1. Currently, cube extension has CUBE_MAX_DIM set as 100.
A recent github issue. [1]
2. To compile a custom version of the extension off the tree requires:
```
make -C contrib/custom_cube USE_PGXS=1
```
3. But utils/float.h required by cube.c and cubeparse.y is not installed.
It's not present in the latest release file [2],
nor being installed when running
make install when compiling from git.
4. Current workaround is to use
```
#include "../../src/include/utils/float.h"
```
in cube.c and cubeparse.y when compiling in git tree.
[1] https://github.com/postgres/postgres/pull/38
[2] https://github.com/postgres/postgres/archive/REL_11_2.tar.gz