PostgreSQL
PostgreSQL
Plugin: go.d.plugin Module: postgres
Overview
This collector monitors the activity and performance of Postgres servers, collects replication statistics, metrics for each database, table and index, and more.
It establishes a connection to the Postgres instance via a TCP or UNIX socket. To collect metrics for database tables and indexes, it establishes an additional connection for each discovered database.
This collector is supported on all platforms.
This collector supports collecting metrics from multiple instances of this integration, including remote instances.
Default Behavior
Auto-Detection
By default, it detects instances running on localhost by trying to connect as root and netdata using known PostgreSQL TCP and UNIX sockets:
- 127.0.0.1:5432
- /var/run/postgresql/
Limits
Table and index metrics are not collected for databases with more than 50 tables or 250 indexes. These limits can be changed in the configuration file.
Performance Impact
The default configuration for this integration is not expected to impose a significant performance impact on the system.
Setup
Prerequisites
Create netdata user
Create a user with granted pg_monitor
or pg_read_all_stat built-in role.
To create the netdata user with these permissions, execute the following in the psql session, as a user with CREATEROLE privileges:
CREATE USER netdata;
GRANT pg_monitor TO netdata;
After creating the new user, restart the Netdata agent with sudo systemctl restart netdata, or
the appropriate method for your
system.
Configuration
File
The configuration file name for this integration is go.d/postgres.conf.
You can edit the configuration file using the edit-config script from the
Netdata config directory.
cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/postgres.conf
Options
The following options can be defined globally: update_every, autodetection_retry.
| Name | Description | Default | Required |
|---|---|---|---|
| update_every | Data collection frequency. | 5 | False |
| autodetection_retry | Recheck interval in seconds. Zero means no recheck will be scheduled. | 0 | False |
| dsn | Postgres server DSN (Data Source Name). See DSN syntax. | postgres://postgres:postgres@127.0.0.1:5432/postgres | True |
| timeout | Query timeout in seconds. | 2 | False |
| collect_databases_matching | Databases selector. Determines which database metrics will be collected. Syntax is simple patterns. | False | |
| max_db_tables | Maximum number of tables in the database. Table metrics will not be collected for databases that have more tables than max_db_tables. 0 means no limit. | 50 | False |
| max_db_indexes | Maximum number of indexes in the database. Index metrics will not be collected for databases that have more indexes than max_db_indexes. 0 means no limit. | 250 | False |
Examples
TCP socket
An example configuration.
jobs:
- name: local
dsn: 'postgresql://netdata@127.0.0.1:5432/postgres'
Unix socket
An example configuration.
jobs:
- name: local
dsn: 'host=/var/run/postgresql dbname=postgres user=netdata'
Multi-instance
Note: When you define multiple jobs, their names must be unique.
Local and remote instances.
jobs:
- name: local
dsn: 'postgresql://netdata@127.0.0.1:5432/postgres'
- name: remote
dsn: 'postgresql://netdata@203.0.113.0:5432/postgres'
Metrics
Metrics grouped by scope.
The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.
Per PostgreSQL instance
These metrics refer to the entire monitored application.
This scope has no labels.
