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The following tables describe the metrics monitoring memory and CPU usage, including memory compaction triggered by Volt and garbage collection triggered by Java.
Table B.4. Memory, Compaction, and Garbage Collection
| Metrics | Type | Description |
|---|---|---|
| voltdb_compaction_execution_seconds | Histogram | The amount of time it took for compaction to complete. |
| voltdb_compaction_fragmented_percent | Gauge | The current fragmentation percentage. |
| voltdb_compaction_invoked_total | Counter | Number of times compaction was performed. |
| voltdb_compaction_relocated_total | Histogram | The number of tuples relocated during compaction. |
| voltdb_gc_count_total | Counter | The number of times garbage collection was performed. Tags:
|
| voltdb_gc_time_seconds | Counter | Cumulative run time of garbage collection. Tags:
|
| voltdb_memory_indexmemory_bytes | Gauge | The amount of memory in use for storing database indexes. |
| voltdb_memory_javamaxheap_bytes | Gauge | The maximum heap size of the Java runtime environment. |
| voltdb_memory_javaused_bytes | Gauge | The amount of memory allocated by Java and in use by VoltDB. |
| voltdb_memory_nio_total_buffer_count_total | Gauge | An estimate of the number of buffers in the NIO pool. |
| voltdb_memory_nio_total_size_bytes | Gauge | An estimate of the total capacity of all the buffers in the NIO pool. |
| voltdb_memory_nio_used_bytes | Gauge | An estimate of the memory that the Java virtual machine is using for the NIO pool which resides outside the regular Java heap. |
| voltdb_memory_physicalmemory_bytes | Gauge | The total size of physical memory on the server. |
| voltdb_memory_pooledmemory_total | Gauge | The total size of memory allocated for tasks other than database records, indexes, and strings. |
| voltdb_memory_rss_bytes | Gauge | The resident set size. That is, the total amount of memory allocated to the VoltDB processes on the server. |
| voltdb_memory_stringmemory_bytes | Gauge | The amount of memory in use for storing string, binary, and geospatial data that is not stored in-line in the database record. |
| voltdb_memory_tupleallocated_bytes | Gauge | The amount of memory allocated for the storage of database records (including free space). |
| voltdb_memory_tuplecount_total | Gauge | The total number of database records in memory. |
| voltdb_memory_tupledata_bytes | Gauge | The amount of memory in use for storing database records. |
| voltdb_memory_undo_log_size_bytes | Gauge | - |
| voltdb_memory_undo_pool_size_bytes | Gauge | The total size of memory allocated for the undo pool - memory used to store information needed to "undo" database changes if a transaction needs to rollback. |
Table B.5. CPU
| Metrics | Type | Description |
|---|---|---|
| voltdb_cpu_load_percent | Gauge | The percentage of CPU used by the database server process. 0-100. |
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