk
Definition
The average time consumed by each transaction log write to the disk in the specified statistical period.
Description
| Metric | Metric field name | Unit |
|---|---|---|
| write_disk | clog_write_disk_rt | μs |
Calculation expression
sum(rate(ob_sysstat{stat_id="80041",@LABELS}[@INTERVAL])) by (@GBLABELS) / sum(rate(ob_sysstat{stat_id="80040",@LABELS}[@INTERVAL])) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (80040, 80041) and (con_id > 1000 or con_id = 1) and class < 1000If you use OceanBase Database V4.0 or later, execute the following statement:
select /* MONITOR_AGENT */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (80040, 80041) and (con_id > 1000 or con_id = 1) and class < 1000
