Re: Locking B-tree leafs immediately in exclusive mode - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Locking B-tree leafs immediately in exclusive mode
Date
Msg-id CANP8+j+oCBhHYHTj7h4bB-zrW2YT-Eu_95GMh=O6TT5YjDYJcg@mail.gmail.com
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In response to RE: Locking B-tree leafs immediately in exclusive mode  ("Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>)
Responses RE: Locking B-tree leafs immediately in exclusive mode  ("Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>)
List pgsql-hackers
On 9 July 2018 at 04:18, Imai, Yoshikazu <imai.yoshikazu@jp.fujitsu.com> wrote:

>> # script_ordered.sql
>> INSERT INTO ordered (value) VALUES ('abcdefghijklmnoprsqtuvwxyz');
>>
>> # script_unordered.sql
>> \set i random(1, 1000000)
>> INSERT INTO unordered VALUES (:i, 'abcdefghijklmnoprsqtuvwxyz');


>> # results
>> ordered, master: 157473 TPS
>> ordered, patched 231374 TPS
>> unordered, master: 232372 TPS
>> unordered, patched: 232535 TPS
>
> # my results
> ordered, master:     186045 TPS
> ordered, patched:    265842 TPS
> unordered, master:   313011 TPS
> unordered, patched:  309636 TPS
>
> I confirmed that this patch improves ordered insertion.

Looks good

Please can you check insertion with the index on 2 keys
1st key has 10,000 values
2nd key has monotonically increasing value from last 1st key value

So each session picks one 1st key value
Then each new INSERTion is a higher value of 2nd key
so 1,1, then 1,2 then 1,3 etc

Probably easier to do this with a table like this

CREATE UNLOGGED TABLE ordered2 (id integer, logdate timestamp default
now(), value text not null, primary key (id, logdate));

# script_ordered2.sql
\set i random(1, 10000)
INSERT INTO ordered2 (id, value) VALUES (:i, 'abcdefghijklmnoprsqtuvwxyz');

Thanks

-- 
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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