Cassandra Performance Service diagnostic table reference 

A complete listing and brief description of Cassandra performance service diagnostic tables.

Note: Table names that contain _snapshot are not related to Cassandra nodetool snapshots; they are snapshots of the data in the last few seconds of activity in the system.

CQL slow log table 

node_slow_log table.

Queries on a node that exceed the cql_slow_log_threshold_ms parameter.

Column Name Data type Description
node_ip inet Node address.
date timestamp Date of entry (MM/DD/YYYY granularity).
start_time timeuuid Start timestamp of query execution.
commands list<text> CQL statements being executed.
duration bigint Execution time in milliseconds.
parameters map<text Not used at this time.
source_ip inet Client address.
table_names set<text> CQL tables touched.
username text User executing query, if authentication is enabled.

CQL system info tables 

key_cache table.

Key cache performance statistics.

Column Name Data type Description
node_ip inet Node address.
cache_capacity bigint Key cache capacity in bytes.
cache_hits bigint Total number of cache hits since startup.
cache_requests bigint Total number of cache requests since startup.
cache_size bigint Current key cache size in bytes.
hit_rate double Ratio of hits to requests since startup.
net_stats table.

Data flow operations repair tasks and more.

Column Name Data type Description
node_ip inet Node address.
commands_completed bigint Total read repair commands completed since startup.
commands_pending int Current number of read repair commands pending.
read_repair_attempted bigint Read repairs attempted since startup.
read_repaired_background bigint Number of read repairs performed asyncronously since startup.
read_repaired_blocking bigint Number of read repairs performed syncronously since startup.
responses_completed bigint Current read repairs completed count.
responses_pending int Current read repair responses pending count.
thread_pool table.

Information on thread pool activity.

Column Name Data type Description
node_ip inet Node address.
pool_name text Thread pool name.
active bigint Currently active tasks.
all_time_blocked bigint Total blocked tasks since startup.
blocked bigint Currently blocked tasks.
completed bigint Total completed tasks since startup.
pending bigint Currently pending tasks.
thread_pool_messages table.

Information about thread pool messages.

Column Name Data type Description
node_ip inet Node address.
message_type text Inter-node message type.
dropped_count int Total count of dropped messages since startup.

Data Resource latency tracking tables 

object_io table.

Per node recent latency metrics by keyspace and table.

Column Name Data type Description
node_ip inet Node address.
keyspace_name text Keyspace name.
table_name text Table name.
last_activity timestamp End of sampling period in which this object was last active.
memory_only boolean DSE memory only table.
read_latency double Mean value in microseconds for all reads during the last active sampling period for this object.
total_reads bigint Count during the last active sampling period for this object.
total_writes bigint Count during the last active sampling period for this object.
write_latency double Mean value in microseconds for all writes during the last active sampling period for this object.
object_read_io_snapshot table.

Per node recent latency metrics by keyspace and table. Ordered by mean read latency.

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean read latency during the last sampling period.
keyspace_name text Keyspace name.
memory_only boolean DSE memory only table.
read_latency double In microseconds during the last sampling period.
table_name text Table name.
total_reads bigint Count during the last sampling period.
total_writes bigint Count during the last sampling period.
write_latency double In microseconds during the last sampling period.
object_write_io_snapshot table.

Per node recent latency metrics by keyspace and table. Ordered by mean write latency. Scale of 0 to 99 (0 is worst).

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean write latency during the last sampling period.
keyspace_name text Keyspace name.
memory_only boolean DSE memory only table.
read_latency double Mean value in microseconds during the active sampling period.
table_name text Table name.
total_reads bigint Count during the last sampling period.
total_writes bigint Count during the last sampling period.
write_latency double Mean value in microseconds during the last sampling period.

Database summary statistics tables 

node_table_snapshot table.

Per node table metrics by keyspace and table.

