Abstract: Tracking changes to a document by defining a document record having a unique document record and comprising an index and a file name of the document, and defining a backup record for the document in a series of backups, which includes a timestamp for each backup, and a bitmask for the document. The bitmask has a single bit position for each document in the container which is set to a first binary value to indicate that the corresponding document is unchanged and a second binary value to indicate whether the document is changed or deleted. A primary query is received and resolved for the document by analyzing the document record to find the file name. A secondary query using the document record ID is resolved to find all tracked versions of the document, and the results are returned to the user in the form of a version history list.

Abstract: A method for processing data exactly once using transactional stream writes includes receiving, from a client, a batch of data blocks for storage on memory hardware in communication with the data processing hardware. The batch of data blocks is associated with a corresponding sequence number and represents a number of rows of a table stored on the memory hardware. The method also includes partitioning the batch of data blocks into a plurality of sub-batches of data blocks. For each sub-batch of data blocks, the method further includes assigning the sub-batch of data blocks to a buffered stream; writing, using the assigned buffered stream, the sub-batch of data blocks to the memory hardware; updating a storage log with an intent to commit the sub-batch of data blocks using the assigned buffered stream; and committing the sub-batch of data blocks to the memory hardware.

Abstract: Embodiments of the present description provide a data processing method and apparatus, and an edge device. A currently received message is written to a first area of a local disk, and upon writing the currently received message to the first area of the local disk, the currently received message is buffered to a cache. When an edge device is restarted, data in the cache may be restored according to data stored in the first area of the local disk.

Abstract: A system for storing and managing subscription information for a plurality of subscribers in a mobile communications network is provided. The system comprises a first database, a second database, and one or more processors. The processors are configured to receive a request relating to a subscriber, determine that the first database lacks a desired record relating to the subscriber, retrieve the desired record from the second database, write the retrieved desired record to the first database, and perform one or more functions related to the desired record according to the request. In some embodiments, the one or more processors are configured to predict a time of a potential occurrence of one or more future connections related to the plurality of subscribers and before the predicted time, copy one or more records related to the plurality of subscribers from the second database to the first database.

Abstract: In an example embodiment, a method comprises determining that a multipart upload request to upload a data object in separate object parts has been received by an object storage service; generating temporary keys for the separate object parts of the data object; storing the temporary keys in a temporary key data store; generating, based on the temporary keys, a multipart key entry for the data object, the multipart key entry comprising a multipart key that contains an object identifier identifying the data object and an inverse timestamp; and inserting the multipart key entry in a persistent key data store storing an ordered set of key entries in a position determined by the object identifier and the inverse timestamp.

Abstract: In an embodiment, a computer-implemented method comprises accessing a plurality of different computer program applications that are associated with a single account and retrieving data items that are associated with the account from each different application among the plurality of applications; identifying a subset of the data items comprising relevant data items, at least a first data item of the subset being associated with a first application of the plurality of applications, and at least a second data item being associated with a second application of the plurality of applications that is different than the first application; causing displaying, using a computer display device, an integrated view comprising at least the first data item and the second data item of the subset of the data items; receiving a first input specifying a first action associated with the first data item, and a second input specifying a second action associated with the second data item; in response to the first input, signaling th

Abstract: A computer implemented method is provided comprising receiving a group of transaction logs from a first database, allocating transaction logs from the group of transaction logs to a first queue and to a second queue, generating an end-of-group transaction log indicative of an end of the group of transaction logs, allocating the end-of-group log to the first queue and the second queue; replaying transaction logs from the first queue including the end-of-group transaction log allocated to the first queue, replaying transaction logs from the second queue including the end-of-group transaction log allocated to the second queue; and changing visibility of one or more transactions in response to replaying the end-of-group transaction log allocated to the first queue and the end-of-group transaction log allocated to the second queue. Related apparatus, systems, techniques and articles are also described.

Abstract: In a multitenant database, one or more supporting data tables are used to write and store tenant data. Based on the contextual data returning an indication of validity of a detected database transaction, various actions are performed. Data changes may be captured if no valid context is found. At runtime, triggers are used to set a valid context or fix mode context, and database operations causing the data corruptions are captured in a change tracking data structure. The captured data from the database operations include a primary key and an original value for each data change. The original value and primary key for each data change is used to nullify the unintended write.