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.connections_utilization | used | percentage |
| postgres.connections_usage | available, used | connections |
| postgres.connections_state_count | active, idle, idle_in_transaction, idle_in_transaction_aborted, disabled | connections |
| postgres.transactions_duration | a dimension per bucket | transactions/s |
| postgres.queries_duration | a dimension per bucket | queries/s |
| postgres.locks_utilization | used | percentage |
| postgres.checkpoints_rate | scheduled, requested | checkpoints/s |
| postgres.checkpoints_time | write, sync | milliseconds |
| postgres.bgwriter_halts_rate | maxwritten | events/s |
| postgres.buffers_io_rate | checkpoint, backend, bgwriter | B/s |
| postgres.buffers_backend_fsync_rate | fsync | calls/s |
| postgres.buffers_allocated_rate | allocated | B/s |
| postgres.wal_io_rate | write | B/s |
| postgres.wal_files_count | written, recycled | files |
| postgres.wal_archiving_files_count | ready, done | files/s |
| postgres.autovacuum_workers_count | analyze, vacuum_analyze, vacuum, vacuum_freeze, brin_summarize | workers |
| postgres.txid_exhaustion_towards_autovacuum_perc | emergency_autovacuum | percentage |
| postgres.txid_exhaustion_perc | txid_exhaustion | percentage |
| postgres.txid_exhaustion_oldest_txid_num | xid | xid |
| postgres.catalog_relations_count | ordinary_table, index, sequence, toast_table, view, materialized_view, composite_type, foreign_table, partitioned_table, partitioned_index | relations |
| postgres.catalog_relations_size | ordinary_table, index, sequence, toast_table, view, materialized_view, composite_type, foreign_table, partitioned_table, partitioned_index | B |
| postgres.uptime | uptime | seconds |
| postgres.databases_count | databases | databases |
Per repl application
These metrics refer to the replication application.
Labels:
| Label | Description |
|---|---|
| application | application name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.replication_app_wal_lag_size | sent_lag, write_lag, flush_lag, replay_lag | B |
| postgres.replication_app_wal_lag_time | write_lag, flush_lag, replay_lag | seconds |
Per repl slot
These metrics refer to the replication slot.
Labels:
| Label | Description |
|---|---|
| slot | replication slot name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.replication_slot_files_count | wal_keep, pg_replslot_files | files |
Per database
These metrics refer to the database.
Labels:
| Label | Description |
|---|---|
| database | database name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.db_transactions_ratio | committed, rollback | percentage |
| postgres.db_transactions_rate | committed, rollback | transactions/s |
| postgres.db_connections_utilization | used | percentage |
| postgres.db_connections_count | connections | connections |
| postgres.db_cache_io_ratio | miss | percentage |
| postgres.db_io_rate | memory, disk | B/s |
| postgres.db_ops_fetched_rows_ratio | fetched | percentage |
| postgres.db_ops_read_rows_rate | returned, fetched | rows/s |
| postgres.db_ops_write_rows_rate | inserted, deleted, updated | rows/s |
| postgres.db_conflicts_rate | conflicts | queries/s |
| postgres.db_conflicts_reason_rate | tablespace, lock, snapshot, bufferpin, deadlock | queries/s |
| postgres.db_deadlocks_rate | deadlocks | deadlocks/s |
| postgres.db_locks_held_count | access_share, row_share, row_exclusive, share_update, share, share_row_exclusive, exclusive, access_exclusive | locks |
| postgres.db_locks_awaited_count | access_share, row_share, row_exclusive, share_update, share, share_row_exclusive, exclusive, access_exclusive | locks |
| postgres.db_temp_files_created_rate | created | files/s |
| postgres.db_temp_files_io_rate | written | B/s |
| postgres.db_size | size | B |
Per table
These metrics refer to the database table.
Labels:
| Label | Description |
|---|---|
| database | database name |
| schema | schema name |
| table | table name |
| parent_table | parent table name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.table_rows_dead_ratio | dead | percentage |
| postgres.table_rows_count | live, dead | rows |
| postgres.table_ops_rows_rate | inserted, deleted, updated | rows/s |
| postgres.table_ops_rows_hot_ratio | hot | percentage |
| postgres.table_ops_rows_hot_rate | hot | rows/s |
| postgres.table_cache_io_ratio | miss | percentage |
| postgres.table_io_rate | memory, disk | B/s |
| postgres.table_index_cache_io_ratio | miss | percentage |
| postgres.table_index_io_rate | memory, disk | B/s |
| postgres.table_toast_cache_io_ratio | miss | percentage |
| postgres.table_toast_io_rate | memory, disk | B/s |
| postgres.table_toast_index_cache_io_ratio | miss | percentage |
| postgres.table_toast_index_io_rate | memory, disk | B/s |
| postgres.table_scans_rate | index, sequential | scans/s |
| postgres.table_scans_rows_rate | index, sequential | rows/s |
| postgres.table_autovacuum_since_time | time | seconds |
| postgres.table_vacuum_since_time | time | seconds |
| postgres.table_autoanalyze_since_time | time | seconds |
| postgres.table_analyze_since_time | time | seconds |
| postgres.table_null_columns | null | columns |
| postgres.table_size | size | B |
| postgres.table_bloat_size_perc | bloat | percentage |
| postgres.table_bloat_size | bloat | B |
Per index
These metrics refer to the table index.