Column Name Data type Description
node_ip inet Node address.
keyspace_name text Keyspace name.
table_name text Table name.
bf_false_positive_ratio double Bloom filter false positive ratio since startup.
bf_false_positives bigint Bloom filter false positive count since startup.
compression_ratio double Current compression ratio of SSTables.
droppable_tombstone_ratio double Ratio of tombstones older than gc_grace_seconds against total column count in all SSTables.
key_cache_hit_rate double Current key cache hit rate.
live_sstable_count bigint Current SSTable count.
max_row_size bigint Maximum partition size in bytes.
mean_read_latency double In microseconds for this table since startup.
mean_row_size bigint Average partition size in bytes.
mean_write_latency double In microseconds for this table since startup.
memtable_columns_count bigint Approximate number of cells for this table currently resident in memtables.
memtable_size bigint Total size in bytes of memtable data.
memtable_switch_count bigint Number of times memtables have been flushed since startup.
min_row_size bigint Minimum partition size in bytes.
total_data_size bigint Data size on disk in bytes.
total_reads bigint Number of reads since startup.
total_writes bigint Number of writes since startup.
unleveled_sstables bigint Current count of SSTables in level 0 (if using leveled compaction).
table_snapshot table.

Cluster wide lifetime table metrics by keyspace and table. This table aggregates node_table_snapshot from each node in the cluster.

Column Name Data type Description
keyspace_name text Keyspace name.
table_name text Table name.
bf_false_positive_ratio double Bloom filter false positive ratio since startup.
bf_false_positives bigint Bloom filter false positive count since startup.
compression_ratio double Current compression ratio of SSTables.
droppable_tombstone_ratio double Ratio of tombstones older than gc_grace_seconds against total column count in all SSTables.
key_cache_hit_rate double Current key cache hit rate.
live_sstable_count bigint Current SStable count.
max_row_size bigint Maximum partition size in bytes.
mean_read_latency double In microseconds for this table since startup.
mean_row_size bigint Average partition size in bytes.
mean_write_latency double In microseconds for this table since startup.
memtable_columns_count bigint Approximate number of cells for this table currently resident in memtables.
memtable_size bigint Total size in bytes of memtable data.
memtable_switch_count bigint Number of times memtables have been flushed since startup.
min_row_size bigint Minimum partition size in bytes.
total_data_size bigint Data size on disk in bytes.
total_reads bigint Number of reads since startup.
total_writes bigint Number of writes since startup.
unleveled_sstables bigint Current count of SStables in level 0 (if using leveled compaction).
keyspace_snapshot table.

Cluster wide lifetime table metrics, aggregated at the keyspace level (aggregates the data in table_snapshot).

Column Name Data type Description
keyspace_name text Keyspace name.
index_count int Number of secondary indexes.
mean_read_latency double For all tables in the keyspace and all nodes in the cluster since startup.
mean_write_latency double For all tables in the keyspace and all nodes in the cluster since startup.
table_count int Number of tables in the keyspace.
total_data_size bigint Total size in bytes of SSTables for all tables and indexes across all nodes in the cluster.
total_reads bigint For all tables, across all nodes.
total_writes bigint For all tables, across all nodes.

Cluster summary statistics tables 

node_snapshot table.

Per node system metrics.

