X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/4e6d729529c94486a50cf135dfbbdcf841790200..479c1575e119d93a0d239fb192ad4ed3d03cad88:/db/functions/functions.sql diff --git a/db/functions/functions.sql b/db/functions/functions.sql deleted file mode 100644 index 5e3d4bcb3..000000000 --- a/db/functions/functions.sql +++ /dev/null @@ -1,73 +0,0 @@ --------------------------------------------------------------------------------- --- SQL versions of the C database functions. --- --- Pure pl/pgsql versions are *slower* than the C versions, and not recommended --- for production use. However, they are significantly easier to install, and --- require fewer dependencies. --------------------------------------------------------------------------------- - --- tile_for_point function returns a Morton-encoded integer representing a z16 --- tile which contains the given (scaled_lon, scaled_lat) coordinate. Note that --- these are passed into the function as (lat, lon) and should be scaled by --- 10^7. --- --- The Morton encoding packs two dimensions down to one with fairly good --- spatial locality, and can be used to index points without the need for a --- proper 2D index. -CREATE OR REPLACE FUNCTION tile_for_point(scaled_lat int4, scaled_lon int4) - RETURNS int8 - AS $$ -DECLARE - x int8; -- quantized x from lon, - y int8; -- quantized y from lat, -BEGIN - x := round(((scaled_lon / 10000000.0) + 180.0) * 65535.0 / 360.0); - y := round(((scaled_lat / 10000000.0) + 90.0) * 65535.0 / 180.0); - - -- these bit-masks are special numbers used in the bit interleaving algorithm. - -- see https://graphics.stanford.edu/~seander/bithacks.html#InterleaveBMN - -- for the original algorithm and more details. - x := (x | (x << 8)) & 16711935; -- 0x00FF00FF - x := (x | (x << 4)) & 252645135; -- 0x0F0F0F0F - x := (x | (x << 2)) & 858993459; -- 0x33333333 - x := (x | (x << 1)) & 1431655765; -- 0x55555555 - - y := (y | (y << 8)) & 16711935; -- 0x00FF00FF - y := (y | (y << 4)) & 252645135; -- 0x0F0F0F0F - y := (y | (y << 2)) & 858993459; -- 0x33333333 - y := (y | (y << 1)) & 1431655765; -- 0x55555555 - - RETURN (x << 1) | y; -END; -$$ LANGUAGE plpgsql IMMUTABLE; - - --- xid_to_int4 converts a PostgreSQL transaction ID (xid) to a 32-bit integer --- which can then be used to efficiently find rows which have changed between --- two given transactions. This is currently used by Osmosis to extract a --- stream of edits for "diff replication" **HOWEVER** this is a pain point, as --- (ab)using the xid in this way is _not_ supported or recommended by Postgres --- devs. It is preventing us upgrading to PostgreSQL version 10+, and will --- hopefully be replaced Real Soon Now. --- --- From the Osmosis distribution by Brett Henderson: --- https://github.com/openstreetmap/osmosis/blob/master/package/script/contrib/apidb_0.6_osmosis_xid_indexing.sql -CREATE OR REPLACE FUNCTION xid_to_int4(t xid) - RETURNS integer - AS -$$ -DECLARE - tl bigint; - ti int; -BEGIN - tl := t; - - IF tl >= 2147483648 THEN - tl := tl - 4294967296; - END IF; - - ti := tl; - - RETURN ti; -END; -$$ LANGUAGE 'plpgsql' IMMUTABLE STRICT;