Module: ActiveRecord::Trino::Diagnostics

Defined in:
lib/active_record/trino/diagnostics.rb

Overview

Diagnostic helpers for Trino-backed models. Useful when investigating why a Trino-backed query is slow.

Class Method Summary collapse

Class Method Details

.build_result(connection, schema_time, query_time) ⇒ Object 



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# File 'lib/active_record/trino/diagnostics.rb', line 48

def build_result(connection, schema_time, query_time)
  stats = connection.last_query_stats || {}
  {
    schema_time: schema_time,
    query_time: query_time,
    query_id: connection.last_query_id,
    info_uri: connection.last_query_info_uri,
    queued_time_ms: stats[:queued_time_millis],
    elapsed_time_ms: stats[:elapsed_time_millis],
    cpu_time_ms: stats[:cpu_time_millis],
    wall_time_ms: stats[:wall_time_millis],
    state: stats[:state],
  }
end

.profile(model_class) ⇒ Object

Profile a Trino-backed AR model’s first-query latency. Resets the column cache to force a schema re-fetch, times it, then runs a sample SELECT and pulls the per-query breakdown from Trino’s own response.

Returns a Hash with:

:schema_time      Float seconds spent on information_schema.columns
:query_time       Float seconds spent on the sample SELECT (Ruby-side)
:query_id         Trino query_id (cross-reference in the Trino UI)
:info_uri         URL to the query's stats page in the Trino UI
:queued_time_ms   Trino-side: time the query spent queued
:elapsed_time_ms  Trino-side: total wall clock (queued + execution)
:cpu_time_ms      Trino-side: CPU time spent on the query
:wall_time_ms     Trino-side: wall-clock execution time (planning + exec)
:state            "FINISHED" / "FAILED" / etc.

Note: the Trino 351 StatementStats model does not expose planning_time as a discrete field — it is folded into wall_time. If you need the planning slice specifically, subtract wall_time from elapsed_time as a rough approximation.



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# File 'lib/active_record/trino/diagnostics.rb', line 32

def profile(model_class)
  connection = model_class.connection
  model_class.reset_column_information
  schema_time = ::Benchmark.realtime { model_class.columns }

  # Issue the sample SELECT through the adapter directly so it is the
  # last query touching the connection — AR's higher-level paths can
  # fire follow-up bookkeeping queries (SHOW TABLES, etc.) that would
  # otherwise overwrite last_query_* before we read them.
  table = connection.quote_table_name(model_class.table_name)
  sql = "SELECT * FROM #{table} LIMIT 1"
  query_time = ::Benchmark.realtime { connection.exec_query(sql) }

  build_result(connection, schema_time, query_time)
end