wp_load_core_site_options() query optimization

[ellisgl]

wp_load_core_site_options() query doesn't use an index. This will trigger an entry in MySQL slow query log. It's more an

Suggested fix: Use "FORCE INDEX(meta_key)" to ensure an index is used.

[ellisgl]

Patch

[scribu]

Your description seems to be truncated.

Also, you say FORCE INDEX(meta_key) in the description, but write FORCE INDEX(site_id).

Please clarify.

[ellisgl]

ER
It's more of a minor annoyance for a small setup.

Suggested fix: Use "FORCE INDEX(site_id)" to ensure an index is used.

[ellisgl]

Replying to ellisgl:

ER
It's more of a minor annoyance for a small setup.

Suggested fix: Use "FORCE INDEX(site_id)" to ensure an index is used.

Of course if you have a lot of sites, then this could become an issue.

[mrmist]

Has this been tested against a larger site? If the mysql optimizer is not using an index for a small table, it could be because it's determined that it's more efficient not to..

[ellisgl]

Replying to mrmist:

Has this been tested against a larger site? If the mysql optimizer is not using an index for a small table, it could be because it's determined that it's more efficient not to..

In our dev system, we currently have 7 sites defined.

[mrmist]

OK. I guess it depends on what else goes into the multi-site meta table as to how big that particular table might get. What I'm trying to say is that for, say, 10 rows it's probably more expensive to do the lookup, and that's why the index is ignored in the first place. Some execution data from large and small sites with or without the patch might be worthwhile to decide whether the index should be forced or not..

Sadly I don't have a multi-site install to test on, big or small.

[ellisgl]

My finding were that 40 rows were scanned before, after 39. I need to setup a large system. This would have to be next week.

[ellisgl]

Here's a question, how do get more than 1 site id in the 'sitemeta' table the normal way. I add sites, and it doesn't add anything.. =/ I could cheat and run a script that create a ton of copies.

[ellisgl]

Took my own advise and cheated. If there is more than 1 site_id, then the optimizer does kick in. Setting ticket to "invalid". Sorry for wasting your time.