![]() ![]() db files, and a larger number of indexes, maps, shadows, and more.Īt its most basic level in macOS, each search is submitted as an MDQuery to the Spotlight server mds, which performs its search asynchronously and posts notifications of its progress as it gathers the results. Cross-indexing saves Spotlight from having to search through every file checking its type to discover which contain the desired UTI for any given search. Values for the type are UTIs such as public.text. For example, each file indexed has a type, which can be accessed using the (search) key kMDItemContentTypeTree. There is no simple solution to this, as Spotlight’s index conforms to the general principle of ‘rubbish in, rubbish out’.Īpple hasn’t released details of the structure of data within Spotlight’s indexes, but it’s keyed, with cross-indexing for economy of effort in searching. Although these may appear perfectly readable, the text extracted from them often contains errors, such as cftem for often, which makes searching them a nightmare. PDF documents merit special consideration, in particular those which contain scanned pages of printed documents together with OCRed text overlaid on them. Apps which don’t provide any plugin to handle their proprietary files make it impossible to use Spotlight to search for their content, and buggy plugins can not only deliver corrupt data for indexing, but can cause mdworker processes to crash repeatedly, which may have impact on your Mac’s performance. The quality of the data indexed is dependent on that in the file, and its mdimporter plugin. content, normally text, exported from the main data of the file, again using the mdimporter plugin. ![]() structured metadata from the main data in the file, as specified by that file type’s mdimporter plugin examples include EXIF data.extended attributes, stored in the file system metadata these include keywords and copyright information, where provided.What I didn’t examine was exactly what goes into those indexes, nor how to search them.Ĭontent extracted from each file that’s indexed by an mdworker process includes: In the previous article, I explained how Spotlight builds and maintains its indexes of the files on volumes.
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