Class / Patent application number | Description | Number of patent applications / Date published |
707683000 | Redo (i.e., roll forward) | 20 |
20100121824 | DISASTER RECOVERY PROCESSING METHOD AND APPARATUS AND STORAGE UNIT FOR THE SAME - A technique capable of constructing a disaster recovery system reduced in performance degradation of a primary system is provided. The technique includes a step of conducting synchronous writing of log information into a secondary storage subsystem in a secondary system when a write request received from a host computer is a write request of log information, a step of temporarily storing a write request and conducting asynchronous writing into the secondary storage subsystem when the received write request is a write request of database data or status information, a step of modifying log information, data in a database area, and status information in the secondary storage subsystem according to contents of a write request received from a primary storage subsystem, and a step of recovering the database area according to contents of log information in a location indicated by the status information. | 05-13-2010 |
20100228701 | UPDATING BLOOM FILTERS - The present invention extends to methods, systems, and computer program products for updating Bloom filters. Embodiments of the invention facilitate more efficient use Bloom filters across multiple computers connected across a WAN (potentially having limited bandwidth and latency characteristics), such as, for example, computers located on different continents. The acceptability of false positives is leveraged by allowing the operation of removing items from a set to be batched and delayed. On the other hand, insert operations may be more latency sensitive as a delayed insert results in the semantic equivalent to a false negative. As such, additions to a set are processed in closer to real time to update Bloom filters. In some embodiments, Bloom filters are used to check set membership for electronic mail addresses. | 09-09-2010 |
20110060724 | DISTRIBUTED DATABASE RECOVERY - A method and apparatus for recovery a cluster database is provided. Database recovery is divided among a plurality of surviving database server instances in the cluster. A surviving instance is responsible for recovering data blocks to which the surviving instance is assigned. One form of block-to-instance assignment may be based on mastership of the blocks. If a data block is locked by a surviving instance at the time of failure, then no recovery of that data block may be necessary. Else, if a copy of a data block that is to be recovered is stored on a surviving node in the cluster, then one or more redo records are applied to that copy (if necessary). A redo record that corresponds to that data block might not need to be applied to the copy if the redo record reflects changes (to the data block) that are already reflected in the copy. | 03-10-2011 |
20110184918 | RECOVERY POINT DATA VIEW SHIFT THROUGH A DIRECTION-AGNOSTIC ROLL ALGORITHM - A method and system of recovery point data view shift through a direction-agnostic roll algorithm is disclosed. The method includes forming a data view around a recovery point, and shifting the data view around the recovery point through a direction-agnostic roll algorithm that uses at least one of a roll-forward algorithm to shift the data view to a time after the recovery point and a roll-backward algorithm to shift the data view to a time before the recover point. A data integrity may be determined to be consistent at the recover point by examining data and meta-data associated with the recovery point. The recovery point may be associated with one of an automatically generated event, a user definable event, and/or a prepackaged event. A marker data may be generated at the recovery point to enable the direction-agnostic roll algorithm to reduce a recovery time objective when an algorithm is applied. | 07-28-2011 |
20120005168 | Logical Recovery with Unbundled Transaction Services - This patent application relates to enhanced logical recovery techniques for redo recovery operations of a system with an unbundled storage engine. These techniques can be implemented by utilizing an enhanced logical recovery approach in which a dirty page table (DPT) is constructed based on information logged during normal execution. The unbundled storage engine can include a transaction component (TC) that is architecturally independent of a data component (DC). These techniques can enhance redo recovery operations by mitigating the resources needed to determine whether previously executed operations sent from the TC to the DC are to be repeated in response to a recovery-initiating event. This can include using the DPT to avoid fetching every data page corresponding to every previously executed operation received by the DC during recovery and/or pre-fetching data pages and/or index pages that correspond to PIDs in the DPT | 01-05-2012 |