Column Name Data type Description
node_ip inet Node address.
cms_collection_count bigint CMS garbage collections since startup.
cms_collection_time bigint Total time spent in CMS garbage collection since startup.
commitlog_pending_tasks bigint Current commit log tasks pending.
commitlog_size bigint Total commit log size in bytes.
compactions_completed bigint Number of compactions completed since startup.
compactions_pending int Number of pending compactions.
completed_mutations bigint Total number of mutations performed since startup.
data_owned float Percentage of total data owned by this node.
datacenter text Data center name.
dropped_mutation_ratio double Ratio of dropped to completed mutations since startup.
dropped_mutations bigint Total number of dropped mutations since startup.
flush_sorter_tasks_pending bigint Current number of memtable flush sort tasks pending.
free_space bigint Total free disk space in bytes.
gossip_tasks_pending bigint Current number of gossip tasks pending.
heap_total bigint Total available heap memory in bytes.
heap_used bigint Current heap usage in bytes.
hinted_handoff_pending bigint Current number of hinted handoff tasks pending.
index_data_size bigint Total size in bytes of index column families.
internal_responses_pending bigint Current number of internal response tasks pending.
key_cache_capacity bigint Key cache capacity in bytes.
key_cache_entries bigint Current number of key cache entries.
key_cache_size bigint Current key cache size in bytes.
manual_repair_tasks_pending bigint Current number of manual repair tasks pending.
mean_range_slice_latency double Mean latency in microseconds for range slice operations since startup.
mean_read_latency double Mean latency in microseconds for reads since startup.
mean_write_latency double Mean latency in microseconds for writes since startup.
memtable_post_flushers_pending bigint Current number of memtable post flush tasks pending.
migrations_pending bigint Current number of migration tasks pending.
misc_tasks_pending bigint Current number of misc tasks pending.
parnew_collection_count bigint ParNew garbage collections since startup.
parnew_collection_time bigint Total time spent in ParNew garbage collection since startup.
process_cpu_load double Current CPU load for the DSE process (Linux only).
rack text Rack identifier.
range_slice_timeouts bigint Number of timed out range slice requests since startup.
read_repair_tasks_pending bigint Current number of read repair tasks pending.
read_requests_pending bigint Current read requests pending.
read_timeouts bigint Number of timed out range slice requests since startup.
replicate_on_write_tasks_pending bigint Current.
request_responses_pending bigint Current.
row_cache_capacity bigint Row cache capacity in byte.s
row_cache_entries bigint Current number of row cache entries.
row_cache_size bigint Current row cache size in bytes.
state text Node State (JOINING/LEAVING/MOVING/NORMAL).
storage_capacity bigint Total disk space in bytes.
streams_pending int Current number of pending streams.
table_data_size bigint Total size in bytes of non-index column families.
tokens set<text> Tokens owned by the this node.
total_batches_replayed bigint Total number of batchlog entries replayed since startup
total_node_memory bigint Total available RAM (Linux only).
total_range_slices bigint Total number of range slice operations performed since startup.
total_reads bigint Total number of reads performed since startup.
total_writes bigint Total number of writes performed since startup.
uptime bigint Node uptime in seconds.
write_requests_pending bigint Total number of write tasks pending.
write_timeouts bigint Number of timed out range slice requests since startup.
dc_snapshot table.

Aggregates node_snapshot data at the data center level.

