khannaekta commented on a change in pull request #401: DL: fix
default_buffer_size calculation
URL: https://github.com/apache/madlib/pull/401#discussion_r289137967
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File path: src/ports/postgres/modules/internal/db_utils.py_in
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@@ -93,3 +92,28 @@ def is_col_1d_array(source_table, col_name):
""".format(col_name, source_table)
result = plpy.execute(query)
return result[0]["n_y"]
+
+#
------------------------------------------------------------------------------
+# This function runs postgres array_ndims function to get
+# the dimension of an array. For example if it is a 3
+# dimension array it will be an array with 3 elements
+# like [32,32,3].
+def get_ndims(source_table, col_name):
+ array_ndims = plpy.execute("SELECT array_ndims({0}) AS ndims FROM {1}".
+ format(col_name, source_table))[0]['ndims']
+
+ return array_ndims
+
+# This function is to calculate the total `length` of a
+# multi dimentional array. For example, if an array is
+# with 3 dimentions and ndims=[32,32,3], this function
+# will return the product of them, which is 32*32*3
+def get_product_of_dimensions(source_table, col_name):
+ ndims = get_ndims(source_table, col_name)
+ dimension_product = 1
+ for i in range(1, ndims + 1):
+ array_upper_query = "SELECT array_upper({0}, {1}) AS dimension from
{2}".format(col_name, i, source_table)
Review comment:
We can also call `get_col_dimension(col_name, source_table, i)` which calls
the same query internally.
But, will leave it upto you whichever way you prefer.
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