Synchronization of a disaster-recovery system
A method and associated systems for synchronizing a disaster-recovery system of a database. A processor identifies transactions that affect data blocks of a database and records each change in a vector form. For each block, the processor determines a more efficient way to communicate changes made to the block by a subset of the identified transactions. If fewer resources are needed to communicate an updated image of the entire changed block than would be needed to instead communicate a related set of change vectors that identify changes made to the block by the subset of transactions, then the processor communicates the updated image to the disaster-recovery system. Otherwise, the processor instead communicates the related change vectors to the disaster-recovery system. The processor repeats these determinations and communications for each block of the database that was changed by an identified transaction.
1. A method for synchronizing a disaster-recovery system of a database, the method comprising:
monitoring a set of transactions associated with the database, where the database comprises a set of data blocks, and where each transaction of the set of transactions identifies an alteration to one or more data blocks of the set of data blocks;
choosing a subset of transactions of the set of transactions, where each transaction of the subset of transactions identifies an alteration to a first data block of the set of data blocks;
creating a set of block images, where a first image of the set of block images corresponds to the first data block;
generating a set of change vectors,
where each vector of the set of change vectors corresponds to one transaction of the subset of transactions
updating the first block image as a function of changes made to the first block image by the subset of transactions; and
determining whether transmitting the updated first block image to the disaster-recovery system is more efficient than transmitting the set of change vectors to the disaster-recovery system, where the determining is a function of comparing a first quantity of data comprised by the updated firm block image to a second quantity of data comprised by the set of change vectors.
2. The method of claim 1 , further comprising:
the processor transmitting either the first block image or the set of change vectors to the disaster-recovery entity as a function of the determining.
3. The method of claim 1 , where a first change vector of the set of change vectors corresponds to a first transaction of the subset of transactions, and where the first change vector comprises a block identifier that identifies the first data block and a change identifier that identifies the first transaction.
4. The method of claim 1 , where the choosing a subset comprises discarding an undo/redo transaction.
5. The method of claim 1 , where the choosing a subset comprises discarding a transaction that was not completed.
6. The method of claim 1 , where the choosing a subset comprises discarding a plurality of transactions that do not together effect a net change to data comprised by the first data block.
7. The method of claim 1 , where the transmitting is performed only if the updating results in a net change to data comprised by the first data block.
8. The method of claim 1 , where the determining is a further function of comparing a first quantity of data, which must be communicated in order to transmit the updated first block image to the disaster-recovery system, to a second quantity of data, which must be communicated in order to transmit the set of change vectors to the disaster-recovery system.
9. The method of claim 1 , further comprising providing at least one support service for at least one of creating, integrating, hosting, maintaining, and deploying computer-readable program code in the computer system, where the computer-readable program code in combination with the computer system is configured to implement the monitor, choosing, creating, generating, updating, and determining.
10. A computer program product, comprising a computer-readable hardware storage device having a computer-readable program code stored therein, said program code configured to be executed by a processor of a computer system to implement a method for synchronizing a disaster-recovery system of a database, the method comprising:
the processor monitoring a set of transactions associated with the database, where the database comprises a set of data blocks, and where each transaction of the set of transactions identifies an alteration to one or more data blocks of the set of data blocks;
the processor choosing a subset of transactions of the set of transactions, where each transaction of the subset of transactions identifies an alteration to a first data block of the set of data blocks;
the processor creating a set of block images, where a first image of the set of block images corresponds to the first data block;
the processor generating a set of change vectors,
where each vector of the set of change vectors corresponds to one transaction of the subset of transactions,
the processor updating the first block image as a function of changes made to the first block image by the subset of transactions; and
the processor determining whether transmitting the updated first block image to the disaster-recovery system is more efficient than transmitting the set of change vectors to the disaster-recovery system, where the determining is a function of comparing a first quantity of data comprised by the updated first block image to a second quantity of data comprised by the set of change vectors.
11. The computer program product of claim 10 , further comprising:
the processor transmitting either the first block image or the set of change vectors to the disaster-recovery entity as a function of the determining.
12. The computer program product of claim 10 , where a first change vector of the set of change vectors corresponds to a first transaction of the subset of transactions, and where the first change vector comprises a block identifier that identifies the first data block and a change identifier that identifies the first transaction.
13. The computer program product of claim 10 , where the choosing a subset comprises discarding an undo/redo transaction.
14. The computer program product of claim 10 , where the choosing a subset comprises discarding a transaction that was not completed.
15. The computer program product of claim 10 , where the determining is a further function of comparing a first quantity of data, which must be communicated in order to transmit the updated first block image to the disaster-recovery system, to a second quantity of data, which must be communicated in order to transmit the set of change vectors to the disaster-recovery system.
16. A computer system comprising a processor, a memory coupled to said processor, and a computer-readable hardware storage device coupled to said processor, said storage device containing program code configured to be run by said processor via the memory to implement a method for synchronizing a disaster-recovery system of a database, the method comprising:
the processor monitoring a set of transactions associated with the database, where the database comprises a set of data blocks, and where each transaction of the set of transactions identifies an alteration to one or more data blocks of the set of data blocks;
the processor choosing a subset of transactions of the set of transactions, where each transaction of the subset of transactions identifies an alteration to a first data block of the set of data blocks;
the processor creating a set of block images, where a first image of the set of block images corresponds to the first data block;
the processor generating a set of change vectors,
where each vector of the set of change vectors corresponds to one transaction of the subset of transactions;
the processor updating the first block image as a function of changes made to the first block image by the subset of transactions; and
the processor determining whether transmitting the updated first block image to the disaster-recovery system is more efficient than transmitting the set of change vectors to the disaster-recovery system, where the determining is a function of comparing a first quantity of data comprised by the updated first block image to a second quantity of data comprised by the set of change vectors.
17. The computer system of claim 16 , further comprising:
the processor transmitting either the first block image or the set of change vectors to the disaster-recovery entity as a function of the determining.
18. The computer system of claim 16 , where a first change vector of the set of change vectors corresponds to a first transaction of the subset of transactions, and where the first change vector comprises a block identifier that identifies the first data block and a change identifier that identifies the first transaction.
19. The computer system of claim 16 , where the choosing a subset comprises discarding an undo/redo transaction, discarding a transaction that was not completed, or discarding a plurality of transactions that do not together effect a net change to data comprised by the first data block.
20. The computer system of claim 16 , where the determining is a function of comparing a first quantity of data, which must be communicated in order to transmit the updated first block image to the disaster-recovery system, to a second quantity of data, which must be communicated in order to transmit the set of change vectors to the disaster-recovery system.