SQL statistics for RDS PostgreSQL

For each SQL call and for each second that a query runs, Performance Insights collects SQL statistics. RDS for PostgreSQL collect SQL statistics only at the digest–level. No statistics are shown at the statement-level.

Following, you can find information about digest-level statistics for RDS for PostgreSQL.

Digest statistics for RDS PostgreSQL

To view SQL digest statistics, RDS PostgreSQL must load the pg_stat_statements library. For PostgreSQL DB instances that are compatible with PostgreSQL 11 or later, the database loads this library by default. For PostgreSQL DB instances that are compatible with PostgreSQL 10 or earlier, enable this library manually. To enable it manually, add pg_stat_statements to shared_preload_libraries in the DB parameter group associated with the DB instance. Then reboot your DB instance. For more information, see Parameter groups for Amazon RDS.

Note

Performance Insights can only collect statistics for queries in pg_stat_activity that aren't truncated. By default, PostgreSQL databases truncate queries longer than 1,024 bytes. To increase the query size, change the track_activity_query_size parameter in the DB parameter group associated with your DB instance. When you change this parameter, a DB instance reboot is required.

Per-second digest statistics for RDS PostgreSQL

The following SQL digest statistics are available for PostgreSQL DB instances.

Metric	Unit
db.sql_tokenized.stats.calls_per_sec	Calls per second
db.sql_tokenized.stats.rows_per_sec	Rows per second
db.sql_tokenized.stats.total_time_per_sec	Average active executions per second (AAE)
db.sql_tokenized.stats.shared_blks_hit_per_sec	Block hits per second
db.sql_tokenized.stats.shared_blks_read_per_sec	Block reads per second
db.sql_tokenized.stats.shared_blks_dirtied_per_sec	Blocks dirtied per second
db.sql_tokenized.stats.shared_blks_written_per_sec	Block writes per second
db.sql_tokenized.stats.local_blks_hit_per_sec	Local block hits per second
db.sql_tokenized.stats.local_blks_read_per_sec	Local block reads per second
db.sql_tokenized.stats.local_blks_dirtied_per_sec	Local block dirty per second
db.sql_tokenized.stats.local_blks_written_per_sec	Local block writes per second
db.sql_tokenized.stats.temp_blks_written_per_sec	Temporary writes per second
db.sql_tokenized.stats.temp_blks_read_per_sec	Temporary reads per second
db.sql_tokenized.stats.blk_read_time_per_sec	Average concurrent reads per second
db.sql_tokenized.stats.blk_write_time_per_sec	Average concurrent writes per second

Per-call digest statistics for RDS PostgreSQL

The following metrics provide per call statistics for a SQL statement.

Metric	Unit
db.sql_tokenized.stats.rows_per_call	Rows per call
db.sql_tokenized.stats.avg_latency_per_call	Average latency per call (in ms)
db.sql_tokenized.stats.shared_blks_hit_per_call	Block hits per call
db.sql_tokenized.stats.shared_blks_read_per_call	Block reads per call
db.sql_tokenized.stats.shared_blks_written_per_call	Block writes per call
db.sql_tokenized.stats.shared_blks_dirtied_per_call	Blocks dirtied per call
db.sql_tokenized.stats.local_blks_hit_per_call	Local block hits per call
db.sql_tokenized.stats.local_blks_read_per_call	Local block reads per call
db.sql_tokenized.stats.local_blks_dirtied_per_call	Local block dirty per call
db.sql_tokenized.stats.local_blks_written_per_call	Local block writes per call
db.sql_tokenized.stats.temp_blks_written_per_call	Temporary block writes per call
db.sql_tokenized.stats.temp_blks_read_per_call	Temporary block reads per call
db.sql_tokenized.stats.blk_read_time_per_call	Read time per call (in ms)
db.sql_tokenized.stats.blk_write_time_per_call	Write time per call (in ms)

For more information about these metrics, see pg_stat_statements in the PostgreSQL documentation.