Abstract: A database receives a query from a client for a database that has two segments. The query requires documents in the database having terms satisfying a criterion. Upon receiving the query, the system accesses a first inverted index in the first segment to find documents with terms that satisfy the expression. It identifies within the first segment first and second documents with first and second terms, respectively. Then, it accesses a second inverted index in the second segment and identifies an indication that the second term was removed from the second document. The database compiles a list of document identifiers, including the first document's identifier. The second document's identifier is excluded based on the removal indication. The list of document identifiers is used in generating a query response.

Abstract: To avoid inconsistencies caused by clock skew across data storage tiers, a point-in-time restore service creates a restore account, restores a partition of the database to its state at the designated point-in-time, including data from that time. A restored value is read from the data and a list is retrieved of segments written to a disaggregated storage tier by the existing partition. The disaggregated storage tier includes a first segment with a first value and a second segment with a second value, the values indicating their creation order. A first comparison is made between the restored value and the first value, and a second comparison is made between the restored value and the second value. Based on these comparisons, the first segment but not the second segment is copied to the restore account.

Abstract: To avoid inconsistencies caused by clock skew across data storage tiers, a point-in-time restore service creates a restore account, restores a partition of the database to its state at the designated point-in-time, including data from that time. A restored value is read from the data and a list is retrieved of segments written to a disaggregated storage tier by the existing partition. The disaggregated storage tier includes a first segment with a first value and a second segment with a second value, the values indicating their creation order. A first comparison is made between the restored value and the first value, and a second comparison is made between the restored value and the second value. Based on these comparisons, the first segment but not the second segment is copied to the restore account.

Abstract: According to examples, a cloud platform implementing a tiered storage that decouples Request Units from storage is disclosed. Data received from partitions that are characterized by corresponding partition keys is stored to the local storage medium of a virtual machine (VM) as hot data. The received data is formatted as immutable segments and stored to a disaggregated storage medium shared by a plurality of VMs. The immutable segments are grouped into sorted runs within the disaggregated storage medium and are further assigned to different levels. The hot data is deleted from a local storage medium when time-to-cold (TTC) criteria are met. The cold data can be accessed for document retrieval via a search key that includes a partition key and a documentID. Additional Request Units can be allocated or de-allocated for a portion of the cold data without moving the cold data.

Abstract: According to examples, a cloud platform implementing a tiered storage that decouples Request Units from storage is disclosed. Data received from partitions that are characterized by corresponding partition keys is stored to the local storage medium of a virtual machine (VM) as hot data. The received data is formatted as immutable segments and stored to a disaggregated storage medium shared by a plurality of VMs. The immutable segments are grouped into sorted runs within the disaggregated storage medium and are further assigned to different levels. The hot data is deleted from a local storage medium when time-to-cold (TTC) criteria are met. The cold data can be accessed for document retrieval via a search key that includes a partition key and a documentID. Additional Request Units can be allocated or de-allocated for a portion of the cold data without moving the cold data.