Subject: Re: [Firebird-devel] [FB-Tracker] Created:
(CORE-5419) Index garbage collection on varchar
column causes server to hang



On 01/11/17 16:19, Vlad Khorsun wrote:
> 11.01.2017 15:09, Alex Peshkoff wrote:
>>
>>>> Could you try fb2.5 (as i did) ?
>>> Will do.
>>>
>> On 2.5 I see approx 50% slowdown when GC is in progress. Same slowdown
>> is present when 'delete from test' is executed.
> Slowdown of what operation ?
>
>> Nothing special for GC, but must say that master seems to miss even this
>> slowdown.
> Master is out of question ;)
>
>> Rather hard to say for sure cause execution time of test
>> connection varies from 0.01 sec to 0.02 sec for 2.5, not more. For
>> master it seems to be almost always 0.01.
> What is done in that test connection ? Could you try to create table
> and insert record into it ?

Run th following test:
for i in `seq 10000`; do echo IIIIIIII $i; time (echo 'create table tt(x
int); commit; insert into tt values(1); commit; drop table tt;'|./isql
todel.fdb) ; sleep 1; done

No activity - 0.8 - 0.9 sec
delete from test - 1.4 - 2.5 sec
select (with GC) - 1.9 - 3.8 sec

I.e. slowdown is obviously present but it's too far from being irresponsive.


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