Data recovery in a distributed system
First Claim
1. A method for recovering data in a distributed system where the data is maintained in at least two databases, one of the databases being a master database and at least one other database being a slave database, and the data comprises at least one data element, the method comprising:
- initiating recovery of the data;
calculating during the recovery a first total from the data in a first database and a second total from a corresponding data in a second database;
comparing the first total with the second total;
if the first total and the second total are the same, ending the recovery of the data;
if the first total and the second total are not the same, the method further comprises during the recovery;
a) dividing the data and the corresponding data into at least two smaller data groups according to a predetermined rule;
b) calculating a third total for each data group in the first database and a fourth total for each corresponding data group in the second database;
c) comparing for each data group the third total with the fourth total; and
d) deducing on the basis of this comparison in which data group or data groups updating is needed.
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Accused Products
Abstract
In a distributed system, where data is maintained in at least two databases and the data includes at least one data element, the amount of data transmitted during data recovery is minimized by comparing a first total of the data elements of the data in a first database with a second total of a corresponding data elements of corresponding data in a second database. An updating procedure for the data element is initiated if the first total and the second total are not the same.
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Citations
20 Claims
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1. A method for recovering data in a distributed system where the data is maintained in at least two databases, one of the databases being a master database and at least one other database being a slave database, and the data comprises at least one data element, the method comprising:
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initiating recovery of the data; calculating during the recovery a first total from the data in a first database and a second total from a corresponding data in a second database; comparing the first total with the second total; if the first total and the second total are the same, ending the recovery of the data; if the first total and the second total are not the same, the method further comprises during the recovery; a) dividing the data and the corresponding data into at least two smaller data groups according to a predetermined rule; b) calculating a third total for each data group in the first database and a fourth total for each corresponding data group in the second database; c) comparing for each data group the third total with the fourth total; and d) deducing on the basis of this comparison in which data group or data groups updating is needed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system comprising at least two network nodes, each of which comprises a memory having at least first data, the first data comprising at least one data element, the network nodes being arranged to maintain the first data;
the system being arranged to initiate recovery of the first data;
to calculate, during the recovery of the first data, a first total from the data in a first memory of a first network node and a second total from the corresponding data in a second memory of a second network node;
to compare the first total with the second total; and
if the first total and second total are not the same;
to divide the first data and the corresponding data into at least two smaller data groups according to a predetermined rule;
to calculate a third total for each data group in the first memory and a fourth total for each corresponding data group in the second memory;
to compare for each data group the third total with the fourth total; and
to deduce on the basis of this comparison in which data group or data groups updating is needed.- View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A network node comprising a memory having at least first data, the first data comprising at least one data element;
- the network node being arranged to maintain the first data and to be in connection with a second network node comprising second data corresponding to the first data;
wherein the network node is arranged, in response to receiving a second total of the second data during recovery of the first data, to calculate a first total from the first data;
to compare the second total with the first total; and
to request for third totals if the first total and the second total are not the same; and
, in response to receiving third totals, to divide the first data into at least two smaller data groups according to a predetermined rule;
to calculate a fourth total for each data group;
to compare each fourth total with a corresponding third total; and
to deduce on the basis of this comparison in which data group or data groups updating is needed.
- the network node being arranged to maintain the first data and to be in connection with a second network node comprising second data corresponding to the first data;
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20. A network node in a system where at least first data is maintained in two network nodes;
- the network node comprising a memory having at least the first data, the first data comprising at least one data element;
wherein the network node is arranged to maintain the first data and to be in connection with a second network node;
to calculate during recovery of the first data a first total from the first data;
to send the first total to the second network node;
to receive a response from the second network node; and
if the response indicates that further total is required to divide the first data into at least two smaller data groups according to a predetermined rule;
to calculate for each data group a third total; and
send the third totals to the second network node.
- the network node comprising a memory having at least the first data, the first data comprising at least one data element;
Specification