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This patch largely reverts what I did in commitsc9b0c678dand78e73e875. The maximum cover length limit that I added in78e73e875(to band-aid over c9b0c678d's performance issues) creates too many user-visible behavior discrepancies, as complained of for example in bug #17691. The real problem with hlCover() is not what I thought at the time, but more that it seems to have been designed with only AND tsquery semantics in mind. It doesn't work quite right for OR, and even less so for NOT or phrase queries. However, we can improve that situation by building a variant of TS_execute() that returns a list of match locations. We already get an ExecPhraseData struct representing match locations for the primitive case of a simple match, as well as one for a phrase match; we just need to add some logic to combine these for AND and OR operators. The result is a list of ExecPhraseDatas, which hlCover can regard as having simple AND semantics, so that its old algorithm works correctly. There's still a lot not to like about ts_headline's behavior, but I think the remaining issues have to do with the heuristics used in mark_hl_words and mark_hl_fragments (which, likewise, were not revisited when phrase search was added). Improving those is a task for another day. Patch by me; thanks to Alvaro Herrera for review. Discussion: https://postgr.es/m/840.1669405935@sss.pgh.pa.us
# Generating dummy probes If Postgres isn't configured with dtrace enabled, we need to generate dummy probes for the entries in probes.d, that do nothing. This is accomplished in Unix via the sed script `Gen_dummy_probes.sed`. We used to use this in MSVC builds using the perl utility `psed`, which mimicked sed. However, that utility disappeared from Windows perl distributions and so we converted the sed script to a perl script to be used in MSVC builds. We still keep the sed script as the authoritative source for generating these dummy probes because except on Windows perl is not a hard requirement when building from a tarball. So, if you need to change the way dummy probes are generated, first change the sed script, and when it's working generate the perl script. This can be accomplished by using the perl utility s2p. s2p is no longer part of the perl core, so it might not be on your system, but it is available on CPAN and also in many package systems. e.g. on Fedora it can be installed using `cpan App::s2p` or `dnf install perl-App-s2p`. The Makefile contains a recipe for regenerating Gen_dummy_probes.pl, so all you need to do is once you have s2p installed is `make Gen_dummy_probes.pl` Note that in a VPATH build this will generate the file in the vpath tree, not the source tree.