firebird-qa/tests/bugs/core_0053_test.py

#coding:utf-8
#
# id:           bugs.core_0053
# title:        FIRST 1 vs ORDER DESC vs explicit plan (ODS11)
# decription:   
#                   Test uses pre-created database which has several procedures for analyzing performance by with the help of MON$ tables.
#                   Performance results are gathered in the table STAT_LOG, each odd run will save mon$ counters with "-" sign and next
#                   (even) run will save them with "+" -- see SP_GATHER_STAT.
#                   Aggegation of results is done in the view V_AGG_STAT (negative values relate to start, positive to the end of measure,
#                   difference between them means performance expenses which we want to evaluate).
#                   NOTE. Before each new measure we have to set generator G_GATHER_STAT to zero in order to make it produce proper values
#                   starting with 1 (odd --> NEGATIVE sign for counters). This is done in SP_TRUNCATE_STAT.
#               
#                   :::::::::::::::::::::::::::::::::::::::: NB ::::::::::::::::::::::::::::::::::::
#                   18.08.2020. FB 4.x has incompatible behaviour with all previous versions since build 4.0.0.2131 (06-aug-2020):
#                   statement 'alter sequence <seq_name> restart with 0' changes rdb$generators.rdb$initial_value to -1 thus next call
#                   gen_id(<seq_name>,1) will return 0 (ZERO!) rather than 1. 
#                   See also CORE-6084 and its fix: https://github.com/FirebirdSQL/firebird/commit/23dc0c6297825b2e9006f4d5a2c488702091033d
#                   ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
#                   This is considered as *expected* and is noted in doc/README.incompatibilities.3to4.txt
#               
#                   Because of this, it was decided to change code of SP_TRUNCATE_STAT: instead of 'alter sequence restart...' we do
#                   reset like this: c = gen_id(g_gather_stat, -gen_id(g_gather_stat, 0));
#               
#                   Checked on:
#                       4.0.0.2164 SS: 2.511s.
#                       4.0.0.2164 CS: 2.533s.
#                       3.0.7.33356 SS: 1.495s.
#                       3.0.7.33356 CS: 2.865s.
#                       2.5.9.27150 SC: 0.730s.
#                
# tracker_id:   CORE-0053
# min_versions: ['2.5.1']
# versions:     2.5.1
# qmid:         None

import pytest
from firebird.qa import db_factory, isql_act, Action

# version: 2.5.1
# resources: None

substitutions_1 = []

init_script_1 = """"""

db_1 = db_factory(from_backup='mon-stat-gathering-2_5.fbk', init=init_script_1)

test_script_1 = """
    set list on;

    create or alter procedure gendata as begin end;
    recreate table test (F1 integer, F2 date);
    commit;
      
    set term ^;
    create or alter procedure GenData as
      declare i integer;
    begin
      i= 0;
      while (i < 100000) do begin
        insert into test(F1, F2) values (:i, 'yesterday');
        i= i+1;
      end
    end
    ^
    set term ;^
    commit;
      
    execute procedure gendata;
    commit;

    create desc index test_f1_f2 on test(F1, F2);
    commit;

    execute procedure sp_truncate_stat;
    commit;

    -- #################### MEASURE-1 #################
    
    execute procedure sp_gather_stat; ------- catch statistics BEFORE measured statement(s)
    commit;

    set plan on;
    select first 1 f1
    from test t
    where t.f1=17 and f2 <= 'today'
    plan (T order test_f1_f2)
    order by F1 desc, F2 desc;
    set plan off;

    execute procedure sp_gather_stat; ------- catch statistics BEFORE measured statement(s)
    commit;
 
    -- #################### MEASURE-2 #################


    execute procedure sp_gather_stat; ------- catch statistics BEFORE measured statement(s)
    commit;
  
    set plan on;
    select first 1 f1
    from test t
    where t.f1=17 and f2 <= 'today'
    plan (t order test_f1_f2 index (test_f1_f2))
    order by F1 desc, F2 desc;
    set plan off;

    execute procedure sp_gather_stat; ------- catch statistics BEFORE measured statement(s)
    commit;

    -- #################### ANALYZING RESULTS #################

    set list on;
    select 
        iif( idx_1 / idx_2 > max_ratio, 'PLAN (T ORDER <idx_name>) is slow! Ratio > ' || max_ratio,
             iif( idx_2 / idx_1 > max_ratio, 'PLAN (T ORDER <idx_name> INDEX(<idx_name>)) is slow! Ratio > '|| max_ratio,
                                             'PERFORMANCE IS THE SAME.'
                )
           ) result
    from (
        select 
            cast(min(idx_1) as double precision) as idx_1, 
            cast( min(idx_2)  as double precision) as idx_2,
            3.00 as max_ratio
        from (
            select iif(rowset=1, indexed_reads, null) idx_1, iif(rowset=2, indexed_reads, null) idx_2
            from v_agg_stat
        ) g
    );
    -- Difference of indexed reads that is reported by MON$ tables:
    -- on 2.5 = {5, 5}, on 3.0 = {5, 3} ==> ratio 3.00 should be always enough.
  """

act_1 = isql_act('db_1', test_script_1, substitutions=substitutions_1)

expected_stdout_1 = """
    PLAN (T ORDER TEST_F1_F2)
    F1                              17
    PLAN (T ORDER TEST_F1_F2 INDEX (TEST_F1_F2))
    F1                              17
    RESULT                          PERFORMANCE IS THE SAME.
  """

@pytest.mark.version('>=2.5.1')
def test_1(act_1: Action):
    act_1.expected_stdout = expected_stdout_1
    act_1.execute()
    assert act_1.clean_expected_stdout == act_1.clean_stdout