Deterministic mapping and uniform routing of items to physical resources using hash values

A computer implemented method, comprising:

• receiving a string identifier, identifying an item to be assigned to one of a plurality of physical resources;
• applying a hashing function to the string identifier to obtain a numeric hash value uniformly distributed over a hash value space comprising a defined range of values;
• downscaling the numeric hash value into a reduced value space of bucket identifiers to obtain a downscaled value corresponding to a selected bucket identifier, each bucket identifier corresponding to a range of numeric hash values, the reduced value space of bucket identifiers having fewer values than the hash value space;
• deterministically mapping the selected bucket identifier to one of the plurality of physical resources;
• detecting a resizing input indicative of a change in the plurality of physical resources from a current number of physical resources to a changed number of physical resources;
• re-assigning a bucket identifier from a physical resource in the current number of physical resources to a different physical resource in the changed number of physical resources;
• identifying a start of a particular range of numeric hash values corresponding to the re-assigned bucket identifier based on a group index value and a bucket size;
• identifying an end of the particular range of numeric hash values based on the start of the particular range of numeric hash values and the bucket size;
• retrieving items having numeric hash values in the particular range of numeric hash values;
• and
• moving the retrieved items to the different physical resource.

A computer system, comprising:

• at least one processor;
• and
• memory storing instructions executable by the at least one processor, wherein the instructions, when executed, cause the computer system to:
• receive a string identifier, identifying an item to be assigned to one of a plurality of physical resources;
• apply a hashing function to the string identifier to obtain a numeric hash value uniformly distributed over a hash value space comprising a defined range of values;
• deterministically downscale the numeric hash value into a reduced value space of bucket identifiers to obtain a downscaled value corresponding to a selected bucket identifier, each bucket identifier corresponding to a range of numeric hash values, the reduced value space of bucket identifiers having fewer values than the hash value space;
• deterministically map the selected bucket identifier to one of the plurality of physical resources;
• detect a resizing input indicative of a change in the plurality of physical resources from a current number of physical resources to a changed number of physical resources;
• re-assign a bucket identifier from a physical resource in the current number of physical resources to a different physical resource in the changed number of physical resources;
• identify a start of a particular range of numeric hash values corresponding to the re-assigned bucket identifier based on a group index value and a bucket size;
• identify an end of the particular range of numeric hash values based on the start of the particular range of numeric hash values and the bucket size;
• retrieve items having numeric hash values in the particular range of numeric hash values;
• and
• move the retrieved items to the different physical resource.