if its faster its good, if you like to create a PR you are welcome please do this against j4 branch.

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/23983

@artur-stepien as there is no Answer i close this one, it can always reopened.

I can prepare this in a fast way by adding a string query to Table class. But I think this should be added to the Query object in a first place. Cause this is something that can be used in models of bigger components. I'll check it and let you know soon.

@artur-stepien do you have benchmarks or any information about b/c
@alikon can you check this suggestion?

@HLeithner There are benchmarks. Here is one http://sqlblog.com/blogs/andrew_kelly/archive/2007/12/15/exists-vs-count-the-battle-never-ends.aspx
In short. The more records in the table the more expensive COUNT(*) is. Cause COUNT requires from the server to look for every row matching query. Where EXISTS stops after the first one found.

And after I create the PR I will make a benchmark too to check if update will not do worse in Joomla! cause of framework overhead.

ok please go forward and create a PR against 4.0-dev thx

maybe we should simply look at schema

select constraint_name
from information_schema.table_constraints
where table_name = 'mytable'
and table_schema = 'myschema'
and constraint_name = 'PRIMARY'

schema is sometimes really slow, especially on older mysql versions.

maybe this one is better

SHOW KEYS FROM table WHERE Key_name = 'PRIMARY'

works on all supported versions? At least it looks really simple.

Why do you wan't to look for a schema if it the problem is completely different? Its about the fact, that Table uses COUNT(*) do determinate if the row exists. The name of the function is just misleading. We already know what is the primary key cause it is provided as a parameter of class extending Table. When autoincrement is disabled on the Table class it looks if there is a row with provided primary keys. And instead of using EXISTS() that just returns the fact if there is a row matching query, the COUNT(*) counts the rows (it access the data etc). Its is a small window where the change makes a performance improvement but it is there. That hasPrimaryKey is used when table uses a composite primary key. Now, I didn't saw a single core component using such keys. But it is often used on a big components and custom made components consisting of multiple tables. I will prepare the change and a testing method. Just give me time.

@HLeithner And as for the support. From what I already found it EXISTS() is implemented in MySQL/MariaDB, MS SQL, PostgreSQL and even SQLite. As for the version. Change shouldn't affect negatively any of the components cause function behavior is same. Just the method changing for a faster one.

ok so can you please provide a PR?

@HLeithner I need a week or so. Plenty of projects to finish.

no problem we have some time left till J4 beta ;-)

The name of the function is just misleading.

@artur-stepien absolutely yes, sorry for the misunderstand, looking forward to your PR

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