Abstract: A system includes a plurality of clustered servers, a plurality of clients communicating with the plurality of clustered servers, and a grace database. Each of the plurality of clustered servers maintains a respective client recovery list. A client of the plurality of clients is configured to send a reclaim request to a server of the plurality of clustered servers. The grace database is configured to maintain an epoch value and a reclaim value. The epoch value indicates the current epoch, and the reclaim value indicates from which epoch reclaim is allowed. The server of the plurality of clustered servers is configured to maintain a client list and receive the reclaim request from the client. The client list indicates each client currently holding state on the server.

Abstract: Restoring data to a data store that suffered corrupted data over a time period is disclosed. A system may provide an interface to specify a time window and filter conditions for identifying corrupted data in an object in a data store, such as, but not limited to, a corrupted NoSQL table. Corrupted data is identified by applying the filter conditions to change logs for the data object (e.g., the No SQL table) in the data store. Repair operations are determined for individual items identified via the filter conditions. Identified corrupted data for items may be corrected, from change logs or backup data in some instances (e.g., data may be deleted, or updated or replaced with data from a backup of the data store when necessary).

Abstract: A system and method for recovering messages in a multi-node system that incorporates an active-active architecture with replicated databases is disclosed. The system comprises two or more computing nodes where each computing node includes brokers for processing local messages and a recovery broker for recovering messages from the replicated database when another node in the system fails. Each recovery broker competes with brokers on another node to acquire locks on database information. The recovery broker is successful if the network of brokers on the other node are unavailable and fail to obtain or retain locks on the database information. In this situation, the recovery broker can retrieve messages from the database information and pass the messages to other brokers on the same computing node for processing and completing any ongoing transactions.

Abstract: The data storage system according to certain aspects can implement table level database restore. Table level database restore may refer to restoring a database table and its related data without restoring the entire database. The data storage system may use table metadata index to implement table level restore. A table metadata index may be created for each table, e.g., during a backup of the database. The table metadata index for a table can include any type of information for restoring the table and its related data. Some examples of the type of information included in the table metadata index include the following: container for the table, table backup location, system data, table index, table relationships, etc. Table metadata index can make the restoring of tables fast and efficient by packaging information that can be used to restore a table and its related data in an easily accessible manner.

Abstract: A system including a plurality of nodes. Each node includes a pending operations list, an unstable operations list, and a hardware controller. The pending operations list can include operations that have not yet been executed on the node. The unstable operations list can include operations that have not yet been stored on non-volatile data storage. Each of the operations listed in the unstable operations list can include a listing of all other operations that must be executed prior to the operation being executed on each respective node. The hardware controller can be configured to execute at least one operation listed in the pending operations list, remove at least one executed operation from the pending operations list, and remove at least one operation from the unstable operations list.

Abstract: Methods and systems for providing a rewind of table data in a data management system include: storing a table having table data that defines a plurality of rows and a plurality of columns that define a plurality of cells; capturing change data associated with changes to at least one of the plurality of rows, the plurality of columns, and the plurality of cells; associating the change data with a transaction having a transaction identifier; storing the transaction and the change data in a change bus; retrieving the change data from the change bus based on a rewind request; performing a rewind of a subset of the changes by performing a reverse operation of the change data relating to the subset of changes and according to a reverse operation order; and outputting a clone of the table based on the rewind of the changes of the table.

Abstract: Various embodiments of the present technology generally relate to automated tools for tracking, recording, restoring and auditing transactions. In accordance with various embodiments, applications and servers can provide a variety of features including, but not limited to, behind the scene monitoring activity (transaction or business) and recording, persisting client activity, ubiquitous autosave, business workflow and approval lifecycles, error correction at the business level, management of the state of the transaction without the user having to manage the activity, tracking posted and unposted transactions (e.g., business state), and the like. The applications can communicate with a unified transaction engine that combines awareness of database transaction state along with business transaction states.

