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help / color / mirror / Atom feedFrom: Daniel Westermann (DWE) <[email protected]>
To: Bruce Momjian <[email protected]>
To: [email protected] <[email protected]>
Subject: Re: Instead of using the bloom index, a parallel sequencial scan is used with this example
Date: Tue, 5 Nov 2019 20:28:57 +0000
Message-ID: <VI1PR09MB4142FC41A11AE3FFAA52B1F9D27E0@VI1PR09MB4142.eurprd09.prod.outlook.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
>>On Thu, Oct 24, 2019 at 03:17:06PM +0000, PG Doc comments form wrote:
>> The following documentation comment has been logged on the website:
>>
>>Page: https://www.postgresql.org/docs/12/bloom.html
>> Description:
>I cleaned up your script and created an SQL file that can be piped into
>psql, attached. I see the bloomidx index being used without and with
>the ANALYZE, output attached. I tested this on git master, and back
>through PG 10. Would you please run these queries and post the output:
Thanks for having a look, Bruce. You test case is not exactly the same as in the documentation. For you "temporary table" test case I indeed see the bloom index getting used. Doing the same with a normal table results in a parallel seq scan.
postgres=# SELECT version();
version
----------------------------------------------------------------------------------------------------------------------------
PostgreSQL 12.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39), 64-bit
(1 row)
postgres=# SELECT name, current_setting(name), source
postgres-# FROM pg_settings
postgres-# WHERE source NOT IN ('default', 'override');
name | current_setting |
----------------------------+--------------------+----------------------
application_name | psql | client
client_encoding | UTF8 | client
DateStyle | ISO, MDY | configuration file
default_text_search_config | pg_catalog.english | configuration file
dynamic_shared_memory_type | posix | configuration file
lc_messages | en_US.utf8 | configuration file
lc_monetary | de_CH.UTF-8 | configuration file
lc_numeric | de_CH.UTF-8 | configuration file
lc_time | en_US.UTF-8 | configuration file
listen_addresses | * | configuration file
log_timezone | Europe/Zurich | configuration file
max_connections | 100 | configuration file
max_stack_depth | 2MB | environment variable
max_wal_size | 1GB | configuration file
min_wal_size | 80MB | configuration file
port | 5432 | environment variable
shared_buffers | 128MB | configuration file
TimeZone | Europe/Zurich | configuration file
Regards
Daniel
Attachments:
[application/sql] bloom2.sql (625B, 3-bloom2.sql)
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Subject: Re: Instead of using the bloom index, a parallel sequencial scan is used with this example
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