PostgreSQL NRDOT metrics reference

postgresql.backends

Number of backend connections

1

sum (cumulative, int)

—

postgresql.bgwriter.buffers.allocated

Number of allocated buffers

{buffers}

sum (cumulative, int, monotonic)

—

postgresql.bgwriter.buffers.writes

Number of written buffers

{buffers}

sum (cumulative, int, monotonic)

bg_buffer_source (backend, backend_fsync, checkpoints, bgwriter)

postgresql.bgwriter.checkpoint.count

Number of checkpoints performed

{checkpoints}

sum (cumulative, int, monotonic)

bg_checkpoint_type (requested, scheduled)

postgresql.bgwriter.duration

Total time spent on writing and syncing files to disk by checkpoints

ms

sum (cumulative, double, monotonic)

bg_duration_type (sync, write)

postgresql.bgwriter.maxwritten

Number of times the background writer stopped a cleaning scan because it had already written too many buffers

1

sum (cumulative, int, monotonic)

—

postgresql.blocks_read

Number of blocks read

1

sum (cumulative, int, monotonic)

source

postgresql.commits

Number of commits

1

sum (cumulative, int, monotonic)

—

postgresql.connection.max

Maximum number of client connections allowed

{connections}

gauge (int)

—

postgresql.database.count

Number of user databases

{databases}

sum (cumulative, int, non-monotonic)

—

postgresql.db_size

Database disk usage

By

sum (cumulative, int, non-monotonic)

—

postgresql.index.scans

Number of index scans on a table

{scans}

sum (cumulative, int, monotonic)

—

postgresql.index.size

Size of the index on disk

By

gauge (int)

—

postgresql.operations

Number of database row operations

1

sum (cumulative, int, monotonic)

operation (ins, upd, del, hot_upd)

postgresql.replication.data_delay

Amount of data delayed in replication

By

gauge (int)

replication_client

postgresql.rollbacks

Number of rollbacks

1

sum (cumulative, int, monotonic)

—

postgresql.rows

Number of rows in the database

1

sum (cumulative, int, non-monotonic)

state (dead, live)

postgresql.table.count

Number of user tables in a database

{table}

sum (cumulative, int, non-monotonic)

—

postgresql.table.size

Disk space used by a table

By

sum (cumulative, int, non-monotonic)

—

postgresql.table.vacuum.count

Number of times a table was manually vacuumed

{vacuum}

sum (cumulative, int, monotonic)

—

postgresql.wal.age

Age of the oldest WAL file. Requires WAL enabled with at least one replica

s

gauge (int)

—

postgresql.wal.lag

Time between flushing recent WAL locally and receiving notification the standby completed an operation. Requires WAL + at least one replica

s

gauge (int)

wal_operation_lag (flush, replay, write), replication_client

postgresql.database.locks

Number of database locks

{lock}

Database Locks by Mode/Type

—

postgresql.deadlocks

Number of deadlocks

{deadlock}

Deadlocks

—

postgresql.function.calls

Calls made to a function

{call}

Function Calls/min

Requires track_functions=pl|all in postgresql.conf

postgresql.query.conflicts

Queries canceled due to recovery conflicts. Standby-only; zero on primaries

{query}

Query Conflicts

—

postgresql.sequential_scans

Number of sequential scans

{sequential_scan}

Sequential Scans/min

—

postgresql.temp.io

Total data written to temporary files by queries

By

Temp Files & Temp I/O (MB/min)

—

postgresql.temp_files

Number of temporary files

{temp_file}

Temp Files & Temp I/O (MB/min)

—

postgresql.blks_hit

Disk blocks found already in the buffer cache

{blks_hit}

—

postgresql.blks_read

Disk blocks read in this database

{blks_read}

—

postgresql.tup_fetched

Rows fetched by queries in the database

{tup_fetched}

—

postgresql.tup_returned

Rows returned by queries in the database

{tup_returned}

—

postgresql.tup_inserted

Rows inserted by queries in the database

{tup_inserted}

—

postgresql.tup_updated

Rows updated by queries in the database

{tup_updated}

—

postgresql.tup_deleted

Rows deleted by queries in the database

{tup_deleted}

—

postgresql.query.execution.time

Total execution time of SQL statements tracked by pg_stat_statements for the database

s

—

postgresql.wal.delay

Precise replacement for wal.lag, behind the postgresqlreceiver.preciselagmetrics feature gate

s

wal_operation_lag, replication_client

postgresql.vector.search.calls

Vector similarity search executions, grouped by distance function

{search}

postgresql.distance.function.name

postgresql.vector.search.duration

Cumulative execution time of vector searches

s

postgresql.distance.function.name

postgresql.vector.search.rows_returned

Cumulative rows returned by vector searches

{rows}

postgresql.distance.function.name

postgresql.vector.insert.rows

Vectors inserted into pgvector tables

{vectors}

—

postgresql.vector.insert.duration

Cumulative execution time of pgvector inserts

s

—

db.system.name

Name of the database. This is always postgresql

db.query.text

The SQL statement text

db.query.comment_tags / .nr_service_guid

APM-correlation comment tags. For more information, refer to Link your PostgreSQL database with APM

db.query.text.normalized.hash

MD5 of normalized SQL for cross-engine correlation

user.name

User logged into this backend

postgresql.state

Current overall state of the backend

postgresql.pid

Process ID of this backend

postgresql.backend_start

UTC (RFC3339) timestamp the backend/connection started. Stable for the connection's lifetime, unlike postgresql.query_start which changes every query

postgresql.session_duration

Whole seconds since backend start. 0 if backend_start unavailable

postgresql.application_name

Name of the connected application

network.peer.address / network.peer.port

Client IP address / TCP port

postgresql.client_hostname

Reverse-DNS hostname of the client

postgresql.query_start

When the currently active (or last) query started

postgresql.wait_event / .wait_event_type

Wait event name / category, if the backend is currently waiting

postgresql.query_id

Identifier of this backend's most recent query

postgresql.total_exec_time

Query duration in delta milliseconds

postgresql.blocking.pids

Array of PIDs blocking this session. Empty when not blocked

postgresql.blocking.start_time

UTC timestamp when the current lock wait began. Empty when not blocked

postgresql.blocking.wait_duration

Whole seconds waited for a lock. 0 when not blocked

postgresql.blocking.lock.mode / .lock.type / .lock.relation

Lock mode / resource type / relation name being waited on. Empty when not blocked

postgresql.blocking.transaction.start_time

UTC timestamp when the current transaction started. Empty when no active transaction

db.system.name

Name of the database. This is always postgresql

db.query.text

The SQL statement text (normalized, $1/$2 placeholders)

db.query.comment_tags / .nr_service_guid

Same as query_sample. Note: reflects whichever caller ran first — pg_stat_statements hashes queryid from query structure only and freezes the stored text (comments included) at first execution

db.query.text.normalized.hash

MD5 of normalized SQL for cross-engine correlation

postgresql.calls / .rows

Times executed / rows retrieved-affected, delta values

postgresql.shared_blks_dirtied / .hit / .read / .written

Shared block activity, delta values

postgresql.temp_blks_read / .written

Temp block activity, delta values

postgresql.queryid

Hash identifying identical normalized queries

postgresql.rolname

Role that executed the query

postgresql.total_exec_time / .total_plan_time

Total execution / planning time, delta milliseconds

postgresql.query_plan

The EXPLAIN plan for the statement, if obtainable — see EXPLAIN mechanics below