Paged column dictionary

One or more computer-readable storage media storing structured data usable by one or more processors to load dictionary blocks for a dictionary into memory, the structured data stored on the computer-readable storage media comprising computer executable instruction that, when executed by a processor of a computer, cause the computer to perform operations comprising:

• defining multiple dictionary blocks for a dictionary comprising string values associated with corresponding value identifiers (IDs) for dictionary compression, each of the multiple dictionary blocks storing at least some of the string values;
• defining one or more directory value ID blocks for a value ID directory comprising value IDs for the multiple dictionary blocks, each of the one or more directory value ID blocks storing at least some of the last value IDs;
• receiving a request for an entry of the dictionary having multiple dictionary blocks, wherein the dictionary stores string values associated with corresponding value IDs for dictionary compression;
• searching the value ID directory using a value ID associated with the request;
• selecting a dictionary block of the multiple dictionary blocks as responsive to the request by comparing the value ID to a plurality of value IDs of the value identifier directory to identify the dictionary block as comprising dictionary information for the value ID;
• loading the selected dictionary block from persistent storage into memory in response to determining that the value ID is present in the dictionary block;
• searching the selected dictionary block that has been loaded into memory for the value ID;
• identifying a string value corresponding to the value ID;
• and
• returning the string value in response to the request.

A system comprising:

• one or more processors;
• a memory coupled to the one or more processors;
• and
• one or more computer-readable media storing computer executable instructions that, when executed by the one or more processors, cause the system to perform operations comprising:
• constructing a value identifier (ID) directory in memory for a dictionary having multiple dictionary blocks, each dictionary block comprising a plurality of value blocks, each value block comprising a value ID and comprising a plurality of string values;
• receiving a request for an entry of the dictionary having multiple dictionary blocks, wherein the dictionary stores string values associated with corresponding value IDs for dictionary compression;
• searching the value ID directory using a value ID associated with the request;
• selecting a dictionary block of the multiple dictionary blocks as responsive to the request by comparing the value ID to a plurality of value IDs of the value identifier directory to identify the dictionary block as comprising dictionary information for the value ID;
• loading the selected dictionary block from persistent storage into memory in response to determining that the value ID is present in the dictionary block;
• searching the selected dictionary block that has been loaded into memory for the value ID;
• identifying a string value corresponding to the value ID;
• and
• returning the string value in response to the request.