Bi-directional data sync between a client device and an application server

A system for performing data synchronization in a client device executing a mobile application and being in communication with an application server over a network connection having unreliable network connectivity, the system comprising:

• a hardware processor;
• and
• a memory coupled with the hardware processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:
• exchange data with the application server where the data comprises data objects stored in a central database in communication with the application server, the application server assigning a first group of data objects stored in the central database to no data bucket and assigning a second group of data objects stored in the central database to one or more data buckets, and the application server further designating one or more data buckets to the client device, the data buckets designated to the client device including a subset of the data objects stored in the central database;
• store in a first table at the client device data associated with the one or more data buckets designated to the client device;
• execute the mobile application using the data in the first table;
• in response to the network connection not being established between the client device and the application server, store in a second table at the client device changes to the data in the first table as a result of the executing;
• and
• in response to the network connection being established between the client device and the application server, perform synchronization of data with the application server, the synchronization comprising:
• upload data stored in the second table to the application server to synchronize data objects in the central database associated with the one or more data buckets designated to the client device;
• receive download data from the application server for new or modified data objects associated with the one or more data buckets designated to the client device;
• receive from the application server a list of data buckets designated to the client device;
• in response to a change in the data buckets designated to the client device, synchronize with the application server data in the first table associated with the change in the data buckets, the first table storing data associated with all of the data buckets designated to the client device;
• perform an integrity check of the data stored in the first table;
• in response to detecting a mismatch of the data, determine the range of data having the mismatch;
• in response to the mismatched data being within a small range, download the data from the application server;
• and
• in response to the mismatched data being within a large range, divide the mismatched data into smaller ranges and repeat performing the integrity check on the divided range of data.

A method in an application server hosting backend application services of a mobile application being executed on a remote client device, the application server being in communication the remote client devices over a network connection having unreliable network connectivity, the method comprising:

• storing data objects associated with the execution of the mobile application by the remote client device in a central database;
• storing in a third table one or more synchronization rules assigning a first group of data objects stored in the central database to no data bucket and assigning a second group of data objects stored in the central database to one or more data buckets;
• storing in the third table one or more synchronization rules designating one or more data buckets to the remote client device;
• storing in a fourth table one or more ordered entries associated with data objects that have been modified;
• in response to the network connection being established between the remote client device and the application server, performing, using a processor, synchronization of data with the remote client device, the synchronization comprising:
• downloading to the remote client device modified data objects associated with data buckets designated to the remote client device, the modified data objects being identified in the fourth table;
• receiving uploaded data from the remote client device, the uploaded data being associated with the data buckets designated to the remote client device;
• downloading a list of data buckets designated to the remote client device in response to the one or more synchronization rules stored in the third table;
• in response to a request for an integrity check received from the remote client device for data stored on the remote client device, selecting a first range of sequence ID corresponding to a range of sequence ID of the data stored on the remote client device and determining if there is a mismatch of the data stored on the remote client device and the data stored on the application server;
• in response to detecting a mismatch of the data, determining the range of data having the mismatch;
• in response to the mismatched data being within a small range, downloading the data from the application server to the remote client device;
• and
• in response to the mismatched data being within a large range, dividing the mismatched data into smaller ranges and repeat performing the integrity check on the divided range of data.