5 Commits (f339a998ffe6fb8aa8c114a33316e97b56cb1513)

Author	SHA1	Message	Date
Tom Lane	de1d042f59	Support index-only scans in contrib/cube and contrib/seg GiST indexes. ... To do this, we only have to remove the compress and decompress support functions, which have never done anything more than detoasting. In the wake of commit d3a4f89d8, this results in automatically enabling index-only scans, since the core code will now know that the stored representation is the same as the original data (up to detoasting). The only exciting part of this is that ALTER OPERATOR FAMILY lacks a way to drop a support function that was declared as being part of an opclass rather than being loose in the family. For the moment, we'll hack our way to a solution with a manual update of the pg_depend entry type, which is what distinguishes the two cases. Perhaps someday it'll be worth providing a cleaner way to do that, but for now it seems like a very niche problem. Note that the underlying C functions remain, to support use of the shared libraries with older versions of the modules' SQL declarations. Someday we may be able to remove them, but not soon. Andrey Borodin, reviewed by me Discussion: https://postgr.es/m/D0F53A05-4F4A-4DEC-8339-3C069FA0EE11@yandex-team.ru	8 years ago
Tom Lane	7d08ce286c	Distinguish selectivity of < from <= and > from >=. ... Historically, the selectivity functions have simply not distinguished < from <=, or > from >=, arguing that the fraction of the population that satisfies the "=" aspect can be considered to be vanishingly small, if the comparison value isn't any of the most-common-values for the variable. (If it is, the code path that executes the operator against each MCV will take care of things properly.) But that isn't really true unless we're dealing with a continuum of variable values, and in practice we seldom are. If "x = const" would estimate a nonzero number of rows for a given const value, then it follows that we ought to estimate different numbers of rows for "x < const" and "x <= const", even if the const is not one of the MCVs. Handling this more honestly makes a significant difference in edge cases, such as the estimate for a tight range (x BETWEEN y AND z where y and z are close together). Hence, split scalarltsel into scalarltsel/scalarlesel, and similarly split scalargtsel into scalargtsel/scalargesel. Adjust <= and >= operator definitions to reference the new selectivity functions. Improve the core ineq_histogram_selectivity() function to make a correction for equality. (Along the way, I learned quite a bit about exactly why that function gives good answers, which I tried to memorialize in improved comments.) The corresponding join selectivity functions were, and remain, just stubs. But I chose to split them similarly, to avoid confusion and to prevent the need for doing this exercise again if someone ever makes them less stubby. In passing, change ineq_histogram_selectivity's clamp for extreme probability estimates so that it varies depending on the histogram size, instead of being hardwired at 0.0001. With the default histogram size of 100 entries, you still get the old clamp value, but bigger histograms should allow us to put more faith in edge values. Tom Lane, reviewed by Aleksander Alekseev and Kuntal Ghosh Discussion: https://postgr.es/m/12232.1499140410@sss.pgh.pa.us	8 years ago
Tom Lane	749a787c5b	Handle contrib's GIN/GIST support function signature changes honestly. ... In commits 9ff60273e3 and dbe2328959 I (tgl) fixed the signatures of a bunch of contrib's GIN and GIST support functions so that they would pass validation by the recently-added amvalidate functions. The backend does not actually consult or check those signatures otherwise, so I figured this was basically cosmetic and did not require an extension version bump. However, Alexander Korotkov pointed out that that would leave us in a pretty messy situation if we ever wanted to redefine those functions later, because there wouldn't be a unique way to name them. Since we're going to be bumping these extensions' versions anyway for parallel-query cleanups, let's take care of this now. Andreas Karlsson, adjusted for more search-path-safety by me	10 years ago
Teodor Sigaev	33bd250f6c	Cube extension kNN support ... Introduce distance operators over cubes: <#> taxicab distance <-> euclidean distance <=> chebyshev distance Also add kNN support of those distances in GiST opclass. Author: Stas Kelvich	10 years ago
Tom Lane	629b3af27d	Convert contrib modules to use the extension facility. ... This isn't fully tested as yet, in particular I'm not sure that the "foo--unpackaged--1.0.sql" scripts are OK. But it's time to get some buildfarm cycles on it. sepgsql is not converted to an extension, mainly because it seems to require a very nonstandard installation process. Dimitri Fontaine and Tom Lane	15 years ago