Salesforce, Inc.

Salesforce Com, Inc.

Aditya Dharmanand Shetty

Thomas Fanghaenel

Rohit Agrawal

Terry Chong

Kaushal Mittal

Vaibhav Arora

Techniques are disclosed relating to index metadata that is usable for accessing multi-level data structures. A computer system may operate a database, including maintaining a set of records having a set of corresponding keys. The computer system may create multi-level data structures that facilitate key range lookups against those records. A given multi-level data structure may store key information indicative of a subset of the corresponding keys. The computer system may create separate index metadata that is usable for accessing the multi-level data structures. The index metadata may specify indications of key information that is stored in the multi-level data structures and locations of the multi-level data structures. The computer system may perform a key range lookup that includes using the index metadata to determine a particular set of the multi-level data structures whose key information corresponds to a key range of the key range lookup.

Index for multi-level data structures

Techniques are disclosed relating to merge operations for multi-level data structures, such as log-structured merge-trees (LSM trees). A computer system may store, in a database, a plurality of files as part of an LSM tree and a plurality of database key structures. A given one of the plurality of database key structures may indicate, for a corresponding one of the plurality of files, a set of key ranges derived from database records that are included in the corresponding file. The computer system may determine, using ones of the plurality of database key structures, a key range overlap that is indicative of an extent of overlap of key ranges from a set of the plurality of files with respect to a particular key range. Based on the determined key range overlap, the computer system may assign a priority level to a merge operation that involves the set of files.

Merges using key range data structures

Techniques are disclosed relating to compressing database keys. A computer system may receive a request to write a database record to a storage medium. The database record may include a database key and a corresponding data value. The computer system may compress the database key by replacing a portion of the database key with particular data that identifies a location of a reference database key and an amount of similarity determined between the database key and the reference database key. The computer system may write the database record to the storage medium. The database record may include the compressed database key and the corresponding data value.

Database key compression

Techniques are disclosed relating to building an in-memory multi-level data structure useable to determine presence or absence of key ranges in files consisting of database records. In various embodiments, a computer system operates a database, including maintaining a set of records having a set of corresponding keys that are accessible in key-sorted order and generates a multi-level data structure that facilitates key range lookups against the set of records. The generating may include accessing ones of the set of keys in key-sorted order and determining, for a particular accessed key that includes a set of characters, an intermediate level within the multi-level data structure and a subset of the characters of the particular accessed key for insertion. The computer system may insert, starting at the intermediate level, information that identifies the subset of characters, with the inserting being performed without traversing any levels before the intermediate level.

Building of tries over sorted keys

Techniques are disclosed relating to determining whether a set of database schemas are different. A computer system may receive a request to create a snapshot for a set of data stored in a database having a first database schema. In response to receiving the request, the computer system may create the snapshot for the set of data. As part of the creating, the computer system may generate, based on the first database schema, a first hierarchy of hash values that includes a first root hash value for the first database schema. The first hierarchy of hash values may be usable to determine whether the first database schema is different from a second database schema. The computer system may include the first hierarchy of hash values with the snapshot.

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San Francisco, CA, United States of America

Aditya Dharmanand Shetty