When I search through logs it is extremely helpful to be able to us more than just contains this "text". To accomplish this I suggest adding options in front of text search like Contains, Does not Contain and maybe others like Begins With, Ends With, Exact, not exact, etc... The next enhancement would be to allow multiple text searches with these options. For example find all logs that contain "failure" and does not contain "323006". This way you can filter down logs even more to find what you want. See below for picture example:

The + and - would be to add and remove multiple search criteria see below for example:
View with multiple options