Column Name Data type Description
name text Data center name
compactions_completed bigint Total number of compactions completed since startup by all nodes in the data center.
compactions_pending int Total number of pending compactions on all nodes in the data center.
completed_mutations bigint Total number of mutations performed since startup by all nodes in the data center.
dropped_mutation_ratio double Ratio of dropped to completed mutations since startup across all nodes in the data center.
dropped_mutations bigint Total number of dropped mutations since startup by all nodes in the data center.
flush_sorter_tasks_pending bigint Total number of memtable flush sort tasks pending across all nodes in the data center.
free_space bigint Total free disk space in bytes across all nodes in the data center.
gossip_tasks_pending bigint Total number of gossip tasks pending across all nodes in the data center.
hinted_handoff_pending bigint Total number of hinted handoff tasks pending across all nodes in the data center.
index_data_size bigint Total size in bytes of index column families across all nodes in the data center.
internal_responses_pending bigint number of internal response tasks pending across all nodes in the data center.
key_cache_capacity bigint Total capacity in bytes of key caches across all nodes in the data center.
key_cache_entries bigint Total number of entries in key caches across all nodes in the data center.
key_cache_size bigint Total consumed size in bytes of key caches across all nodes in the data center.
manual_repair_tasks_pending bigint Total number of manual repair tasks pending across all nodes in the data center.
mean_range_slice_latency double Mean latency in microseconds for range slice operations, averaged across all nodes in the data center.
mean_read_latency double Mean latency in microseconds for read operations, averaged across all nodes in the data center.
mean_write_latency double Mean latency in microseconds for write operations, averaged across all nodes in the data center.
memtable_post_flushers_pending bigint Total number of memtable post flush tasks pending across all nodes in the data center.
migrations_pending bigint Total number of migration tasks pending across all nodes in the data center.
misc_tasks_pending bigint Total number of misc tasks pending across all nodes in the data center.
node_count int Total number of live nodes in the data center.
read_repair_tasks_pending bigint Total number of read repair tasks pending across all nodes in the data center.
read_requests_pending bigint Total read requests pending across all nodes in the data center.
replicate_on_write_tasks_pending bigint Total number of counter replicate on write tasks pending across all nodes in the data center.
request_responses_pending bigint Total number of request response tasks pending across all nodes in the data center.
row_cache_capacity bigint Total capacity in bytes of partition caches across all nodes in the data center.
row_cache_entries bigint Total number of row cache entries all nodes in the data center.
row_cache_size bigint Total consumed size in bytes of row caches across all nodes in the data center.
storage_capacity bigint Total disk space in bytes across all nodes in the data center.
streams_pending int number of pending streams across all nodes in the data center.
table_data_size bigint Total size in bytes of non-index column families across all nodes in the data center.
total_batches_replayed bigint Total number of batchlog entries replayed since startup by all nodes in the data center.
total_range_slices bigint Total number of range slice operations performed since startup by all nodes in the data center.
total_reads bigint Total number of read operations performed since startup by all nodes in the data center.
total_writes bigint Total number of write operations performed since startup by all nodes in the data center.
write_requests_pending bigint Total number of write tasks pending across all nodes in the data center.
cluster_snapshot table.

Aggregates node_shapshot data for the whole cluster.

Column Name Data type Description
name text Cluster name.
compactions_completed bigint Total number of compactions completed since startup by all nodes in the cluster.
completed_mutations bigint Total number of mutations performed since startup by all nodes in the cluster.
compactions_pending int Total number of pending compactions on all nodes in the cluster.
datacenters set<text> Data center names.
dropped_mutation_ratio double Ratio of dropped to completed mutations since startup across all nodes in the cluster.
dropped_mutations bigint Total number of dropped mutations since startup by all nodes in the cluster.
flush_sorter_tasks_pending bigint Total number of memtable flush sort tasks pending across all nodes in the cluster.
free_space bigint Total free disk space in bytes across all nodes in the cluster.
gossip_tasks_pending bigint Total number of gossip tasks pending across all nodes in the cluster.
hinted_handoff_pending bigint Total number of hinted handoff tasks pending across all nodes in the cluster.
index_data_size bigint Total size in bytes of index column families across all nodes in the cluster.
internal_responses_pending bigint Number of internal response tasks pending across all nodes in the cluster.
key_cache_capacity bigint Total capacity in bytes of key caches across all nodes in the cluster.
key_cache_entries bigint Total number of entries in key caches across all nodes in the cluster.
key_cache_size bigint Total consumed size in bytes of key caches across all nodes in the cluster.
keyspace_count int Total number of keyspaces defined in schema.
manual_repair_tasks_pending bigint Total number of manual repair tasks pending across all nodes in the cluster.
mean_range_slice_latency double Mean latency in microseconds for range slice operations, averaged across all nodes in the cluster.
mean_read_latency double Mean latency in microseconds for read operations, averaged across all nodes in the cluster.
mean_write_latency double Mean latency in microseconds for write operations, averaged across all nodes in the cluster.
memtable_post_flushers_pending bigint Total number of memtable post flush tasks pending across all nodes in the cluster.
migrations_pending bigint Total number of migration tasks pending across all nodes in the cluster.
misc_tasks_pending bigint Total number of misc tasks pending across all nodes in the cluster.
node_count int Total number of live nodes in the cluster.
read_repair_tasks_pending bigint Total number of read repair tasks pending across all nodes in the cluster.
read_requests_pending bigint Total read requests pending across all nodes in the cluster.
replicate_on_write_tasks_pending bigint Total number of counter replicate on write tasks pending across all nodes in the cluster.
request_responses_pending bigint Total number of request response tasks pending across all nodes in the cluster
row_cache_capacity bigint Total capacity in bytes of partition caches across all nodes in the cluster.
row_cache_entries bigint Total number of row cache entries all nodes in the cluster.
row_cache_size bigint Total consumed size in bytes of row caches across all nodes in the cluster
storage_capacity bigint Total disk space in bytes across all nodes in the cluster.
streams_pending int Number of pending streams across all nodes in the cluster.
table_count int Total number of tables defined in schema.
table_data_size bigint Total size in bytes of non-index column families across all nodes in the cluster.
total_batches_replayed bigint Total number of batchlog entries replayed since startup by all nodes in the cluster.
total_range_slices bigint Total number of read operations performed since startup by all nodes in the cluster.
total_reads bigint Total number of write operations performed since startup by all nodes in the cluster.
total_writes bigint Total number of write tasks pending across all nodes in the cluster.
write_requests_pending bigint Total number of write tasks pending across all nodes in the cluster.

