15 questions
-1
votes
1
answer
293
views
how to hint inner select query to run parallel for bulk update
A SELECT query runs a "Parallel Seq" scan with a good number of workers. Now when this query is used as a subquery in an UPDATE it regresses to a "Seq" scan, i.e. non parallel.
A ...
- 125
0
votes
1
answer
696
views
Postgresql 15 query optimizer refuses to parallelize a query on a partitioned table
I have a table "weather" that stores weather parameters for 45 years of entire Europe area with 400 million of record partitioned by range in an Oracle database managed through 19c instance ...
0
votes
1
answer
2k
views
Is it possible to execute parallel query in Postgres which queries partitioned table by using union all?
Hello I'm playing around with postgres as a search engine by using GIN indexes with trigram module and partitioned table and I'm trying to parallelize the query but no matter what I set the query is ...
- 33
4
votes
2
answers
6k
views
Understanding how many parallel workers remain from a worker pool across sessions for PostgreSQL parallel queries?
Let's say I have a pool of 4 parallel workers in my PostgreSQL database configuration. I also have 2 sessions.
In session#1, the SQL is currently executing, with my planner randomly choosing to ...
- 61
0
votes
1
answer
231
views
PostgreSQL parallel queries using SPI possible?
I am using PostgreSQL's Server Programming Interface (SPI) to build my postgres extension and execute my query. Please see this detailed example, or the following simple code sample:
int ret = ...
- 1,689
1
vote
2
answers
256
views
Postgres, is query performance depending on front-end tool?
I was trying the same query
select column_1, count(1)
from table
group by 1
order by 1 desc
with several front-end tools, and I was getting very different results.(I ran query several time to avoid ...
- 515
5
votes
1
answer
483
views
Postgres 9.6 parallel XPath
I've set up Postgres 9.6 and checked on a large table of random integers that parallel queries are working.
However, a simple XPath query on an XML column of another table is always sequential. Both ...
- 11.2k
6
votes
1
answer
2k
views
Parallel queries on CTE for writing operations in PostgreSQL
From PostgreSQL 9.6 Release Notes:
Only strictly read-only queries where the driving table is accessed via a sequential scan can be parallelized.
My question is: If a CTE (WITH clause) contains only ...
- 3,749