Class: Reptile::DeltaMonitor

Inherits:
Object
  • Object
show all
Defined in:
lib/reptile/delta_monitor.rb

Overview

This monitor compares the row counts for each table for each master and slave.

Class Method Summary collapse

Class Method Details

.connection ⇒ Object

Retrieve the active database connection. Nil of none exists.



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# File 'lib/reptile/delta_monitor.rb', line 16

def self.connection
  ActiveRecord::Base.connection
end

.diff(db_name, master_configs, slave_configs) ⇒ Object

Compares the row counts for master tables and slave tables Returns a hash of TABLE_NAME => ROW COUNT DELTAs



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# File 'lib/reptile/delta_monitor.rb', line 22

def self.diff(db_name, master_configs, slave_configs)
  ActiveRecord::Base.establish_connection(slave_configs.merge(user))
  slave_counts = get_table_counts

  ActiveRecord::Base.establish_connection(master_configs.merge(user))
  master_counts = get_table_counts

  deltas= {}
  master_counts.each do |table, master_count|
    if slave_counts[table].nil?
      Log.error "Table '#{table}' exists on master but not on slave."
      next
    end
    delta = master_count.first.to_i - slave_counts[table].first.to_i
    deltas[table] = delta
  end

  print_deltas(db_name, deltas, master_configs)

  deltas
rescue Exception => e
  Log.error "Error: Caught #{e}"
  Log.error "DB Name: #{db_name}"
  Log.error "Master Configs: #{master_configs.inspect}"
  Log.error "Slave Configs: #{slave_configs.inspect}"
  raise e
end

.get_table_counts ⇒ Object

Returns a hash of TABLE_NAME => # Rows for all tables in current db



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# File 'lib/reptile/delta_monitor.rb', line 73

def self.get_table_counts
  tables = get_tables

  tables_w_count = {}
  tables.each do |table|
    connection.execute("SELECT COUNT(*) FROM #{table}").each do |table_count|
      tables_w_count["#{table}"] = table_count
    end
  end
  tables_w_count
end

.get_tables ⇒ Object

Returns an array of strings containing the table names for the current database.



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# File 'lib/reptile/delta_monitor.rb', line 66

def self.get_tables
  tables = []
  connection.execute('SHOW TABLES').each { |row| tables << row }
  tables
end

.print_deltas(db_name, deltas, configs) ⇒ Object

Prints stats about the differences in number of rows between the master and slave



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# File 'lib/reptile/delta_monitor.rb', line 51

def self.print_deltas(db_name, deltas, configs)
  non_zero_deltas = deltas.select{|table, delta| not delta.zero?}
  if non_zero_deltas.size.zero?
    Log.info "Replication counts A-OK for #{db_name} on #{configs['host']} @ #{Time.now}"
  else
    Log.info "Replication Row Count Deltas for #{db_name} on #{configs['host']} @ #{Time.now}"
    Log.info "There #{non_zero_deltas.size > 1 ? 'are' : 'is'} #{non_zero_deltas.size} #{non_zero_deltas.size > 1 ? 'deltas' : 'delta'}"
    non_zero_deltas.each do |table, delta|
      Log.info "  #{table} table: #{delta}" unless delta.zero?
    end
  end
end

.user ⇒ Object

The user settings for a user that has global select privilidgess



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# File 'lib/reptile/delta_monitor.rb', line 10

def self.user
  raise "You need to specify a user!" if @user.nil?
  @user
end

.user=(user_settings) ⇒ Object

Set the user settings for a user that has global SELECT privilidgess



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# File 'lib/reptile/delta_monitor.rb', line 5

def self.user=()
  @user = 
end