NEW SORT operator

[aburamadan]

added SORT operator to sort an MDD by a ranking function. Refer to included docs for more info.
added mandatory test_select test cases.
named axes are supported.
also added QtAxisSDom which returns the SDOM of an array at an axis.(required for SORT op.)

[Bang Pham Huu]

@aburamadan: I built the new rasdaman in master branch with your patch and I couldn't run some queries from your examples at ​file:///home/rasdaman/rasdaman_community/rasdaman/doc/main/_build/html/04_ql-guide.html#sort-operator

For example:

rasql -q 'select encode(SORT raster2D ALONG 0  AS i BY raster2D[i[0], 0:0], "csv") from test_mr as raster2D' --out string

Executing retrieval query... rasdaman error 412: Execution error 412 in line 0, column 0, near token : Value expression must be either of type atomic or complex.

rasql -q 'select encode(SORT raster2D ALONG time  AS i BY raster2D[i[0], 0:0], "csv") from test_mr as raster2D' --out string
Executing retrieval query... rasdaman error 347: Execution error 347 in line 1, column 29, near token ALONG: Name of the axis doesn't correspond with any defined axis name of the type.

 rasql -q 'select encode(sort c along 1 as i by c[*:*,i[0]], "csv") from test_mr as c' --out string
Executing retrieval query... rasdaman error 412: Execution error 412 in line 0, column 0, near token : Value expression must be either of type atomic or complex.

In the doc, DESC is put wrongly at the end in the examples, e.g.

SORT raster2D ALONG 0 AS n BY add_cells(raster2D[n[0], 1:1]) DESC
SORT raster3D ALONG 1 AS i BY max_cells(raster3D[*:*, i[0], *:*]) DESC

The syntax defines:

sortExp: SORT generalExp ALONG sortAxis AS sortAxisIterator [listingOrder] BY cellExp

[Dimitar Misev]

The doc examples should use the demo collections mr2 or rgb, not test_mr from the systemtest. And ideally they should run without errors.

[Bang Pham Huu]

Note: There is a big difference in the results of a rasql query using sort operator:

SELECT encode(SORT c ALONG 0 AS i ASC BY c[i[0],39], "jpeg" , "{\"metadata\":{\"resolution\":\"1\"},\"nodata\":[]}")  FROM test_mr AS c

Left is Ubuntu 20.04, right is centos 7

[Dimitar Misev]

Are you sure you have look at the right output on CentOS 7? It looks like no sorting was done at all and it returns the original image.