The GIS standard and all the major DBs implementing GIS related
functions take coordinates as x,y that is longitude,latitude.
It was a bad start for Redis to do things differently, so even if this
means that existing users of the Geo module will be required to change
their code, Redis now conforms to the standard.
Usually Redis is very backward compatible, but this is not an exception
to this rule, since this is the first Geo implementation entering the
official Redis source code. It is not wise to try to be backward
compatible with code forks... :-)
Close#2637.
The GIS standard and all the major DBs implementing GIS related
functions take coordinates as x,y that is longitude,latitude.
It was a bad start for Redis to do things differently, so even if this
means that existing users of the Geo module will be required to change
their code, Redis now conforms to the standard.
Usually Redis is very backward compatible, but this is not an exception
to this rule, since this is the first Geo implementation entering the
official Redis source code. It is not wise to try to be backward
compatible with code forks... :-)
Close#2637.
The returned step was in some case not enough towards normal
coordinates (for example when our search position was was already near the
margin of the central area, and we had to match, using the east or west
neighbor, a very far point). Example:
geoadd points 67.575457940146066 -62.001317572780565 far
geoadd points 66.685439060295664 -58.925040587282297 center
georadius points 66.685439060295664 -58.925040587282297 200 km
In the above case the code failed to find a match (happens at smaller
latitudes too) even if far and center are at less than 200km.
Another fix introduced by this commit is a progressively larger area
towards the poles, since meridians are a lot less far away, so we need
to compensate for this.
The current implementation works comparably to the Tcl brute-force
stress tester implemented in the fuzzy test in the geo.tcl unit for
latitudes between -70 and 70, and is pretty accurate over +/-80 too,
with sporadic false negatives.
A more mathematically clean implementation is possible by computing the
meridian distance at the specified latitude and computing the step
according to it.
The returned step was in some case not enough towards normal
coordinates (for example when our search position was was already near the
margin of the central area, and we had to match, using the east or west
neighbor, a very far point). Example:
geoadd points 67.575457940146066 -62.001317572780565 far
geoadd points 66.685439060295664 -58.925040587282297 center
georadius points 66.685439060295664 -58.925040587282297 200 km
In the above case the code failed to find a match (happens at smaller
latitudes too) even if far and center are at less than 200km.
Another fix introduced by this commit is a progressively larger area
towards the poles, since meridians are a lot less far away, so we need
to compensate for this.
The current implementation works comparably to the Tcl brute-force
stress tester implemented in the fuzzy test in the geo.tcl unit for
latitudes between -70 and 70, and is pretty accurate over +/-80 too,
with sporadic false negatives.
A more mathematically clean implementation is possible by computing the
meridian distance at the specified latitude and computing the step
according to it.
1. We no longer use a fake client but just rewriting.
2. We group all the inserts into a single ZADD dispatch (big speed win).
3. As a side effect of the correct implementation, replication works.
4. The return value of the command is now correct.
1. We no longer use a fake client but just rewriting.
2. We group all the inserts into a single ZADD dispatch (big speed win).
3. As a side effect of the correct implementation, replication works.
4. The return value of the command is now correct.
This commit simplifies the implementation in a few ways:
1. zsetScore implementation improved a bit and moved into t_zset.c where
is now also used to implement the ZSCORE command.
2. Range extraction from the sorted set remains a separated
implementation from the one in t_zset.c, but was hyper-specialized in
order to avoid accumulating results into a list and remove the ones
outside the radius.
3. A new type is introduced: geoArray, which can accumulate geoPoint
structures in a vector with power of two expansion policy. This is
useful since we have to call qsort() against it before returning the
result to the user.
4. As a result of 1, 2, 3, the two files zset.c and zset.h are now
removed, including the function to merge two lists (now handled with
functions that can add elements to existing geoArray arrays) and
the machinery used in order to pass zset results.
5. geoPoint structure simplified because of the general code structure
simplification, so we no longer need to take references to objects.
6. Not counting the JSON removal the refactoring removes 200 lines of
code for the same functionalities, with a simpler to read
implementation.
7. GEORADIUS is now 2.5 times faster testing with 10k elements and a
radius resulting in 124 elements returned. However this is mostly a
side effect of the refactoring and simplification. More speed gains
can be achieved by trying to optimize the code.
This commit simplifies the implementation in a few ways:
1. zsetScore implementation improved a bit and moved into t_zset.c where
is now also used to implement the ZSCORE command.
2. Range extraction from the sorted set remains a separated
implementation from the one in t_zset.c, but was hyper-specialized in
order to avoid accumulating results into a list and remove the ones
outside the radius.
3. A new type is introduced: geoArray, which can accumulate geoPoint
structures in a vector with power of two expansion policy. This is
useful since we have to call qsort() against it before returning the
result to the user.
4. As a result of 1, 2, 3, the two files zset.c and zset.h are now
removed, including the function to merge two lists (now handled with
functions that can add elements to existing geoArray arrays) and
the machinery used in order to pass zset results.
5. geoPoint structure simplified because of the general code structure
simplification, so we no longer need to take references to objects.
6. Not counting the JSON removal the refactoring removes 200 lines of
code for the same functionalities, with a simpler to read
implementation.
7. GEORADIUS is now 2.5 times faster testing with 10k elements and a
radius resulting in 124 elements returned. However this is mostly a
side effect of the refactoring and simplification. More speed gains
can be achieved by trying to optimize the code.
For some reason the Geo PR included disabling the fact that Redis is
compiled with optimizations. Apparently it was just @mattsta attempt to
speedup the modify-compile-test iteration and there are no other
reasons.
For some reason the Geo PR included disabling the fact that Redis is
compiled with optimizations. Apparently it was just @mattsta attempt to
speedup the modify-compile-test iteration and there are no other
reasons.
This feature apparently is not going to be very useful, to send a
GEOADD+PUBLISH combo is exactly the same. One that would make a ton of
difference is the ability to subscribe to a position and a radius, and
get the updates in terms of objects entering/exiting the area.
This feature apparently is not going to be very useful, to send a
GEOADD+PUBLISH combo is exactly the same. One that would make a ton of
difference is the ability to subscribe to a position and a radius, and
get the updates in terms of objects entering/exiting the area.