20120239628 | TRACKING REDO COMPLETION AT A PAGE LEVEL - Embodiments are directed to implementing a transitional redo phase to allow pre-redo phase data access and to determining which data pages including unprocessed transactions are to be processed during a transitional redo phase. In an embodiment, a computer system initiates an analysis phase of a database recovery that scans a database transaction log and builds a dirty page table that includes pages corresponding to unprocessed data transactions. The computer system determines from the dirty page table which pages are to be processed during the transitional redo phase, before the final redo phase. The computer system processes the determined pages during the transitional redo phase, before the final redo phase is reached and, upon completion of the system transaction undo phase, makes available those pages that were processed during the transitional redo phase, as well as those database pages that are not scheduled for processing during the final redo phase. | 09-20-2012 |
20120330899 | AUTOMATIC FAILOVER CONFIGURATION WITH LIGHTWEIGHT OBSERVER - Techniques used in an automatic failover configuration having a primary database system, a standby database system, and an observer for preventing divergence among the primary and standby database systems while increasing the availability of the primary database system. In the automatic failover configuration, the primary database system remains available even in the absence of both the standby and the observer as long as the standby and the observer become absent sequentially. The failover configuration further permits automatic failover only when the observer is present and the standby and the primary are synchronized and inhibits state changes during failover. The database systems and the observer have copies of failover configuration state and the techniques include techniques for propagating the most recent version of the state among the databases and the observer and techniques for using carefully-ordered writes to ensure that state changes are propagated in a fashion which prevents divergence. | 12-27-2012 |
20130117237 | Distributed Database Log Recovery - Log entries are recorded in a data storage application (such as an in-memory database, etc.) for a plurality of transactions among nodes in a node hierarchy. The node hierarchy comprises master node having a plurality of slave nodes. Thereafter, at least a portion of the master node log entries are replayed until a first replay position is reached. Next, for each slave node, at least a portion of its respective log entries are replayed until the first replay position is reached (or an error occurs). Subsequently, replay of at least a portion of the log entries of the master node that are subsequent to the first replay position is initiated by the master node in parallel to at least a portion of the replaying by the slave nodes. Related apparatus, systems, techniques and articles are also described. | 05-09-2013 |
20130282666 | METHOD AND SYSTEM FOR IMPLEMENTING A REDO REPEATER - Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations. | 10-24-2013 |
20130282667 | METHOD AND SYSTEM FOR IMPLEMENTING A CONDITIONAL REDO REPEATER - Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations. | 10-24-2013 |
20140067767 | GENERATING AND APPLYING REDO RECORDS - Techniques for maintaining a cascading index are provided. In one approach, one or more branch node compression techniques are applied to the main index of a cascading index. In an approach, a Bloom filter is generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node. In an approach, a new redo record is generated in response to a merge operation between two levels of the cascading index. The new redo record comprises (a) one or more addresses of blocks that are affected by the merge operation, (b) data is that being “pushed down” to a lower level of the cascading index, and (c) one or more addresses of blocks that are written to storage as a result of the merge operation. | 03-06-2014 |
20140095452 | IN PLACE POINT-IN-TIME RECOVERY OF PLUGGABLE DATABASES - In an approach, a database server maintains a container database which comprises: one or more pluggable databases, a root database that stores an undo log for rolling back transactions on the consolidated database, and a redo log for replaying modifications to the container database. The database server restores a particular pluggable with a backup version that corresponds to a first point in time. The database server generates a clone database loaded with a backup version of the root database that corresponds to the first point in time. The database server applies the redo log to recover the particular pluggable database and the clone database to a second point in time that is later than the first point in time. The database server identifies, based on the clone database, one or more active transactions on the particular pluggable database. The database server rolls back the one or more active transactions. | 04-03-2014 |
20140122439 | DELETING RECORDS IN A MULTI-LEVEL STORAGE ARCHITECTURE - Deleting a data record from the second level storage or main store is disclosed. A look-up is performed for the data record in the first level storage, where the data record is defined by a row identifier. If the row identifier is found in the first level storage, a look-up is performed for an updated row identifier representing an update of the data record in the second level storage and the main store, the update of the data record being defined by an updated row identifier. If the updated row identifier is found in the second level storage, an undo log is generated from the first level storage to invalidate a row identifier of the row identifier. A flag is generated representing an invalid updated row identifier, and a redo log is generated to restore the data record in the first level storage. | 05-01-2014 |