Histogram tables 

read_latency_histograms table.

Read latency histogram data.

Column Name Data type Description
node_ip inet Node address
keyspace_name text Keyspace name
table_name text Table name
histogram_id timestamp Groups rows by the specific histogram they belong to. Rows for the same node, keyspace & table are ordered by this field, to enable date-based filtering
bucket_offset bigint Read latency in microseconds
bucket_count bigint Count of reads where the latency falls in the corresponding bucket
write_latency_histograms table.

Write latency histogram data.

Column Name Data type Description
node_ip inet Node address
keyspace_name text Keyspace name
table_name text Table name
histogram_id timestamp Groups rows by the specific histogram they belong to. Rows for the same node, keyspace & table are ordered by this field, to enable date-based filtering
bucket_offset bigint Write latency in microseconds
bucket_count bigint Count of writes where the latency falls in the corresponding bucket
sstables_per_read_histograms table.

SStables per read histogram data.

Column Name Data type Description
node_ip inet Node address
keyspace_name text Keyspace name
table_name text Table name
histogram_id timestamp Groups rows by the specific histogram they belong to. Rows for the same node, keyspace & table are ordered by this field, to enable date-based filtering
bucket_offset bigint Number of SSTables required to satisfy a read request
bucket_count bigint Count of reads where the number of SSTables read falls in the corresponding bucket
partition_size_histograms table.

Partition size histogram data.

Column Name Data type Description
node_ip inet Node address.
keyspace_name text Keyspace name.
table_name text Table name.
histogram_id timestamp Groups rows by the specific histogram they belong to. Rows for the same node, keyspace & table are ordered by this field, to enable date-based filtering.
bucket_offset bigint Partition size in bytes.
bucket_count bigint Number of partitions where the size falls in the corresponding bucket.
cell_count_histograms table.

Cell count per partition histogram data.

Column Name Data type Description
node_ip inet Node address.
keyspace_name text Keyspace name.
table_name text Table name.
histogram_id timestamp Groups rows by the specific histogram they belong to. Rows for the same node, keyspace, and table are ordered by this field, to enable date-based filtering.
bucket_offset bigint Number of cells in a partition.
bucket_count bigint Number of partitions where the cell count falls in the corresponding bucket.

User and resource latency tracking tables 

user_io table.

Per node, long-lived read/write metrics by client connection and aggregated for all keyspaces and tables.

Column Name Data type Description
node_ip inet Node address.
conn_id text Unique client connection ID.
last_activity timestamp End of sampling period in which this client was last active.
read_latency double In microseconds for the last active sampling period.
total_reads bigint Count during the last active sampling period for this client.
total_writes bigint Count during the last active sampling period for this client.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double In microseconds for the last active sampling period.
user_read_io_snapshot table.

