Compact sparse column groups

A method comprising:

• receiving a search query from a client device, the search query specifying a value of an attribute of an item listed on a network-based online marketplace;
• searching, by one or more computer processors, a database of items listed on the network-based online marketplace, the searching including accessing an index for the database, the accessing of the index including accessing a first data representation, the first data representation including an identifier corresponding to the value of the attribute of the item that is present in the index, determining whether the identifier is present in the index, and based on a determination that the identifier is present in the index, accessing a second data representation, the second data representation including a blob of data corresponding to the identifier based on one or more variable length codes, wherein the blob of data comprises an array of bytes that interleaves bytes of a first data element of a plurality of non-contiguous data elements with one or more bytes of a second data element of the plurality of non-contiguous data elements;
• generating a table based on accessing the second data representation, wherein the first data element of the plurality of non-contiguous data elements comprises an array of bytes that is included in the table that has been augmented with a plurality of continuation bits corresponding to each byte in the array of bytes;
• communicating the generated table for display at the client device or a different device;
• and
• in response to the search query, communicating a result of the searching of the database for display at the client device, the result comprising a listing for the item on the network-based online marketplace corresponding to the blob of data.

A non-transitory machine-readable medium comprising a set of instructions that, when executed by a processor, causes the processor to perform operations comprising:

• receiving a search query from a client device, the search query specifying a value of an attribute of an item listed on a network-based online marketplace;
• searching a database of items listed on the network-based online marketplace, the searching including accessing an index for the database, the accessing of the index including accessing a first data representation, the first data representation including an identifier corresponding to the value of the attribute of the item that is present in the index, determining whether the identifier is present in the index, and based on a determination that the identifier is present in the index, accessing a second data representation, the second data representation including a blob of data corresponding to the identifier based on one or more variable length codes, wherein the blob of data comprises an array of bytes that interleaves bytes of a first data element of a plurality of non-contiguous data elements with one or more bytes of a second data element of the plurality of non-contiguous data elements;
• generating a table based on accessing the second data representation, wherein the first data element of the plurality of non-contiguous data elements comprises an array of bytes that is included in the table that has been augmented with a plurality of continuation bits corresponding to each byte in the array of bytes;
• communicating the generated table for display at the client device or a different device;
• and
• in response to the search query, communicating a result of the searching of the database for display at the client device, the result comprising a listing for the item on the network-based online marketplace corresponding to the blob of data.