Abstract: A technique for processing a lock request is provided. A first lock server is a takeover lock server of a second lock server. The first lock server enters a silent state after learning that a fault occurs in the second lock server, where a silent range is a resource for which the second lock server has assigned permission. The first lock server receives an acquire lock request that is originally sent to the second lock server, and the first lock server assigns lock permission for a corresponding resource according to the acquire lock request if the second lock server has not assigned resource for the resource. By means of this solution, an impact range of a fault occurring in a lock server can be reduced, and stability of a lock management system is improved.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: Undo logging for persistent memory transactions may permit concurrent transactions to write to the same persistent object. After an undo log record has been written, a single persist barrier may be issued. The tail pointer of the undo log may be updated after the persist barrier, and without another persist barrier, so the tail update may be persisted when the next log record is written and persisted. Undo logging for persistent memory transactions may rely on inferring the tail of an undo log after a failure rather than relying on a guaranteed correct tail pointer based on persisting the tail after every append. Additionally, transaction version numbers and checksum information may be stored to the undo log enabling failure recovery.

Abstract: A method, a processing device, and a computer program product are provided. A truncate table command for truncating all or a subset of one or more rows of a database table is received from a first transaction executing on a processing device. At least one read operation on the truncated database table is performed for at least one transaction concurrent with the first transaction, wherein the truncated rows are visible to the at least one concurrent transaction and invisible to subsequent transactions. Storage units that store the truncated rows are reclaimed in response to completion of the at least one concurrent transaction.

Abstract: A computer implemented method is provided comprising receiving a group of transaction logs from a first database, allocating transaction logs from the group of transaction logs to a first queue and to a second queue, generating an end-of-group transaction log indicative of an end of the group of transaction logs, allocating the end-of-group log to the first queue and the second queue; replaying transaction logs from the first queue including the end-of-group transaction log allocated to the first queue, replaying transaction logs from the second queue including the end-of-group transaction log allocated to the second queue; and changing visibility of one or more transactions in response to replaying the end-of-group transaction log allocated to the first queue and the end-of-group transaction log allocated to the second queue. Related apparatus, systems, techniques and articles are also described.

Abstract: The method includes: receiving, by a first managed object device, a first transaction resource creation request that is sent by an application server and includes an identifier of a first to-be-operated resource, a first execution time, and a first to-be-executed operation; receiving, by a second managed object device, a second transaction resource creation request that is sent by the application server and includes an identifier of a second to-be-operated resource, a second execution time, and a second to-be-executed operation, where the first execution time and the second execution time are the same; successfully creating, by the first managed object device, a first transaction resource according to the first transaction resource creation request, and successfully creating, by the second managed device, a second transaction resource according to the second transaction resource creation request.

Abstract: A distributed system according to an exemplary embodiment includes first and second servers capable of executing the same application, wherein when a failure occurs in the application in the first server, the first server generates failure information identifying a cause of the failure in the application, and the second server performs failure prevention processing which is determined based on the failure information and intended to prevent a failure in the application.

Abstract: A database comprises a database interface and a database updater. The database interface enables a reading of a first set of information from the database. The database updater updates a second set of information in the database based at least in part on one or more conditions. The one or more conditions limit changes allowable to the first set of information from the database that occurred after the reading of the first set of information from the database.

Abstract: Embodiments for a system and method of performing restores of SQL database data, querying a backup history log to determine a sequence of full and incremental backups of the data, first restoring data from a full backup using a SQL volume shadow service (VSS) writer, placing the database into a recovering mode during the first restoring, and second restoring data from an incremental backup using a SQL virtual device interface (VDI) process while the database is in recovering mode until a stop signal is generated to form a hybrid restore process, where the stop signal comprises a STOPAT clause of the SQL VDI process that restores the database content until a given restore time.

Abstract: A solid state drive (SSD) with pseudo-single-level cell (pSLC) caching and a method of caching data in an SSD is disclosed. In one embodiment, the SSD includes a plurality of multibit NAND media devices arranged in one or more channels communicatively coupled to a memory controller. A first portion of the plurality of multibit NAND media devices is configured to operate as a pSLC cache and a second portion of the plurality of multibit NAND media devices is configured to operate as a multibit NAND media storage area. In one embodiment, the pSLC cache comprises a first area for a pSLC write cache and a second area for a pSLC read cache.

Abstract: Provided is a log management method in which, with a computer system provided with a processor, a memory, and a storage device, the processor executes a prescribed process and stores in the storage device a log which includes a description of the process, said method comprising a first step of the processor generating the log which includes the description of the prescribed process, a second step of the processor writing the log to a log file of the storage device, and a third step of the processor determining the end of the log region which stores the log and writing same to the log file of the storage device.

