On Fri, Jan 8, 2016 at 12:05 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Whoever thought this was a good idea: > > StaticAssertStmt(NAMEDATALEN <= MAX_LEVENSHTEIN_STRLEN, > "Levenshtein hinting mechanism restricts NAMEDATALEN"); > > is nuts.
Then I must be nuts. > A minimal fix that would not put stumbling blocks in the way of changes > to NAMEDATALEN is to redefine MAX_LEVENSHTEIN_STRLEN as > Max(255, NAMEDATALEN). But I wonder why we have to have an arbitrary limit > in this code at all. I trust nobody here believes this is the only O(N^2) > algorithm in the backend; the others don't have this sort of thing in > front of them. The default NAMEDATALEN is of course 64. I didn't feel that the static assertion was especially restrictive, given that it still leaves significant headroom. I'm slightly surprised that this cropped up. I didn't want to presume that the algorithm being O(N^2) was the only reason for the restriction. This comment seems pretty scary to me: /* * For security concerns, restrict excessive CPU+RAM usage. (This * implementation uses O(m) memory and has O(mn) complexity.) */ if (m > MAX_LEVENSHTEIN_STRLEN || n > MAX_LEVENSHTEIN_STRLEN) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("argument exceeds the maximum length of %d bytes", MAX_LEVENSHTEIN_STRLEN))); -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers