Remote querying of inverted indexes

A computerized method for querying data in a disaggregated storage tier of a database, the method comprising:

• receiving a query for data contained in the disaggregated storage tier, the query being received from a client and requiring identification of a documentin the disaggregated storage tier that have a term satisfying an expression;
• in response to the receiving of the query:
• accessing a first inverted index in a first data segment stored in the disaggregated storage tier and, from the first inverted index, identifying a first document in the first data segment having a first term that satisfies the expression and identifying a second document in the first data segment having a second term that satisfies the expression;
• accessing a second inverted index in a second data segment stored in the disaggregated storage tier and, from the second inverted index, identifying an indication, stored within the second inverted index, that the second term was removed from the second document;
• compiling a list of identifiers for documents containing the term, the list of identifiers including a first identifier corresponding to the first document and excluding a second identifier corresponding to the second document, the exclusion of the second identifier being based on the indication that the second term was removed from the second document;
• and
• return the list of identifiers to the client.

A non-transitory computer-readable storage medium storing instructions executable by a processing apparatus to perform operations comprising:

• writing a first data segment to a disaggregated storage tier of a database, the first data segment being an immutable segment comprising a data file and an inverted index file, the data file comprising a plurality of documents each having a document identifier, the inverted index file having a plurality of terms corresponding to terms in the plurality of documents, each of the plurality of terms in the inverted index file having associated therewith at least one document identifier and for each document identifier a plus-indication or a minus-indication, the plus-indication indicating that the term was added to a version of a document corresponding to the document identifier that resides in the first data segment, the minus-indication indicating that, for the version of the document residing in the first data segment, the term was removed from an earlier version of the document;
• receiving a query for the database, the database comprising the first data segment and a second data segment, the query being received from a client and requiring identification of a document in the disaggregated storage tier that have a term satisfying an expression;
• responsive to the receipt of the query:
• accessing a first inverted index in the first data segment and, from the first inverted index, identifying a first document in the first data segment having a first term that satisfies the expression and a second document in the first data segment having a second term that satisfies the expression;
• accessing a second inverted index in the second data segment and, from the second inverted index, identify an indication, stored within the second inverted index, that the second term was removed from the second document;
• compiling a list of identifiers for documents containing the term, the list of identifiers including a first identifier corresponding to the first document and excluding a second identifier corresponding to the second document, the exclusion of the second identifier being based on the indication that the second term was removed from the second document;
• and
• generating a response to the query using the list of identifiers.