Abstract: A system and method for handling critical events in service delivery gateways. Events are defined that cause a transition from a master redundancy state to a standby redundancy state in service delivery gateways and a plurality of signal-routes are stored. Each signal-route is associated with one or more of the defined events. A first defined event is detected in the first service delivery gateway and causes a transition from the first master redundancy state to the first standby redundancy state in the first service delivery gateway and a change in a first signal-route from the plurality of signal-routes in the first service delivery gateway. The change in the first signal-route is advertised and a second service delivery gateway transitions from the first standby redundancy state to the first master redundancy state.

Abstract: A method for processing a fault of a lock server in a distributed system is disclosed, where the distributed system includes m lock servers, which locally store same lock server takeover relationship information. Lock servers in the distributed system that are not faulty receive a notification message, which carries information about a fault of a first lock server; after receiving the notification message, a second lock server determines that it is a takeover lock server of the first lock server according to the lock server takeover relationship information, and the takeover lock server enters a silent state; after receiving the notification message, a third lock server in the distributed system determines that it is not the takeover lock server of the first lock server according to the lock server takeover relationship information. After receiving a locking request, the third lock server allocates lock permission information according to the locking request.

Abstract: A database comprises a database interface and a database updater. The database interface receives a first set of information and a second set of information to be updated in the database. The database updater updates a second set of information in the database based at least in part on a condition that a first set of information in the database has been previously updated.

Abstract: The recovery of one or more transactions in a computing system in which one or more persistent systems are coupled via a bus to one or more processors. As an example, the persistent system may serve as at least part of the main memory of the computing system. The transaction might implement multi-versioning in which a record is not updated in place. Rather, each record is represented as a sequence of one or more record versions, each version having a valid interval during which the record version is considered to properly represent the record.

Abstract: Performing a transaction in the context of a computing system that has one or more persistent systems coupled to one or more processors over a bus. As an example, the persistent system may serve as at least part of the main memory of the computing system. The transaction might implement multi-versioning in which a record is not updated in place. Rather, each record is represented as a sequence of one or more record versions, each version having a valid interval during which the record version is considered to properly represent the record. As part of the transaction, post-commit processing information is generated to allow the computing system to recover in the event of a system failure.

Abstract: A method, system, and computer program product for adaptive high-performance database redo log synchronization. The method commences upon performing a write operation of a redo log entry, the write operation concluding with an indication of completion of the write operation of the redo log entry. Any number of committing processes may be waiting for the indication of completion, and upon indication of completion, then (using a first synchronization mode) the processes or proxy measures the waiting time as experienced by the committing processes (e.g., while waiting for the indication of completion of the write operation of the redo log entry). In some cases a second synchronization mode would introduce less latency than the first synchronization mode, so the system changes to a second synchronization mode. The system can also change mode when a predicted second mode waiting time is smaller than the measured waiting time.

Abstract: Extract, transform, and load application (ETL) complexity management framework systems and methods are described herein. The present disclosure describes systems and methods that reduce the complexity in managing ETL flow and correcting errant data that is subsequently identified. One or more methods include defining an ETL job definition, defining a data asset definition, defining a data asset dependency definition, receiving an ETL flow to provide execution of one or more ETL flow steps, providing retrieval of data from a source data asset, applying a data control to the source asset data, and producing an ETL job registration, a data asset status, a latest asset available date, a data asset consumer identifier, and a target data asset based on at least one of the ETL job definition, the data asset definition, the data dependency definition, and the source asset data.

Abstract: A database comprises a database interface and a database updater. The database interface receives a first set of information and a second set of information to be updated in the database. The database updater updates a second set of information in the database based at least in part on a condition that a first set of information in the database has been previously updated.

Abstract: Techniques for synchronization between data structures for original locks and mirror lock data structures are disclosed herein. The mirror lock data structures are being maintained during various scenarios including volume move and aggregate relocation, in order to preserve the non-disruptive persistent operation on storage initiated by clients. According to one embodiment, a storage node determines a plurality of data container locks to be synchronized to a partner node of the storage node and transfers metadata that indicates states of variables that represent the plurality of data container locks to the partner node in a batch. When a client initiates a data access operation that causes an attempt to modify a data container lock of the plurality of data container locks, the storage node sends a retry code to a client that prompts the client to retry the data access operation after a predetermined time period.

