avarab wrote:

We're not going to allow searching for a substring anywhere in a string in the
log_user, log_title or log_comment fields in miser mode. Currently there is an
index (In reply to comment #0)

If you seach in the Logs (Block, Protection, Deletion, ...) you can enter search
informaiton in the "User" and/or "Title" form field. You will only be able to
find matches if you enter the complete name. It seems not to be possible to only
enter a part of the name

Confirmed

If an article "This is just an example to explain the bug" is deleted, it should
be able to find it in the block log by entering "just an example" and hitting
return. Or "*just an example*".

LIKE "%foo%" would be too expensive an operating to enable since it would result
in a table scan.

gangleri wrote:

As I remember a "substring search" was available some time ago at
http://en.wikipedia.org/wiki/Special:Imagelist .
Now you may search for "arba" at
http://en.wikipedia.org/w/index.php?title=Special:Newimages&limit=48

Maybe a lighter solution like [[Special:Userlist]] would be possible? Since a
few month a search with e.g. "Ray" gives a usernames list like "Ray*". Maybe a
searchmattern "Ray*" is not so expensive then "%ray%"?

Realized for field "title" with r20409.

Added an option for search e.g. "Test%". Other forms like "T%est%" are too
expensive and disabled. I will close this bug as FIXED. If someone needs a
pattern search for the field "user" too feel free to reopen this bug or file a
new bug.