Hello hackers, The type smgr has only one value 'magnetic disk'. ~15 years ago it also had a value 'main memory', and in Berkeley POSTGRES 4.2 there was a third value 'sony jukebox'. Back then, all tables had an associated block storage manager, and it was recorded as an attribute relsmgr of pg_class (or pg_relation as it was known further back). This was the type of that attribute, removed by Bruce in 3fa2bb31 (1997).
Nothing seems to break if you remove it (except for some tests using it in an incidental way). See attached. Motivation: A couple of projects propose to add new smgr implementations alongside md.c in order to use bufmgr.c for more kinds of files, but it seems entirely bogus to extend the unused smgr type to cover those. -- Thomas Munro https://enterprisedb.com
0001-Remove-the-vestigial-smgr-type.patch
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