Abstract: A system and method for restoring a database are described. The method may comprise requesting to begin receiving notifications of transactions that occur in the database. In response to the request, notifications of a plurality of transactions that occur in the database may be received, and information specifying the plurality of transactions may be stored. The method may further comprise receiving user input requesting to restore the database to a previous state. In response, the stored information may be retrieved, and a graphical user interface indicating the plurality of transactions specified by the stored information may be displayed. The method may further comprise receiving user input to the graphical user interface selecting a particular transaction of the plurality of transactions. In response, the database may be restored to a particular point in time relative to a time at which the particular transaction occurred.

Abstract: A system for conducting memory transactions includes a non-volatile main memory and a memory buffer including a plurality of cache lines. Each of the cache lines includes content and one or more bits signifying whether a memory transaction corresponding to the content of the cache line has been performed to completion and whether the content of the cache line matches content of a corresponding location of the non-volatile main memory. When the one or more bits of a cache line of the plurality of cache lines signifies that the transaction has been performed to completion and the content of the cache line does not match the content of the corresponding location of the non-volatile memory, access to modify the content of the cache line is restricted until the content of the cache line is written to the corresponding location of the non-volatile main memory.

Abstract: A mass storage system employs a paging table for memory page redirection and maintains the paging table for power loss recovery (PLR) using a FIFO queue of paging table (L2P) segments to be written to non-volatile memory. The FIFO queue identifies a sequence of the L2P segments in conjunction with sequence number and marking data of the affected segments for recreating the paging table. Upon power failure, a power loss recovery (PLR) mechanism scans for the last segment written based on the FIFO queue. The PLR process recovers unwritten paging table entries by replaying the corresponding changes in the order defined by the sequence numbers. The recovery process continues for each sequence number in the current context, until the L2P information in the paging table is recreated to the point just prior to power loss.

Abstract: A logging system includes an event receiver and a storage manager. The receiver receives log data, processes it, and outputs a data “chunk.” The manager receives data chunks and stores them so that they can be queried. The receiver includes buffers that store events and a metadata structure that stores metadata about the contents of the buffers. The metadata includes a unique identifier associated with the receiver, the number of events in the buffers, and, for each “field of interest,” a minimum value and a maximum value that reflect the range of values of that field over all of the events in the buffers. A chunk includes the metadata structure and a compressed version of the contents of the buffers. The metadata structure acts as a search index when querying event data. The logging system can be used in conjunction with a security information/event management (SIEM) system.

Abstract: An image forming apparatus is described where restoration of unnecessary data is prevented, and a storage area of the image forming apparatus is effectively utilized. When an option to increase the storage capacity of the image forming apparatus is selected, data backed up by a backup unit is set as data to be restored by a restore unit. When the option to increase the storage capacity of the image forming apparatus is not selected, data indicated by data identification information as being required data is set as data to be restored by the restore unit from among the data backed up by the backup unit.

Abstract: Techniques described herein enable searching for multimedia content and for downloading or scheduling the recording of the multimedia content. The multimedia content may have been previously stored on one or more databases. The client device may download or schedule the recording of multimedia content in one step, for example, in one touch. When desired multimedia content is not available, the multimedia content is added to the client device's wish list. When the client device's does not have a wish list, the client device's wish list may be created on the spot. During the scheduling of the recording, a tag associated with the multimedia content is checked to determine whether the multimedia content is live or delayed. When the tag indicates the multimedia content is live or delayed, the client device prompts with a suggestion to add extra time to the end of the recording of the multimedia content.

Abstract: A system reserves and manages a hidden service partition through components of the hardware platform of a computing device. The hidden partition is not accessible by way of a host operating system on the computing device. A hardware platform controller provisions a portion of nonvolatile storage through configuration settings of the hardware platform controller. When the host system requests settings related to storage in the system, the request is routed through the interfaces of the hardware platform, and the hardware platform controller reports in accordance with the configuration settings, hiding the service partition. The hidden partition is dynamically modifiable through secure remote access to the hardware platform controller, not through the host system such as operating system or BIOS.