Per node recent read/write metrics by keyspace, table, and client during the most recent sampling period.

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean read latency during the last sampling period.
conn_id text Unique client connection ID.
read_latency double Mean value in microseconds during the last sampling period.
total_reads bigint During the last sampling period.
total_writes bigint During the last sampling period.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last sampling period.
user_write_io_snapshot table.

Per node recent read/write metrics by keyspace, table, and client during the most recent sampling period.

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean write latency during the last sampling period.
conn_id text Unique client connection ID.
read_latency double Mean value in microseconds during the last sampling period.
total_reads bigint During the last sampling period.
total_writes bigint During the last sampling period.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last sampling period.
user_object_io table.

Per node, long-lived read/write metrics by client connection, keyspace and table.

Column Name Data type Description
node_ip inet Node address.
conn_id text Unique client connection ID.
keyspace_name text Keyspace name.
table_name text Table name.
last_activity timestamp End of sampling period in which this client was last active against this object.
read_latency double Mean value in microseconds during the last active sampling period for this object/client.
total_reads bigint During the last active sampling period for this object/client.
total_writes bigint During the last active sampling period for this object/client.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last active sampling period for this object/client.
user_object_write_io_snapshot table.

Per node recent read/write metrics by client, keyspace, and table during the most recent sampling period.

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean write latency during the last sampling period.
conn_id text Unique client connection ID.
keyspace_name text Keyspace name.
read_latency double Mean value in microseconds during the last sampling period.
table_name text Table name.
total_reads bigint During the last sampling period.
total_writes bigint During the last sampling period.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last sampling period.
user_object_read_io_snapshot table.

Per node read/write metrics by client, keyspace, and table during the most recent sampling period. Tracks best-worst latency on a scale of 0 to 99 (0 is worst).

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean read latency during the last sampling period.
conn_id text Unique client connection ID.
keyspace_name text Keyspace name.
read_latency double Mean value in microseconds during the last sampling period.
table_name text Table name.
total_reads bigint During the last sampling period.
total_writes bigint During the last sampling period.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last sampling period.
object_user_io table.

Overview of the I/O activity by user for each table.

Column Name Data type Description
node_ip inet Node address.
keyspace_name text Keyspace name.
table_name text Table name.
conn_id text Unique client connection ID.
last_activity timestamp End of sampling period in which this client connection was last active against this object.
read_latency double Mean value in microseconds during the last active sampling period for this object/client.
total_reads bigint Count during the last active sampling period for this object/client.
total_writes bigint Count during the last active sampling period for this object/client.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last active sampling period for this object/client.
object_user_read_io_snapshot table.

Per node recent read/write metrics by client, keyspace, and table during the most recent sampling period. Tracks best-worst latency on a scale of 0 to 99 (0 is worst).

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean read latency during the last sampling period.
conn_id text Unique client connection ID.
keyspace_name text Keyspace name.
read_latency double Mean value in microseconds during the last active sampling period for this object/client.
table_name text Table name.
total_reads bigint Count during the last active sampling period for this object/client.
total_writes bigint Count during the last active sampling period for this object/client.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last active sampling period for this object/client.
object_user_write_io_snapshot table.

Per node recent read/write metrics by client, keyspace, and table during the most recent sampling period. Tracks best-worst latency on a scale of 0 to 99 (0 is worst).

Column Name Data type Description
node_ip inet Node address.
latency_index int Ranking by mean write latency during the last sampling period.
conn_id text Unique client connection ID.
keyspace_name text Keyspace name.
read_latency double Mean value in microseconds during the last active sampling period for this object/client.
table_name text Table name.
total_reads bigint Count during the last active sampling period for this object/client.
total_writes bigint Count during the last active sampling period for this object/client.
user_ip inet Client origin address.
username text Present if authentication is enabled.
write_latency double Mean value in microseconds during the last active sampling period for this object/client.