International Business Machines Corporation

Aviv Kuvent

Asaf Levy

Yariv Bachar

Konstantin Muradov

Alon Horowitz

For maintaining consistency for a cache that contains dependent objects in a computing environment, object dependencies for cached objects are managed by defining and maintaining object dependency lists for each one of the cached objects for identifying objects upon which the cached objects are dependent. Maintaining cache consistency for 2 types of cache eviction policies is supported by maintaining an object dependency lists for each one of the cached objects for identifying objects dependent upon the cached object. Each of the objects in an object dependency list is updated when the object is updated.

Maintaining cache consistency in a cache for cache eviction policies supporting dependencies

A selective tuple versioning is used on a files system for preserving past states of file system nodes by adding a bitmap to a row for a node within a file system table for preserving the past state of the node in a file system, receiving a request for updating the node along with a node identification (ID) and associated attributes of the node needing to be updated, generating a second time value indicating the time of the updating, and duplicating the row for the node into a new row in the file system table with an end time set equal to the second time value if the bit in the bitmap for the node is set.

Preserving past states of file system nodes

A multiplicity of nodes are represented with a unique node identification (ID) and range ID for both enabling the database tree to be modified and identifying descendants of each of the plurality of nodes in a single query.

Representing dynamic trees in a database

Selective tuple versioning is used on a file system providing file system snapshots by, receiving a request for updating at least one node and at least a node identification (ID) and associated attributes of the plurality of nodes, generating a new snapshot timestamp indicating the time of the updating, duplicating one of a plurality of rows of the nodes in the file system table into a new one of the rows of the file system table with an end time set equal to a new snapshot timestamp if the snapshot has the snapshot timestamp that is greater than a start time and less than the end time of the nodes, and updating the rows of the nodes in the file system table according to the update request, wherein the start time of the nodes is set equal to the new snapshot timestamp.

Preserving a state using snapshots with selective tuple versioning

For preserving past states of file system nodes, selective tuple versioning on a file system table is used by adding a bitmap to a row for a node within a file system table for preserving the past state of the node in a file system. A request is received for updating the node along with a node identification and associated attributes of the node needing to be updated. A second time value indicating the time of the updating is generated. The row for the node is duplicated into a new row in the file system table with an end time set equal to the second time value if the bit in the bitmap for the node is set. The row associated with the node is updated according to the update request.

Selective tuple versioning is used on a file system providing file system snapshots using selective tuple versioning for maintaining the state of the file system. The selective tuple versioning works by adding a snapshot table to associate with a file system table by storing a timestamp and a snapshot identification (ID) relating to a snapshot created for preserving past nodes in the file system.

Persistent iteration is performed in stages on nodes arranged according to a node identification (ID) that is increasing in order under a parent node in database tree structure. While performing the persistent iteration, storing a start node ID of the node where the persistent iteration commenced, a current node ID of the node that is undergoing the persistent iteration, a parent node ID of the node that is undergoing the persistent iteration, and a numerical value representing the current level and all levels greater than the current level of nodes that are undergoing the persistent iteration. Upon completion of the persistent iteration on the nodes that are the children of the node with the parent node ID, returning to the first node among the children of the node with the parent node ID, as ordered by increasing node ID, and performing the persistent iteration for children nodes of each node.

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Raanana, Israel

Aviv Kuvent