20140258241 | ZERO AND NEAR-ZERO DATA LOSS DATABASE BACKUP AND RECOVERY - A method, system and computer program product for low loss database backup and recovery. The method commences by transmitting, by a first server to a third server, a copy of a database snapshot backup, the transmitting commencing at a first time. Then capturing, by the first server, a stream of database redo data, the capturing commencing before or upon transmitting the database snapshot backup, and continuing until a third time. The stream of database redo data is received by an intermediate server after which the intermediate server transmits the stream of database redo data to the third server. Now, the third server has the database snapshot backups and the database redo data. The third server can send to a fourth server all or portion of the database redo data to be applied to the copy of the database snapshot backup restored there to create a restored database. | 09-11-2014 |
20140279929 | DATABASE SYSTEM WITH DATABASE ENGINE AND SEPARATE DISTRIBUTED STORAGE SERVICE - A database system may include a database service and a separate distributed storage service. The database service (or a database engine head node thereof) may be responsible for query parsing, optimization, and execution, transactionality, and consistency, while the storage service may be responsible for generating data pages from redo log records and for durability of those data pages. For example, in response to a write request directed to a particular data page, the database engine head node may generate a redo log record and send it, but not the data page, to a storage service node. The storage service node may store the redo log record and return a write acknowledgement to the database service prior to applying the redo log record. The server node may apply the redo log record and other redo log records to a previously stored version of the data page to create a current version. | 09-18-2014 |
20140279930 | FAST CRASH RECOVERY FOR DISTRIBUTED DATABASE SYSTEMS - A distributed database system may implement fast crash recovery. Upon recovery from a database head node failure, a connection with one or more storage nodes of a distributed storage system storing data for a database implemented by the database head node may be established. Upon establishment of the connection with the storage nodes, that database may be made available for access, such as for various access requests. In various embodiments, redo log records may not be replayed in order to provide access to the database. In at least some embodiments, the storage nodes may provide a current state of data stored for the database in response to requests. | 09-18-2014 |
20140279931 | SYSTEM-WIDE CHECKPOINT AVOIDANCE FOR DISTRIBUTED DATABASE SYSTEMS - A database system may maintain a plurality of log records at a distributed storage system. Each of the plurality of log records may be associated with a respective change to a data page. Upon detection of a coalesce event for a particular data page, log records linked to the particular data page may be applied to generate the particular data page in its current state. Detecting the coalesce event may be a determination that the number of log records linked to the particular data page exceeds a threshold. | 09-18-2014 |
20140365444 | TRACKING REDO COMPLETION AT A PAGE LEVEL - Embodiments are directed to implementing a transitional redo phase to allow pre-redo phase data access and to determining which data pages including unprocessed transactions are to be processed during a transitional redo phase. In an embodiment, a computer system initiates an analysis phase of a database recovery that scans a database transaction log and builds a dirty page table that includes pages corresponding to unprocessed data transactions. The computer system determines from the dirty page table which pages are to be processed during the transitional redo phase, before the final redo phase. The computer system processes the determined pages during the transitional redo phase, before the final redo phase is reached and, upon completion of the system transaction undo phase, makes available those pages that were processed during the transitional redo phase, as well as those database pages that are not scheduled for processing during the final redo phase. | 12-11-2014 |
20150355975 | METHOD AND APPARATUS FOR PROCESSING REDO DATA IN DATABASE - Embodiments of the present invention provide a method and an apparatus for processing redo data in a database, where the method includes: generating redo data according to a database modification operation, accordingly saving the redo data in a buffer allocated to each application thread, saving an identifier of the application thread in a time sequence queue after a time sequence queue lock is acquired; and determining that a data reading condition is satisfied, reading a sequence of the identifiers of the application threads from the time sequence queue, successively reading a piece of redo data from the buffer of each application thread corresponding to the identifier of each application thread in the time sequence queue, and writing the piece of redo data to a redo queue. Redo data processing efficiency can be improved by separating a time sequence queue from a data queue. | 12-10-2015 |
20160179978 | UNDO AND REDO OF CONTENT SPECIFIC OPERATIONS | 06-23-2016 |