This topic describes monitoring metrics related to the cache size within an OceanBase Database tenant. You can specify a statistical range to query statistics about the cache size in a single zone or on a single OBServer of an OceanBase Database tenant.
block_cache
Definition
The block cache size in the specified statistical range.
A block cache is similar to a buffer cache in Oracle Database and is used to store data blocks. To be specific, a block cache stores decompressed microblocks whose sizes swell after decompression.
Description
| Metric | Metric name | Unit |
|---|---|---|
| block_cache | block_cache_size | MB |
Calculation expression
sum(ob_cache_size_bytes{cache_name="user_block_cache",@LABELS}) 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) */ tenant_id, cache_name, cache_size from __all_virtual_kvcache_info where svr_ip = ? and svr_port = ?If you use OceanBase Database V4.0 or later, execute the following statement:
select /* MONITOR_AGENT */ tenant_id, cache_name, cache_size from GV$OB_KVCACHE where svr_ip = ? and svr_port = ?
row_cache
Definition
The row cache size in the specified statistical range.
A row cache stores data rows. After you call the Get or MultiGet method, the data rows returned may be stored in a row cache. This greatly facilitates the query of frequently queried rows, thus significantly improving the query performance.
Description
| Metric | Metric name | Unit |
|---|---|---|
| row_cache | row_cache_size | MB |
Calculation expression
sum(ob_sysstat{stat_id="120008",@LABELS}) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (120008) 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$sysstat where stat_id IN (120008) and (con_id > 1000 or con_id = 1) and class < 1000
plan_cache
Definition
The plan cache size in the specified statistical range.
Description
| Metric | Metric name | Unit |
|---|---|---|
| plan_cache | plan_cache_size | MB |
Calculation expression
sum(ob_plan_cache_memory_bytes{@LABELS}) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ tenant_id, mem_used, access_count, hit_count from v$plan_cache_statIf you use OceanBase Database V4.0 or later, execute the following statement:
select /* MONITOR_AGENT */ tenant_id, mem_used, access_count, hit_count from V$OB_PLAN_CACHE_STAT
clog_cache
Definition
The clog cache size in the specified statistical range.
Description
| Metric | Metric name | Unit |
|---|---|---|
| clog_cache | clog_cache_size | MB |
Calculation expression
sum(ob_sysstat{stat_id="120001",@LABELS}) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (120001) 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$sysstat where stat_id IN (120001) and (con_id > 1000 or con_id = 1) and class < 1000
bloomfilter_cache
Definition
The Bloomfilter cache size in the specified statistical range.
Description
| Metric | Metric name | Unit |
|---|---|---|
| bloomfilter_cache | bloom_filter_cache_size | MB |
Calculation expression
sum(ob_sysstat{stat_id="120009",@LABELS}) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (120009) 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$sysstat where stat_id IN (120009) and (con_id > 1000 or con_id = 1) and class < 1000
location_cache
Definition
The location cache size in the specified statistical range.
Description
| Metric | Metric name | Unit |
|---|---|---|
| location_cache | location_cache_size | MB |
Calculation expression
sum(ob_sysstat{stat_id="120000",@LABELS}) by (@GBLABELS)
SQL statements for metric collection
If you use OceanBase Database of a version earlier than V4.0, execute the following statement:
select /*+ MONITOR_AGENT READ_CONSISTENCY(WEAK) */ con_id tenant_id, stat_id, value from v$sysstat where stat_id IN (120000) 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 (120000) and (con_id > 1000 or con_id = 1) and class < 1000
