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https://github.com/FirebirdSQL/firebird-qa.git
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187 lines
6.6 KiB
Python
187 lines
6.6 KiB
Python
#coding:utf-8
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"""
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ID: issue-4625-B
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ISSUE: 4625
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TITLE: Lookup (or scan) in descending index could be very inefficient for some keys
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DESCRIPTION:
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This is ADDITIONAL test for issue in ticket: "Pavel Zotov added a comment - 23/Dec/13 04:02 PM".
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Separate fix was required for this issue, see comments in
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https://sourceforge.net/p/firebird/mailman/message/31785278/
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===
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+ 2013-12-25 10:57 hvlad
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+ M src/jrd/btr.cpp
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+Additional fix for bug CORE-4302 : Lookup (or scan) in descending index could be very inefficient...
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===
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Excessive fetches count reproduced on WI-T3.0.0.30566 (Alpha1 release).
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Current results were checked on Windows (2.5.6.26994, 3.0.0.32484, 4.0.0.138) and POSIX (4.0.0.138)
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NOTES:
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[29.07.2016]
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On 4.0.0.316 number of fetches is ~99 thus new threshold was added for engine = 4.0.
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[18.08.2020]
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FB 4.x has incompatible behaviour with all previous versions since build 4.0.0.2131 (06-aug-2020):
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statement 'alter sequence <seq_name> restart with 0' changes rdb$generators.rdb$initial_value to -1 thus next call
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gen_id(<seq_name>,1) will return 0 (ZERO!) rather than 1.
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See also CORE-6084 and its fix: https://github.com/FirebirdSQL/firebird/commit/23dc0c6297825b2e9006f4d5a2c488702091033d
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This is considered as *expected* and is noted in doc/README.incompatibilities.3to4.txt
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Because of this, it was decided to replace 'alter sequence restart...' with subtraction of two gen values:
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c = gen_id(<g>, -gen_id(<g>, 0)) -- see procedure sp_restart_sequences.
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JIRA: CORE-4302
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FBTEST: bugs.core_4302_addi
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"""
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import pytest
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from firebird.qa import *
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db = db_factory()
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test_script = """
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create or alter procedure sp_restart_sequences as begin end;
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recreate table td(id int, s varchar(50));
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commit;
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set term ^;
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execute block as
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begin
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begin
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execute statement 'drop sequence g';
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when any do begin end
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end
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end^
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set term ;^
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commit;
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create sequence g;
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commit;
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set term ^;
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create or alter procedure sp_restart_sequences as
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declare c bigint;
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begin
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c = gen_id(g, -gen_id(g, 0));
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end
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^
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set term ;^
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commit;
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recreate table t_mon(rn smallint, pg_fetches bigint);
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recreate view v_mon as
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select i.mon$page_fetches as pg_fetches
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from mon$attachments a
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left join mon$io_stats i on a.mon$stat_id=i.mon$stat_id
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where a.mon$attachment_id = current_connection;
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set term ^;
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execute block as
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declare n int = 10000;
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declare m int;
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begin
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'q' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qw' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwe' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwer' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwert' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwerty' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwertyu' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwertyui' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwertyuio' ) returning :m-1 into m;
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m=n; while(m>0) do insert into td(id, s) values( gen_id(g,1), 'qwertyuiop' ) returning :m-1 into m;
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end^ set term ;^
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commit;
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create descending index td_s_des on td(s); commit;
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execute procedure sp_restart_sequences;
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commit;
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insert into t_mon(rn, pg_fetches) values( gen_id(g,1), (select pg_fetches from v_mon));
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set term ^;
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execute block as
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declare c int;
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begin
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select count(*) from rdb$database where exists(select * from td where s='qwertyuiop') into c;
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end
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^
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set term ;^
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commit;
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insert into t_mon(rn, pg_fetches) values( gen_id(g,1), (select pg_fetches from v_mon));
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commit;
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insert into t_mon(rn, pg_fetches) values( gen_id(g,1), (select pg_fetches from v_mon));
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set term ^;
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execute block as
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declare c int;
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begin
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select count(*) from rdb$database where exists(select * from td where s='qwertyuioo') into c; -- note: `o` duplicated at the end of key
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end
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^
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set term ;^
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commit;
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insert into t_mon(rn, pg_fetches) values( gen_id(g,1), (select pg_fetches from v_mon));
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commit;
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set list on;
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select
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rn as measure
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,iif( fetches_diff < max_allowed,
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'OK, less then max_allowed',
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'BAD: '|| fetches_diff ||' - greater then ' || max_allowed || ' for engine = ' || rdb$get_context('SYSTEM','ENGINE_VERSION')
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) as fetches_count
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from (
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select
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rn
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,fetches_at_end - fetches_at_beg as fetches_diff
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,max_for_25
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,max_for_30
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,cast( iif( rdb$get_context('SYSTEM','ENGINE_VERSION') >= '4.0',
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max_for_40,
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iif( rdb$get_context('SYSTEM','ENGINE_VERSION') >= '3.0',
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max_for_30,
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max_for_25
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)
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)
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as int
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) as max_allowed
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from (
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select
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rn
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,max(iif(bg=1, pg_fetches, null)) as fetches_at_beg
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,max(iif(bg=1, null, pg_fetches)) as fetches_at_end
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,140 as max_for_25
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,70 as max_for_30
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,110 as max_for_40 -- 29.07.2016
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-- ^ ####################################################
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-- | # #
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-- +------- # T H R E S H O L D S F O R F E T C H E S #
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-- # #
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-- ####################################################
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from (
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select 1+(rn-1)/2 as rn, mod(rn,2) as bg, pg_fetches
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from t_mon
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)
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group by rn
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)
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)
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order by measure;
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"""
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act = isql_act('db', test_script, substitutions=[('[ ]+', ' ')])
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expected_stdout = """
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MEASURE 1
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FETCHES_COUNT OK, less then max_allowed
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MEASURE 2
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FETCHES_COUNT OK, less then max_allowed
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"""
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@pytest.mark.version('>=3')
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def test_1(act: Action):
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act.expected_stdout = expected_stdout
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act.execute()
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assert act.clean_stdout == act.clean_expected_stdout
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