Abstract: According to one embodiment of the present invention, a system reduces re-reading of database logs by persisting long running transaction data. The system processes the database log records of the database transaction log; generates a snapshot of the database log records at periodic intervals, wherein each snapshot includes database log records for pending transactions; and in response to an interruption in processing of the database log records, utilizes a snapshot to restore database log records for the pending transactions and resume processing of the database transaction log from a position succeeding the database log records of the selected snapshot.

Abstract: A method for processing blocks of data in a file is provided. The method includes determining a plurality of blocks of data in the file for a compression process used for compressing data in the file. This process is iterated over all the plurality of blocks of data in the file. A block of data is read into memory, and the offset from which it is read is also stored. A strong collision-resistant cryptographic hash representation, such as a strong collision-resistant cryptographic hash, of the block is determined. The cryptographic hash representation (CHR) of the block of data as well as the data itself, is added to a table with the CHR as a unique index. The offset of the block of data in the source file, as well as the CHR for that block are appended to a separate table.

Abstract: A database rollback processor allows rollback, or rewind, of the data and metadata to a point at which a failover or other metadata change occurred, therefore “rewinding” the metadata to a previous consistent point. The rollback processor identifies transaction entries in a redo log resulting in changes to the metadata. The changes are identified backward to a target recovery time. Transactions affecting the metadata are stored in a stack. The transactions are then backed out of the metadata according to the stack to restore the metadata to the state at the target recovery time. Data changes from the redo log may then be applied to the corresponding metadata as it existed at the target recovery time. Since the target recovery time is not bound by the timing of the snapshots, but rather may be at an arbitrary point chosen as the target recovery time, a failover, replication or recovery operation need not rely on the snapshot time.

Abstract: According to some embodiments, a column-oriented in-memory database structure may be established. The database structure may, for example, include a main store and a dictionary compressed delta store. Moreover, the delta store may comprise a value identifier vector and a delta dictionary associated with a column of the database. A transaction associated with the column may then be received and recorded within the delta store. According to some embodiments, entries associated with the transaction may be added to a value log of the value identifier vector and, independently, to a dictionary log of the delta dictionary.

Abstract: A distributed system with transaction support may have a transaction component and one or more data components. The transaction component may manage a transaction using a log sequence number for each operation, and then transmit operations to one or more data components with log sequence numbers. The data components may perform the data operations in an idempotent manner and return a reply. The transaction component may then write the operation, its log sequence number, and information from the reply message to its log. The transaction component is able to commit a transaction, as well as retry or undo portions of a transaction, by using the information stored on its log. This may be possible even when a single transaction uses multiple data components, which may be located on different devices or manage separate and independent data sources.

Abstract: Methods and arrangements for prioritizing customer service restoration, in the event of service failure or compromise such that any adverse effect of the service disruption on the customer is minimized, the perceived drop in quality of service, if any, is minimized and timely and efficient resource reallocation for service restoration is achieved. Input data relating to customer service protocols is assimilated. A service restoration order is implemented responsive to a service disruption and based on the assimilated input data. This implementing includes determining bufferable and non-bufferable services, postponing restoration of the bufferable services, and determining an order of priority of the non-bufferable services.

Abstract: A bulk delete operation with reduced latency allows for retrieval of deleted data. Each database object holds a Delete SCN indicating when a bulk delete operation was last performed. Each row in the database object holds a Row Modification SCN indicating when the row was last updated. A bulk delete is performed by writing the old value of the Delete SCN to the undo tablespace and updating the Delete SCN. No undo information is stored for the rows. A write is performed by finding a deleted row, storing undo information for the deleted row and writing over the deleted row. To read from the database object, a rollback operation is performed, if necessary. Those rows are then retrieved for which the Row Modification SCN is higher than the Delete SCN and is less than or equal to the timestamp for the requested data.

Abstract: A novel and useful system and method of fast history compression in a pipelined architecture with both speculation and low-penalty misprediction recovery. The method of the present invention speculates that a current input byte does not continue an earlier string, but either starts a new string or represents a literal (no match). As previous bytes are checked if they start a string, the method of the present invention detects if speculation for the current byte is correct. If speculation is not correct, then various methods of recovery are employed, depending on the repeating string length.