Slow Query Detection¶

pgtail can highlight and track slow queries based on configurable duration thresholds.

Enabling Slow Query Highlighting¶

In tail mode:

slow 100           # Highlight queries > 100ms
slow 500           # Highlight queries > 500ms

Threshold Levels¶

Queries are highlighted based on three severity levels:

Level	Default	Color
Warning	> 100ms	Yellow
Slow	> 500ms	Bold yellow
Critical	> 1000ms	Bold red

Configuring Thresholds¶

Set thresholds in config:

pgtail> set slow.warn 50
pgtail> set slow.error 200
pgtail> set slow.critical 500

Or edit config.toml:

[slow]
warn = 50        # Warning threshold (ms)
error = 200      # Slow threshold (ms)
critical = 500   # Critical threshold (ms)

Query Duration Statistics¶

View statistics for queries observed during tailing:

tail> errors

Shows:

Query Duration Statistics
─────────────────────────
  Queries:  1,234
  Average:  45.2ms

  Percentiles:
    p50:    12.3ms
    p95:    234.5ms
    p99:    567.8ms
    max:    1234.5ms

PostgreSQL Configuration¶

For duration tracking, enable in postgresql.conf:

log_duration = on
# OR
log_min_duration_statement = 0  # Log all with duration

Duration appears in logs as:

LOG:  duration: 234.567 ms
LOG:  duration: 1.234 s  statement: SELECT ...

Notifications for Slow Queries¶

Get notified when queries exceed a threshold:

notify on slow > 500ms

See Notifications for more options.