Determining and extracting changed data from a data source

A method of obtaining changed data from a data source, the method comprising:

• obtaining, by one or more hardware computer processors, information indicating a plurality of groupings of data of a data source, the information indicating a number of data items included in each of the plurality of groupings;
• determining, by the one or more hardware computer processors, a first grouping of the plurality of groupings including one or more data items that have changed by comparing a first number of data items included in the first grouping and a historical number of data items included in each of the plurality of groupings;
• accessing, by the one or more hardware computer processors, data items included in the first grouping from the data source;
• comparing, by the one or more hardware computer processors, the data items included in the first grouping to data items of a corresponding local version of the first grouping to determine which data items of the first grouping from the data source have changed, wherein the corresponding local version of the first grouping of data items is a compressed version of the first grouping of data items;
• extracting, by the one or more hardware computer processors, the changed data items of the first grouping;
• and
• forwarding, by the one or more hardware computer processors, the extracted changed data items to a destination system.

A non-transitory computer readable storage medium comprising instructions for obtaining changed data from a data source that cause a computer processor to:

• obtain information indicating a plurality of groupings of data of a data source, the information indicating a number of data items included in each of the plurality of groupings;
• determine a first grouping of the plurality of groupings including one or more data items that have changed by comparing a first number of data items included in the first grouping and a historical number of data items included in each of the plurality of groupings;
• access data items included in the first grouping from the data source;
• compare the data items included in the first grouping to data items of a corresponding local version of the first grouping to determine which data items of the first grouping from the data source have changed, wherein the corresponding local version of the first grouping of data items is a compressed version of the first grouping of data items,
• wherein the compressed version of the first grouping of data items is a space-efficient probabilistic data structure including information about data items included in the first grouping at a first time prior to said obtaining the information indicating the plurality of groupings of the data of the data source, and wherein the space-efficient probabilistic data structure is configured to determine whether a particular data item included in the first grouping was included in the first grouping at the first time;
• extract the changed data items of the first grouping;
• and
• transmit the extracted changed data items to a destination system.