Re: [sqlalchemy] Large increase in memory use when upgrading from 1.3 to 1.4

[Mike Bayer]

On Fri, Oct 21, 2022, at 12:00 AM, 'Tony Cosentini' via sqlalchemy wrote:
> Hi,
> 
> We recently upgraded our application (a Flask web app) from SQLAlchemy 1.3.19 
> to 1.4.41.
> 
> Overall things are stable, but we have noticed a very large increase in 
> memory use:
> Screen Shot 2022-10-21 at 11.26.18 AM.png
> 
> Is this from the new query caching feature? I'm planning on getting some heap 
> dumps to see if there is something obvious, but thought I'd ask here as well.

you would be able to tell if you set query_cache_size=0 which then resolves the 
memory issue.

The cache itself uses memory, which can cause memory increases.  However we 
have a slight concern for the case of extremely large and highly nested SQL 
constructs that might be generating unreasonably large cache keys.  We had one 
user with this problem some months ago and they were not able to give us 
details in order to reproduce the problem. query_cache_size=0 would prevent 
this problem also, but if you have very nested queries, particularly with CTEs, 
we'd be curious if you can isolate particular queries that might have that 
issue.


> 
> The application is using the Postgres dialect. Nothing else was changed 
> besides the SQLAlchemy version. It's running in a Docker container with 8 GB 
> of RAM allocated to it.
> 
> Anyway, I'll continue digging in more, but just asking in case there is 
> something obvious,
> Tony 
> 
> 
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
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> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
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> .
>  
> 

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[sqlalchemy] Large increase in memory use when upgrading from 1.3 to 1.4

['Tony Cosentini' via sqlalchemy]

Hi,

We recently upgraded our application (a Flask web app) from SQLAlchemy 
1.3.19 to 1.4.41.

Overall things are stable, but we have noticed a very large increase in 
memory use:
[image: Screen Shot 2022-10-21 at 11.26.18 AM.png]

Is this from the new query caching feature? I'm planning on getting some 
heap dumps to see if there is something obvious, but thought I'd ask here 
as well.

The application is using the Postgres dialect. Nothing else was changed 
besides the SQLAlchemy version. It's running in a Docker container with 8 
GB of RAM allocated to it.

Anyway, I'll continue digging in more, but just asking in case there is 
something obvious,
Tony

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
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[sqlalchemy] iterate sqlalchemy query over for loop in my template python-flask

[Abdellah ALAOUI ISMAILI]

Hello,
I call a function in my template that returns sqlalchemy query result, 
(color value from the name of the tag). this is the query function :

*def get_tag_color(name): *
*return db.session.query(Tag.tag_color).filter(Tag.tag_name == 
name).scalar() *

and I call it in my template file:
* {% if server.tags %}*
* {% for tag in server.tags.split(",") %} *
*  {{tag}} *
* {% endfor %} {% endif %} * 

the problem is that I get just one result of the first tag. do you have any 
idea what I miss?

Thank you 

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The Python SQL Toolkit and Object Relational Mapper

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