Class: Stats

Inherits:
Object show all
Defined in:
lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/pg-1.4.5/sample/pg_statistics.rb

Overview

PostgreSQL Stats. Fetch information from pg_stat_* tables. Optionally run in a continuous loop, displaying deltas.

Constant Summary collapse

VERSION = 
%q$Id$

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ Stats

Returns a new instance of Stats.



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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/pg-1.4.5/sample/pg_statistics.rb', line 28

def initialize( opts )
  @opts = opts
  @db   = PG.connect(
    :dbname   => opts.database,
    :host     => opts.host,
    :port     => opts.port,
    :user     => opts.user,
    :password => opts.pass,
    :sslmode  => 'prefer'
  )
  @last = nil
end

Instance Method Details

#get_stats ⇒ Object

Query the database for performance measurements. Returns a hash.



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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/pg-1.4.5/sample/pg_statistics.rb', line 103

def get_stats
  res = @db.exec %Q{
    SELECT
      MAX(stat_db.xact_commit)       AS commits,
      MAX(stat_db.xact_rollback)     AS rollbks,
      MAX(stat_db.blks_read)         AS blksrd,
      MAX(stat_db.blks_hit)          AS blkshit,
      MAX(stat_db.numbackends)       AS bkends,
      SUM(stat_tables.seq_scan)      AS seqscan,
      SUM(stat_tables.seq_tup_read)  AS seqtprd,
      SUM(stat_tables.idx_scan)      AS idxscn,
      SUM(stat_tables.idx_tup_fetch) AS idxtrd,
      SUM(stat_tables.n_tup_ins)     AS ins,
      SUM(stat_tables.n_tup_upd)     AS upd,
      SUM(stat_tables.n_tup_del)     AS del,
      MAX(stat_locks.locks)          AS locks,
      MAX(activity.sess)             AS activeq
    FROM
      pg_stat_database    AS stat_db,
      pg_stat_user_tables AS stat_tables,
      (SELECT COUNT(*) AS locks FROM pg_locks ) AS stat_locks,
      (SELECT COUNT(*) AS sess FROM pg_stat_activity WHERE current_query <> '<IDLE>') AS activity
    WHERE
      stat_db.datname = '%s';
  } % [ @opts.database ]

  return res[0]
end

#run ⇒ Object

Primary loop. Gather statistics and generate deltas.



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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/pg-1.4.5/sample/pg_statistics.rb', line 47

def run
  run_count = 0

  loop do
    current_stat = self.get_stats

    # First run, store and continue
    #
    if @last.nil?
      @last = current_stat
      sleep @opts.interval
      next
    end

    # headers
    #
    if run_count == 0 || run_count % 50 == 0
      puts "%-20s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s" % %w[
        time commits rollbks blksrd blkshit bkends seqscan
        seqtprd idxscn idxtrd ins upd del locks activeq
      ]
    end

    # calculate deltas
    #
    delta = current_stat.inject({}) do |h, pair|
      stat, val = *pair

      if %w[ activeq locks bkends ].include?( stat )
        h[stat] = current_stat[stat].to_i
      else
        h[stat] = current_stat[stat].to_i - @last[stat].to_i
      end

      h
    end
    delta[ 'time' ] = Time.now.strftime('%F %T')

    # new values
    #
    puts "%-20s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s%12s" % [
      delta['time'], delta['commits'], delta['rollbks'], delta['blksrd'],
      delta['blkshit'], delta['bkends'], delta['seqscan'],
      delta['seqtprd'], delta['idxscn'], delta['idxtrd'],
      delta['ins'], delta['upd'], delta['del'], delta['locks'], delta['activeq']
    ]

    @last = current_stat
    run_count += 1
    sleep @opts.interval
  end
end