mirror of
https://github.com/FirebirdSQL/firebird-qa.git
synced 2025-01-22 21:43:06 +01:00
138 lines
4.8 KiB
Python
138 lines
4.8 KiB
Python
#coding:utf-8
|
|
#
|
|
# id: bugs.core_4302
|
|
# title: Lookup (or scan) in descending index could be very inefficient for some keys
|
|
# decription:
|
|
# ### NB, 16-apr-2016 ###
|
|
# 1. Bug of this ticket was introduced _after_ FB 3.0 Alpha1 release and was fixed 21-dec-2013.
|
|
# I could not reproduce poor statistics (too big value of fetches) on WI-T3.0.0.30566 (Alpha1 release),
|
|
# so temporary build was created based on snapshot of 20-dec-2013 (on POSIX): LI-T3.0.0.30800.
|
|
# This snapshot DOES reproduce problem: number of fetches for val=1 or val=3 is less than 30
|
|
# while for val=2 produces number of fetches more than 210'000.
|
|
# For 2.5.x number of fetches is about 59...67, so common threshold was choosen to value 70.
|
|
# 2. Test was refactored: querying to database 'mon-stat-gathering-N_M.fdb' was removed, all necessary
|
|
# output one may achieve by trivial view (v_mon) that queries mon$io_stats and and table (t_mon) that
|
|
# serves as log.
|
|
#
|
|
# Reproduced on LI-T3.0.0.30800 (snapshot on 20-dec-2013).
|
|
# Current results were checked on Windows (2.5.6.26994, 3.0.0.32484, 4.0.0.138) and POSIX (4.0.0.138)
|
|
#
|
|
# tracker_id: CORE-4302
|
|
# min_versions: ['2.5.3']
|
|
# versions: 2.5.3
|
|
# qmid: None
|
|
|
|
import pytest
|
|
from firebird.qa import db_factory, isql_act, Action
|
|
|
|
# version: 2.5.3
|
|
# resources: None
|
|
|
|
substitutions_1 = []
|
|
|
|
init_script_1 = """"""
|
|
|
|
db_1 = db_factory(sql_dialect=3, init=init_script_1)
|
|
|
|
test_script_1 = """
|
|
recreate table t_mon(rn smallint, pg_fetches bigint);
|
|
|
|
recreate view v_mon as
|
|
select i.mon$page_fetches as pg_fetches
|
|
from mon$attachments a
|
|
left join mon$io_stats i on a.mon$stat_id=i.mon$stat_id
|
|
where a.mon$attachment_id = current_connection;
|
|
|
|
recreate table t1 (id int, val int);
|
|
commit;
|
|
|
|
set term ^;
|
|
execute block as
|
|
declare i int = 0;
|
|
begin
|
|
while (i < 100000) do
|
|
begin
|
|
insert into t1 values (:i, mod(:i, 10));
|
|
i = i + 1;
|
|
end
|
|
end
|
|
^
|
|
set term ;^
|
|
commit;
|
|
|
|
create descending index t1_desc_idx on t1 (val);
|
|
commit;
|
|
|
|
set list on;
|
|
|
|
insert into t_mon(rn, pg_fetches) values( 1, (select pg_fetches from v_mon));
|
|
select * from t1 where val <= 1 order by val desc rows 1;
|
|
commit;
|
|
insert into t_mon(rn, pg_fetches) values( 2, (select pg_fetches from v_mon));
|
|
commit;
|
|
|
|
insert into t_mon(rn, pg_fetches) values( 3, (select pg_fetches from v_mon));
|
|
select * from t1 where val <= 2 order by val desc rows 1;
|
|
commit;
|
|
insert into t_mon(rn, pg_fetches) values( 4, (select pg_fetches from v_mon));
|
|
commit;
|
|
|
|
insert into t_mon(rn, pg_fetches) values( 5, (select pg_fetches from v_mon));
|
|
select * from t1 where val <= 3 order by val desc rows 1;
|
|
commit;
|
|
insert into t_mon(rn, pg_fetches) values( 6, (select pg_fetches from v_mon));
|
|
commit;
|
|
|
|
select
|
|
rn as measure
|
|
,iif( fetches_diff < max_allowed, 'OK, less then ', 'BAD: '|| fetches_diff ||' - greater then ') || max_allowed as fetches_count
|
|
from (
|
|
select
|
|
rn
|
|
,fetches_at_end - fetches_at_beg as fetches_diff
|
|
,70 as max_allowed
|
|
-- ^ ###################################################
|
|
-- | # #
|
|
-- +------- # T H R E S H O L D F O R F E T C H E S #
|
|
-- # #
|
|
-- ###################################################
|
|
from (
|
|
select rn, max(iif(bg=1, pg_fetches, null)) as fetches_at_beg, max(iif(bg=1, null, pg_fetches)) as fetches_at_end
|
|
from (
|
|
select 1+(rn-1)/2 as rn, mod(rn,2) as bg, pg_fetches
|
|
from t_mon
|
|
)
|
|
group by rn
|
|
)
|
|
)
|
|
order by measure;
|
|
"""
|
|
|
|
act_1 = isql_act('db_1', test_script_1, substitutions=substitutions_1)
|
|
|
|
expected_stdout_1 = """
|
|
ID 1
|
|
VAL 1
|
|
ID 2
|
|
VAL 2
|
|
ID 3
|
|
VAL 3
|
|
|
|
MEASURE 1
|
|
FETCHES_COUNT OK, less then 70
|
|
|
|
MEASURE 2
|
|
FETCHES_COUNT OK, less then 70
|
|
|
|
MEASURE 3
|
|
FETCHES_COUNT OK, less then 70
|
|
|
|
"""
|
|
|
|
@pytest.mark.version('>=2.5.3')
|
|
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
|
|
|