Abstract: In an embodiment, before modifying a persistent ORL (ORL), a database management system (DBMS) persists redo for a transaction and acknowledges that the transaction is committed. Later, the redo is appended onto the ORL. The DBMS stores first redo for a first transaction into a first PRB and second redo for a second transaction into a second PRB. Later, both redo are appended onto an ORL. The DBMS stores redo of first transactions in volatile SRBs (SLBs) respectively of database sessions. That redo is stored in a volatile shared buffer that is shared by the database sessions. Redo of second transactions is stored in the volatile shared buffer, but not in the SLBs. During re-silvering and recovery, the DBMS retrieves redo from fast persistent storage and then appends the redo onto an ORL in slow persistent storage. After re-silvering, during recovery, the redo from the ORL is applied to a persistent database block.

Abstract: In an embodiment, before modifying a persistent ORL (ORL), a database management system (DBMS) persists redo for a transaction and acknowledges that the transaction is committed. Later, the redo is appended onto the ORL. The DBMS stores first redo for a first transaction into a first PRB and second redo for a second transaction into a second PRB. Later, both redo are appended onto an ORL. The DBMS stores redo of first transactions in volatile SRBs (SLBs) respectively of database sessions. That redo is stored in a volatile shared buffer that is shared by the database sessions. Redo of second transactions is stored in the volatile shared buffer, but not in the SLBs. During re-silvering and recovery, the DBMS retrieves redo from fast persistent storage and then appends the redo onto an ORL in slow persistent storage. After re-silvering, during recovery, the redo from the ORL is applied to a persistent database block.

Abstract: In an embodiment, before modifying a persistent ORL (ORL), a database management system (DBMS) persists redo for a transaction and acknowledges that the transaction is committed. Later, the redo is appended onto the ORL. The DBMS stores first redo for a first transaction into a first PRB and second redo for a second transaction into a second PRB. Later, both redo are appended onto an ORL. The DBMS stores redo of first transactions in volatile SRBs (SLBs) respectively of database sessions. That redo is stored in a volatile shared buffer that is shared by the database sessions. Redo of second transactions is stored in the volatile shared buffer, but not in the SLBs. During re-silvering and recovery, the DBMS retrieves redo from fast persistent storage and then appends the redo onto an ORL in slow persistent storage. After re-silvering, during recovery, the redo from the ORL is applied to a persistent database block.

Abstract: Techniques for processing changes in a cluster database system are provided. A first instance in the cluster transfers a data block to a second instance in the cluster before a redo record that stores one or more changes that the first instance made to the data block is durably stored. The first instance also transfers, to the second instance, a block change timestamp that indicates when a redo record for the one or more changes was generated by the first instance. The first instance also separately sends, to the second instance, a last store timestamp that indicates when the last redo record that was durably stored was generated by the first instance. The block change timestamp and the last store timestamp are used by the second instance when creating redo records for changes (made by the second instance) that depend on the redo record generated by the first instance.

Abstract: Techniques for processing changes in a cluster database system are provided. A first instance in the cluster transfers a data block to a second instance in the cluster before a redo record that stores one or more changes that the first instance made to the data block is durably stored. The first instance also transfers, to the second instance, a block change timestamp that indicates when a redo record for the one or more changes was generated by the first instance. The first instance also separately sends, to the second instance, a last store timestamp that indicates when the last redo record that was durably stored was generated by the first instance. The block change timestamp and the last store timestamp are used by the second instance when creating redo records for changes (made by the second instance) that depend on the redo record generated by the first instance.

Abstract: Techniques for moving data files without interrupting access are described. A first process moves a database file from a first location to a second location while the database file is accessible to one or more other processes for read or write operations. According to one technique, the first process communicates a move status and a copy range into the database file to one or more database server instances executing the one or more other processes. The one or more other processes then perform input/output (IO) operations on the database file based at least in part on the move status and the copy range communicated by the first process.

Abstract: A method and system is provided for reducing delay to applications connected to a database server that guarantees no data loss during failure or disaster. After storing a log record persistently in a local primary log, the log writer returns control to the application which continues running concurrently with the database server sending the session's log records to a standby database. A separate back channel is used by the standby to communicate, out-of-band to the primary, the location of the last log record stored persistently to the standby log. An application waiting for a transaction to commit may wait until the transaction's commit record has been persisted. Also described is a technique for reducing application delay when there is contention between nodes of a multi-node cluster for updating the same block. The technique provides for an asynchronous ping protocol that guarantees zero data loss during failure or disaster.

Abstract: Techniques for moving data files without interrupting access are described. A first process moves a database file from a first location to a second location while the database file is accessible to one or more other processes for read or write operations. According to one technique, the first process communicates a move status and a copy range into the database file to one or more database server instances executing the one or more other processes. The one or more other processes then perform input/output (IO) operations on the database file based at least in part on the move status and the copy range communicated by the first process.

Abstract: A method and system is provided for reducing delay to applications connected to a database server that guarantees no data loss during failure or disaster. After storing a log record persistently in a local primary log, the log writer returns control to the application which continues running concurrently with the database server sending the session's log records to a standby database. A separate back channel is used by the standby to communicate, out-of-band to the primary, the location of the last log record stored persistently to the standby log. An application waiting for a transaction to commit may wait until the transaction's commit record has been persisted. Also described is a technique for reducing application delay when there is contention between nodes of a multi-node cluster for updating the same block. The technique provides for an asynchronous ping protocol that guarantees zero data loss during failure or disaster.