Labels:
| Label | Description |
|---|---|
| database | database name |
| schema | schema name |
| table | table name |
| parent_table | parent table name |
| index | index name |
Metrics:
| Metric | Dimensions | Unit |
|---|---|---|
| postgres.index_size | size | B |
| postgres.index_bloat_size_perc | bloat | percentage |
| postgres.index_bloat_size | bloat | B |
| postgres.index_usage_status | used, unused | status |
Alerts
The following alerts are available:
| Alert name | On metric | Description |
|---|---|---|
| postgres_total_connection_utilization | postgres.connections_utilization | average total connection utilization over the last minute |
| postgres_acquired_locks_utilization | postgres.locks_utilization | average acquired locks utilization over the last minute |
| postgres_txid_exhaustion_perc | postgres.txid_exhaustion_perc | percent towards TXID wraparound |
| postgres_db_cache_io_ratio | postgres.db_cache_io_ratio | average cache hit ratio in db ${label:database} over the last minute |
| postgres_db_transactions_rollback_ratio | postgres.db_cache_io_ratio | average aborted transactions percentage in db ${label:database} over the last five minutes |
| postgres_db_deadlocks_rate | postgres.db_deadlocks_rate | number of deadlocks detected in db ${label:database} in the last minute |
| postgres_table_cache_io_ratio | postgres.table_cache_io_ratio | average cache hit ratio in db ${label:database} table ${label:table} over the last minute |
| postgres_table_index_cache_io_ratio | postgres.table_index_cache_io_ratio | average index cache hit ratio in db ${label:database} table ${label:table} over the last minute |
| postgres_table_toast_cache_io_ratio | postgres.table_toast_cache_io_ratio | average TOAST hit ratio in db ${label:database} table ${label:table} over the last minute |
| postgres_table_toast_index_cache_io_ratio | postgres.table_toast_index_cache_io_ratio | average index TOAST hit ratio in db ${label:database} table ${label:table} over the last minute |
| postgres_table_bloat_size_perc | postgres.table_bloat_size_perc | bloat size percentage in db ${label:database} table ${label:table} |
| postgres_table_last_autovacuum_time | postgres.table_autovacuum_since_time | time elapsed since db ${label:database} table ${label:table} was vacuumed by the autovacuum daemon |
| postgres_table_last_autoanalyze_time | postgres.table_autoanalyze_since_time | time elapsed since db ${label:database} table ${label:table} was analyzed by the autovacuum daemon |
| postgres_index_bloat_size_perc | postgres.index_bloat_size_perc | bloat size percentage in db ${label:database} table ${label:table} index ${label:index} |
Troubleshooting
Debug Mode
To troubleshoot issues with the postgres collector, run the go.d.plugin with the debug option enabled. The output
should give you clues as to why the collector isn’t working.
-
Navigate to the
plugins.ddirectory, usually at/usr/libexec/netdata/plugins.d/. If that’s not the case on your system, opennetdata.confand look for thepluginssetting under[directories].cd /usr/libexec/netdata/plugins.d/ -
Switch to the
netdatauser.sudo -u netdata -s -
Run the
go.d.pluginto debug the collector:./go.d.plugin -d -m postgres