Module: ArJdbc::MSSQL::ExplainSupport

Included in:
ArJdbc::MSSQL
Defined in:
lib/arjdbc/mssql/explain_support.rb

Constant Summary collapse

DISABLED = 
Java::JavaLang::Boolean.getBoolean('arjdbc.mssql.explain_support.disabled')

Instance Method Summary collapse

Instance Method Details

#explain(arel, binds = []) ⇒ Object 



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# File 'lib/arjdbc/mssql/explain_support.rb', line 11

def explain(arel, binds = [])
  return if DISABLED
  sql = to_sql(arel, binds)
  result = with_showplan_on { exec_query(sql, 'EXPLAIN', binds) }
  PrinterTable.new(result).pp
end

#set_showplan_option(enable = true) ⇒ Object (protected) 



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# File 'lib/arjdbc/mssql/explain_support.rb', line 27

def set_showplan_option(enable = true)
  option = 'SHOWPLAN_TEXT'
  execute "SET #{option} #{enable ? 'ON' : 'OFF'}"
rescue Exception => e
  raise ActiveRecord::ActiveRecordError, "#{option} could not be turned" +
        " #{enable ? 'ON' : 'OFF'} (check SHOWPLAN permissions) due : #{e.inspect}"
end

#supports_explain? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/mssql/explain_support.rb', line 9

def supports_explain?; ! DISABLED; end

#with_showplan_on ⇒ Object (protected) 



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# File 'lib/arjdbc/mssql/explain_support.rb', line 20

def with_showplan_on
  set_showplan_option(true)
  yield
ensure
  set_showplan_option(false)
end