Maintaining a shared cache that has partitions allocated among multiple nodes and a data-to-partition mapping

A method for managing data, the method comprising the steps of:

• allocating a plurality of partitions of a shared cache, wherein said plurality of partitions include a partition in each of a set of two or more nodes of a multiple node system;
• establishing a mapping between the plurality of partitions and a plurality of data items;
• and
• in response to a request for a particular data item by a first node of said multiple node system, performing the steps of
• determining which partition of said plurality of partitions corresponds to the particular data item based on said mapping;
• determining whether the particular data item currently resides in said corresponding partition;
• if the particular data item does not currently reside in said corresponding partition, then loading a copy of the particular data item into the corresponding partition;
• and
• providing the particular data item from the corresponding partition to the first node;
• wherein each partition of said plurality of partitions maintains lock structures for data items that correspond to the partition based on the mapping;
• and
• wherein the method includes gathering information from each partition of the plurality of partitions to construct wait-for-graphs to perform deadlock detection.

A method for managing data, the method comprising the steps of:

• allocating a plurality of partitions of a shared cache, wherein said plurality of partitions include a partition in each of a set of two or more nodes of a multiple node system;
• establishing a mapping between the plurality of partitions and a plurality of data items by performing a hash operation on hash keys to produce hash values, wherein at least a portion of the hash keys are identifiers associated with persistent storage devices and the mapping is based on the hash values;
• and
• in response to a request for a particular data item by a first node of said multiple node system, performing the steps of
• determining which partition of said plurality of partitions corresponds to the particular data item based on said mapping;
• determining whether the particular data item currently resides in said corresponding partition;
• if the particular data item does not currently reside in said corresponding partition, then loading a copy of the particular data item into the corresponding partition;
• and
• providing the particular data item from the corresponding partition to the first node.

A method for managing data, the method comprising the steps of:

• allocating a plurality of partitions of a shared cache, wherein said plurality of partitions include a partition in each of a set of two or more nodes of a multiple node system;
• establishing a mapping between the plurality of partitions and a plurality of data items;
• and
• in response to a request for a particular data item by a first node of said multiple node system, performing the steps of
• determining which partition of said plurality of partitions corresponds to the particular data item based on said mapping;
• determining whether the particular data item currently resides in said corresponding partition;
• if the particular data item does not currently reside in said corresponding partition, then loading a copy of the particular data item into the corresponding partition;
• and
• providing the particular data item from the corresponding partition to the first node;
• wherein recovery from failure of a particular partition of said plurality of partitions includes recovering a data item that resided in said particular partition based on a current version of the data item from a node-private cache of a surviving node of said multiple node system.

A method for managing data, the method comprising the steps of:

• allocating a plurality of partitions of a shared cache, wherein said plurality of partitions include a partition in each of a set of two or more nodes of a multiple node system;
• establishing a mapping between the plurality of partitions and a plurality of data items;
• and
• in response to a request for a particular data item by a first node of said multiple node system, performing the steps of
• determining which partition of said plurality of partitions corresponds to the particular data item based on said mapping;
• determining whether the particular data item currently resides in said corresponding partition;
• if the particular data item does not currently reside in said corresponding partition, then loading a copy of the particular data item into the corresponding partition;
• and
• providing the particular data item from the corresponding partition to the first node
• wherein:
• the multiple node system includes a plurality of nodes;
• a node of said plurality of nodes includes a checkpoint associated with a redo log;
• and
• the method further comprises preventing the node from advancing the checkpoint past a position in the redo log associated with a particular data item until the partition, of said plurality of partitions, that is associated with the particular data item has written the particular data item to persistent storage.

A method for managing data, the method comprising the steps of:

• allocating a plurality of partitions of a shared cache, wherein said plurality of partitions include a partition in each of a set of two or more nodes of a multiple node system;
• establishing a mapping between the plurality of partitions and a plurality of data items;
• and
• in response to a request for a particular data item by a first node of said multiple node system, performing the steps of
• determining which partition of said plurality of partitions corresponds to the particular data item based on said mapping;
• determining whether the particular data item currently resides in said corresponding partition;
• if the particular data item does not currently reside in said corresponding partition, then loading a copy of the particular data item into the corresponding partition;
• and
• providing the particular data item from the corresponding partition to the first node;
• wherein recovery from failure of a particular partition of said plurality of partitions includes merging redo information from a plurality of nodes in said multiple node system.