Migrating data in tables in a database

A computer program product encoded on a non-transitory storage medium, the product comprising non-transitory, computer readable instructions for causing one or more processors to perform operations comprising:

• identifying a first update to one or more data entries of a source table;
• in response to identifying the first update, determining that a status of a trigger associated with the source table indicates to update a logging table, and in response:
• updating, in a first transaction and based on the first update, (i) the one or more data entries of the source table, and (ii) one or more data entries of the logging table, and
• copying content of the source table to a target table;
• identifying a second update to one or more data entries of the source table;
• in response to identifying the second update, determining that the status of the trigger associated with the source table indicates to update the target table, and in response:
• updating, in a second transaction and based on the second update, (i) the one or more data entries of the source table and (ii) one or more data entries of the target table,
• updating the content of the target table based on the one or more data entries of the logging table, and
• determining that the source table and the target table are in-sync based on the updates to the target table;
• identifying a third update to one or more data entries of the source table;
• and
• in response to identifying the third update and based on determining that the source table and the target table are in-sync, updating, in a third transaction and based on the third update, one or more data entries of the target table,
• wherein the first transaction and the second transaction occur in parallel, and copying the content of the source table to the target table includes excluding one or more data entries from the source table to the target table that are being transferred during the second transaction.

A system of one or more computers configured to perform operations comprising:

• identifying a first update to one or more data entries of a source table;
• in response to identifying the first update, determining that a status of a trigger associated with the source table indicates to update a logging table, and in response:
• updating, in a first transaction and based on the first update, (i) the one or more data entries of the source table, and (ii) one or more data entries of the logging table, and
• copying content of the source table to a target table;
• identifying a second update to one or more data entries of the source table;
• in response to identifying the second update, determining that the status of the trigger associated with the source table indicates to update the target table, and in response:
• updating, in a second transaction and based on the second update, (i) the one or more data entries of the source table and (ii) one or more data entries of the target table,
• updating the content of the target table based on the one or more data entries of the logging table, and
• determining that the source table and the target table are in-sync based on the updates to the target table;
• identifying a third update to one or more data entries of the source table;
• and
• in response to identifying the third update and based on determining that the source table and the target table are in-sync, updating, in a third transaction and based on the third update, one or more data entries of the target table,
• wherein the first transaction and the second transaction occur in parallel, and copying the content of the source table to the target table includes excluding one or more data entries from the source table to the target table that are being transferred during the second transaction.