Quantifying complexity of a database application

1. A method for quantifying workload placed on a first database by an application, the method comprising:

identifying a first plurality of database queries that the application directed towards the first database;

producing a second plurality of queries by removing, from the first plurality, queries that are duplicates based on semantic structure of the queries;

based on a set of properties of the second plurality of queries, computing a complexity indicator that represents a level of difficulty for rewriting the second plurality of queries for a second database that is a candidate database for migrating data in the first database; and

presenting the complexity indicator in a display to allow a user to determine whether the data should be migrated from the first database to the second database.

2. The method of claim 1 , wherein removing the duplicate queries comprises:

identifying a group of one or more duplicate sets of queries, each duplicate set comprising two or more queries that have the same query structure; and

eliminating, from the first plurality, all but one of each query in each identified duplicate query set.

3. The method of claim 1 , wherein removing the duplicate queries comprises:

for each identified query in the first plurality of queries, generating a query identifier based on a set of components of the identified query;

using the query identifiers to identify duplicate queries in the first plurality of queries.

4. The method of claim 1 , wherein the complexity indicator further represents a level of difficulty for verifying the results of executing the second plurality of queries on the second database.

5. The method of claim 1 , wherein each query in the second plurality is a unique query that does not have a same set of components as another query in the second plurality.

6. The method of claim 3 , wherein the query identifiers are hash values.

7. The method of claim 3 , wherein generating a query identifier for a query comprises generating a hash value from the set of components of the query.

8. The method of claim 1 , wherein the complexity indicator informs a user decision to migrate the application to a second database.

9. The method of claim 1 , wherein the first database is of a first database type, wherein the second database is of a second, different database type.

10. The method of claim 8 , wherein presenting the complexity indicator comprises generating a report comprising the complexity indicator for display on a user interface, wherein the report informs the user's determination.

11. The method of claim 10 , wherein the report comprises a plurality of complexity indicators for a plurality of applications that also direct queries to the first database.

12. A non-transitory machine readable medium storing a program which when executed by at least one processing unit quantifies a workload placed on a first database by an application, the program comprising sets of instructions for:

identifying a first plurality of database queries that the application directed towards the first database;

producing a second plurality of queries by removing, from the first plurality, queries that are duplicates based on semantic structure of the queries;

based on a set of properties of the second plurality of queries, computing a complexity indicator that represents a level of difficulty for rewriting the second plurality of queries for a second database that is a candidate database for migrating data in the first database; and

presenting the complexity indicator in a display to allow a user to determine whether the data should be migrated from the first database to the second database.

13. The non-transitory machine readable medium of claim 12 , wherein the set of instructions for removing the duplicate queries comprises sets of instructions for:

identifying a group of one or more duplicate sets of queries, each duplicate set comprising two or more queries that have the same query structure; and

eliminating, from the first plurality, all but one of each query in each identified duplicate query set.

14. The non-transitory machine readable medium of claim 12 , wherein the set of instructions for removing the duplicate queries comprises sets of instructions for:

for each identified query in the first plurality of queries, generating a query identifier based on a set of components of the identified query;

using the query identifiers to identify duplicate queries in the first plurality of queries.

15. The non-transitory machine readable medium of claim 12 , wherein the complexity indicator further represents a level of difficulty for verifying the results of executing the second plurality of queries on the second database.

16. The non-transitory machine readable medium of claim 12 , wherein each query in the second plurality is a unique query that does not have a same set of components as another query in the second plurality.

17. The non-transitory machine readable medium of claim 14 , wherein the query identifiers are hash values.

18. The non-transitory machine readable medium of claim 14 , wherein the set of instructions for generating a query identifier for a query comprises a set of instructions for generating a hash value from the set of components of the query.

19. The non-transitory machine readable medium of claim 12 , wherein a user interface informs a user decision to migrate the set of applications to a second database.

20. The non-transitory machine readable medium of claim 19 , the set of instructions for presenting the complexity indicator comprises a set of instructions for generating a report comprising the complexity indicator for display on the user interface, wherein the report (i) comprises a plurality of complexity indicators for a plurality of applications that also direct queries to the first database and (ii) informs the user's determination.