Salesforce Com, Inc.

Salesforce, Inc.

Punit B Shah

Rama Krishna Korlapati

Rui Zhang

Mark Wilding

Patrick James Helland

James E Mace

Nathaniel Wyatt

Subho Sanjay Chatterjee

Serge Philippe Rielau

Jeffrey Ira Cohen

Douglas Doole

Yi Xia

Prateek Swamy

Prashasthi Prabhakar

Dominique Jeremy Evans

David Gershuni

Mikhail Lychagin

Techniques are disclosed relating to updating a database schema. A computer system may store database schema versions for a database schema. A given schema version may have an active state or one of multiple non-active states. One of the schema versions may be a first schema version that is in the active state and the remaining schema versions may be in the non-active states. The computer system may receive updates to apply to the database schema. The computer system may transition a second schema version from a first non-active state that does not permit structural or content updates to a second non-active state that permits structural and content updates. The computer system may apply the updates to the second database schema version and then transition the second database schema version into the active state and the first database schema version into the first non-active state.

Database object lifecycle states

Techniques are disclosed that relate to manipulating a chain of database objects without locking the chain. A computer system may maintain a chain that orders a set of database objects stored in a cache of the computer system. The computer system may receive a set of requests to perform database transactions. Based on those received set of requests, the computer system may determine to perform a plurality of chain operations that involve modifying the chain. The computer system may perform two or more of the plurality of chain operations at least partially in parallel using a set of atomic operations without acquiring a lock on the chain.

Mechanisms for maintaining chains without locks

Methods, computer readable media, and devices for identifying and preventing invalid memory access. A method may include defining a dynamic scope for an operation, receiving a request to allocate a portion of the range of shared memory, allocating a monotonically increasing portion of the range of shared memory such that a subsequent request to allocate memory is allocated a different portion of the range of shared memory, receiving a request to deallocate the allocated portion of the range of shared memory, deallocating the allocated portion of the range of shared memory by protecting the deallocated portion of the range of shared memory from any subsequent access, and in response to an access of the protected deallocated portion of the range of shared memory by one of the one or more threads or processes of the operation, trapping and terminating the one thread or process.

Identifying and preventing invalid memory access

Systems and methods provide multi-version concurrency control of database records with uncommitted transactions. The system and methods may include receiving a query regarding a transaction counter number. When a transaction header identifying data is updated with the assigned transaction counter number, the updated transaction header may be used in identifying data as an instance of multiversion concurrency control information by the received query. A key lookup may be performed, and when the key lookup encounters an uncommitted row for a transaction number, a corresponding transaction header identifying data to identify a data array element to determine whether the transaction number is committed, and determining the transaction counter number when the transaction number is committed. The transaction counter number may be stamped on the row version record when it is determined that the row is committed.

Multiversion concurrency control of database records with uncommitted transactions

Techniques are disclosed relating to concurrently processing transactions. A computer system may maintain a database table having a plurality of versions. Each of the versions may identify a corresponding portion of the database table that transactions associated with that version are permitted to access. The computer system may receive a first request to perform a first transaction to modify a definition of the database table. The computer system may receive a second request to perform a second transaction to modify data stored in the database table. In response to determining that the first and second transactions are associated with different versions of the plurality of versions, the computer system may concurrently process the first and second transactions.

Version-based table locking

Techniques are disclosed relating to testing application code. A computer system, in various embodiments, receives application code to be tested by the computer system and separate information defining actions to be performed at specified locations within the application code. In various embodiments, the computer system executes the application code in a test environment in which the actions defined by the separate information are retrieved and performed by a plurality of threads of the application code at the specified locations to control flow of the plurality of threads through the application code. In some embodiments, a first one of the plurality of threads is operable to perform at least one of the actions to control the flow of a second one of the plurality of threads.

Concurrency testing

Caching runtime plan data that is determined not to change for different invocations of a query plan. In some embodiments, a computing system accesses information that specifies a query plan generated for a first database query and generates a first runtime plan for the first database query based on the query plan. In some embodiments, the system caches information generated for the first runtime plan that is determined not to change for different invocations of the query plan. For example, transformation code may include separate functions for mutable and immutable state. In some embodiments, the system retrieves and uses the cached information to generate a second runtime plan for a second database query. Disclosed techniques may improve performance of query plan transformations that hit in the runtime plan cache.

Growing community of inventors

Castro Valley, CA, United States of America

Punit B Shah