Contents
- 1 Why is PostgreSQL database update query so slow?
- 2 How to do simple update in PostgreSQL database?
- 3 How to speed up PostgreSQL count ( distinct ) query?
- 4 Is there any way to improve performance in PostgreSQL?
- 5 When to update rows in PostgreSQL database?
- 6 Is it slow to update 3 million records in one statement?
Why is PostgreSQL database update query so slow?
If you are looping each row and performing an update statement, you are running potentially millions of individual updates which is why it will perform incredibly slowly.
How to do simple update in PostgreSQL database?
I am trying a simple UPDATE table SET column1 = 0 on a table with ~3 million rows on Postegres 8.4 but it is taking forever to finish. It has been running for more than 10 min. now in my last attempt.
How long does PostgreSQL hot update query take?
My first try was to group them in transaction of 300K updates directly on a specific partition as Postgresql not always optimize prepared queries if you use partitions. Gives 1,500 updates/sec. which means each run would take at least 18 hours. HOT updates solution as described here with FILLFACTOR=50.
How to speed up PostgreSQL count ( distinct ) query?
The same plan as for the CTE could probably also be produced by other methods (window functions) If your count (distinct (x)) is significantly slower than count (x) then you can speed up this query by maintaining x value counts in different table, for example table_name_x_counts (x integer not null, x_count int not null), using triggers.
Is there any way to improve performance in PostgreSQL?
This query is running pretty slowly; it takes about 7.5s, compared to which takes about 435ms. Is there any way to change my query to improve performance? I’ve tried grouping and doing a regular count, as well as putting an index on x; both have the same 7.5s execution time. This is much faster than:
Which is faster CTE or PostgreSQL count?
This is much faster than: The same plan as for the CTE could probably also be produced by other methods (window functions)
When to update rows in PostgreSQL database?
Though not if the values are all non zero already, but updating fewer rows “can help” since otherwise it updates them and all indexes regardless of whether the value changed or not.
Is it slow to update 3 million records in one statement?
If you are running a single update statement for all records in one statement it would run a lot faster, and if this process is slow then it’s probably down to your hardware more than anything else. 3 million is a lot of records.
How to update columns in PostgreSQL SQL query?
No matter whether the column being updated is indexed or not, it seems like psql updates all the indices for all the updated rows. After the update is finished, add the constraints/indices back. Try this (note that generalFreq starts as type REAL, and stays the same):