Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: A system such as a database management system determines a rule to impose sorted order upon a column without applying a sorting algorithm to the column and stores the rule to be applied to sort the column. In an embodiment, a permutation is the rule. The column, in an embodiment, is a column of a database table. In some cases, the rule is used to efficiently impose a correct sorted order on a subset of unsorted columns without the use of a sorting algorithm. In some cases, the rule is generated based at least in part on another column that is sorted using a sorting algorithm such as quicksort.

Abstract: Late encoding binding can be applied to data added to a data set according to the encoding history for the data set. When a request to add data is received, an evaluation of the encoding history can determine whether a currently specified encoding for the data can be changed. If changeable, a different encoding scheme for the data may be identified and the data added to the data set according to the different encoding scheme.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for tracking memory usage. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. The MUT initiates a free process for a memory chunk. A current generation of the memory chunk is determined. The MUT determines whether the mapping element's generation precedes the current generation. If the mapping element's generation is old, the MUT treats the long-living rollover account as the owner of the memory chunk to be freed and if the current generation and the mapping element's generation match, then the MUT considers the owner associated with the mapping element as the owner of the chunk. The MUT then adjusts the balance of the determined memory account and/or sub-account and the balance of the mapping element by the freed memory amount.

Abstract: This application is directed to communicating vehicle data via a vehicle data feed server that is communicatively coupled to a plurality of vehicles. A plurality of credentials and associated access levels are stored in a database of the vehicle data feed server. The vehicle data feed server receives a plurality of real-time vehicle data flows from the vehicles. These real-time vehicle data flows are optionally associated with the credentials based on the associated access levels. Upon receiving from a user of a client device a user credential and a vehicle data request, the vehicle data feed server determines whether the user is authorized to access vehicle data that is associated with the user credential and includes a subset of the real-time vehicle data flows. The subset of the real-time vehicle data flows is forwarded to the client device when the user is authorized to access the vehicle data.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: A first column of a first database table may be transferred to a second table in a combined truncate and append operation in a transaction that may be atomic and reversible. References data for the first column may be removed from the first table and added to the second table. The combined operation may be reversed by removing, from the second table, references to blocks of data added to the second table prior to commencing the combined operation. A second column corresponding on a row-by-row basis to the first column may be added to the second table, where the data is indicative of visibility of data in the first column to other transactions on the second table.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for precisely tracking memory usage in a multi-process computing environment. One of the methods includes implementing an instance of a memory usage tracker (MUT) in each process running in a node of a computer system. A MUT can maintain an account of memory usage for each of multiple logical owners running on a process on which the MUT is running. The MUT can determine an actual memory quota for each owner, and enforce the actual memory quota of the owner. Enforcing the actual memory quota of the owner can include receiving each memory allocation request, checking each allocation request and a current state of the account against the actual quota, approving or rejecting each allocation request, communicating the approval or rejection to an underlying memory manager, and updating the owner account for each approved allocation request.

Abstract: Data movement driven placement of data in a distributed database is disclosed. A set of one or more queries anticipated to be performed with respect to a data set is received. A set of statistics associated with the data set is received. The set of queries and the statistics are used to explore algorithmically a search space of distribution policy alternatives, to determine an optimal distribution policy to distribute data comprising the data set across a plurality of database servers.