Hi, Nikita! I take a look to this patchset. My first notes are following.
* 0003-Extract-index_store_orderby_distances-v02.patch Function index_store_orderby_distances doesn't look general enough for its name. GiST supports ordering only by float4 and float8 distances. SP-GiST also goes that way. But in the future, access methods could support distances of other types. Thus, I suggest to rename function to index_store_float8_orderby_distances(). * 0004-Add-kNN-support-to-SP-GiST-v02.patch Patch didn't applied cleanly. patching file doc/src/sgml/spgist.sgml patching file src/backend/access/spgist/Makefile patching file src/backend/access/spgist/README patching file src/backend/access/spgist/spgscan.c Hunk #5 succeeded at 242 with fuzz 2. Hunk #11 FAILED at 861. 1 out of 11 hunks FAILED -- saving rejects to file src/backend/access/spgist/spgscan.c.rej patching file src/backend/access/spgist/spgtextproc.c patching file src/backend/access/spgist/spgutils.c Hunk #3 succeeded at 65 (offset 1 line). Hunk #4 succeeded at 916 (offset 1 line). patching file src/backend/access/spgist/spgvalidate.c patching file src/include/access/spgist.h patching file src/include/access/spgist_private.h Hunk #4 FAILED at 191. Hunk #5 succeeded at 441 (offset -230 lines). 1 out of 5 hunks FAILED -- saving rejects to file src/include/access/spgist_private.h.rej I had to apply failed chunks manually. While trying to compile that I faced compile error. spgtextproc.c:89:7: error: no member named 'suppLen' in 'struct spgConfigOut' cfg->suppLen = 0; /* we don't need any supplimentary data */ ~~~ ^ I noticed that this line was removed in the next patch. After removing it, I faced following error. make: *** No rule to make target `spgproc.o', needed by `objfiles.txt'. Stop. After removing spgproc.o from src/backend/access/spgist/Makefile, I finally succeed to compile it. *************** AUTHORS > *** 371,373 **** > --- 376,379 ---- > > Teodor Sigaev <teo...@sigaev.ru> > Oleg Bartunov <o...@sai.msu.su> > + Vlad Sterzhanov <glide...@gmail.com> I don't think it worth mentioning here GSoC student who made just dirty prototype and abandon this work just after final evaluation. More generally, you switched SP-GiST from scan stack to pairing heap. We should check if it introduces overhead to non-KNN scans. Also some benchmarks comparing KNN SP-GIST vs KNN GiST would be now. * 0005-Add-ordering-operators-to-SP-GiST-kd_point_ops-and-quad_point_ops-v02.patch I faced following warning. spgproc.c:32:10: warning: implicit declaration of function 'get_float8_nan' is invalid in C99 [-Wimplicit-function-declaration] return get_float8_nan(); ^ 1 warning generated. * 0006-Add-spg_compress-method-to-SP-GiST-v02.patch * 0007-Add-SP-GiST-opclasses-poly_ops-and-circle_ops-v02.patch I think this is out of scope for KNN SP-GiST. This is very valuable, but completely separate feature. And it should be posted and discussed separately. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company