Form submit takes too long

[Maurice Waka]

I noticed that my form submit takes too long, almost 45 seconds sometimes. The more data I add to the database and I need to fetch it, the more longer it takes to submit.

This is my code

           

<div class="bottom_wrapper clearfix">
                <div class="message_input_wrapper">
                    {{=form.custom.begin}}
                    <textarea id="message_input" type="text"name="message"  placeholder="Type your message here..."></textarea>
                    <button>send</button>
                    {{=form.custom.end}}
                </div>
                <div class="message_template">
                    <li class="message">
                        <div class="message-data-time" ></div>
                        <div class="text_wrapper">
                            <div class="text"></div>
                        </div>
                    </li>
                </div>
            </div>

Controller function

def c_function():
    form = SQLFORM(db.post).process()
    row = db(db.post.author== auth.user.id).select(db.post.id, db.post.message, orderby=~db.post.id, limitby=(0,1)).first()
    names = row.message if row else None
    db.answers.insert(quest=names, message=report())
    replies = db(db.answers.author == auth.user.id).select(db.answers.ALL)[-10:-1]
    return dict(form=form,names=names,replies=replies)

[Anthony]

    db.answers.insert(quest=names, message=report())

What does report() do? Is that an expensive function?

 

    replies = db(db.answers.author == auth.user.id).select(db.answers.ALL)[-10:-1]

Above you are selecting every record in the db.answers table and converting them to Python objects -- is that a big table? You should instead use limitby to select only the records you want.

Anthony

[Maurice Waka]

Answers is a small table, can have up to 100 rows. I'll introduce the limitby(). There are several functions that an item loops through, almost 100, but with a filter to limit the number of functions, with the final result returned by report() 

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[Leonel Câmara]

Apart from the obvious problem Anthony pointed. Are you using sqlite in a highly concurrent environment? 

[justice Nanhou]

Hallo Maurice,

it is know issue for all application and all framworks.

which database are you using ? 

- my first attempt will be to try to add indexes in the post and answers Table on the field author.

- secondly i will try to change this row

row = db(db.post.author== auth.user.id).select(db.post.id, db.post.message, orderby=~db.post.id, limitby=(0,1)).first()

to this

row = db(db.post.author== auth.user.id).select(db.post.id, db.post.message, orderby=~db.post.id).first()

limitby ist not needed in that case. it is just my opinion.

[Lovedie JC]

Yes. Been away. But I am looking into this. I'll let you know the results.

Regards 

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- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
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[Lovedie JC]

Am using sqlite.storage

On Sun, 2 Sep 2018, 21:03 justice Nanhou <justice...@gmail.com> wrote:

[Maurice Waka]

Hey @Lovdie. Can we have a look at this later? 

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[Anthony]

- my first attempt will be to try to add indexes in the post and answers Table on the field author.

- secondly i will try to change this row

row = db(db.post.author== auth.user.id).select(db.post.id, db.post.message, orderby=~db.post.id, limitby=(0,1)).first()

to this

row = db(db.post.author== auth.user.id).select(db.post.id, db.post.message, orderby=~db.post.id).first()

limitby ist not needed in that case. it is just my opinion.

Why would you not use limitby? Without limitby, the database will return every record in the table, and the the DAL will have to parse every record and convert it to a Row object -- and then all of those Row objects will simply be ignored, as only the first will be used in the code.

Anthony

[Massimo Di Pierro]

I understand the confusion. In SQLAlchemy for example people use .first() for fetch one record. In web2py the feching is by the select. .first() just gives you the fist of the records that were retrieved.

[Maurice Waka]

Noted. I removed some while loops with tremendous results. It now works well.

Regards.

--

Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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