Serving a network resource usage file

1. A method of serving a network resource usage record file, the method comprising:

storing network resource usage records in a database, the network resource usage records relating to network resource usage in a telecommunications network;

estimating a file size for a network resource usage record file without having constructed the network resource usage record file by obtaining, from the database, metadata indicating a size of the one or more network resource usage records;

sending a file list identifying the network resource usage record file over a file retrieval interface without having constructed the network resource usage record file;

receiving, over the file retrieval interface, a request for the network resource usage record file;

constructing, in response to the receiving of the request, the network resource usage record file, the network resource usage record file comprising one or more network resource usage records obtained from the database; and

serving, over the file retrieval interface, the network resource usage record file.

2. A method according to claim 1 , wherein said constructing comprises generating a header for the network resource usage record file based on the one or more network resource usage records, wherein the network resource usage record file comprises the header.

3. A method according to claim 2 , wherein the header indicates the number of network resource usage records comprised in the network resource usage record file.

4. A method according to claim 2 , wherein the header indicates a file size of the network resource usage record file.

5. A method according to claim 1 , comprising generating a filename for the network resource usage record file without having constructed the network resource usage record file.

6. A method according to claim 5 , wherein the file list and/or the received request identifies the filename for the network resource usage record file.

7. A method according to claim 5 , comprising obtaining the one or more network resource usage records from the database using at least part of the filename for the network resource usage record file.

8. A method according to claim 5 , wherein the network resource usage record file is indicative of network resource usage in the telecommunications network during a given time period and wherein the filename identifies at least part of the given time period.

9. A method according to claim 8 , wherein the filename identifies a start time and/or an end time of the given time period.

10. A method according to claim 1 , wherein the file size information indicates that the network resource usage record file has a file size of zero.

11. A method according to claim 1 , wherein the method is performed by a data processing node in a cluster of data processing nodes and wherein the data processing node and at least one other data processing node in the cluster of data processing nodes have access to the database.

12. A method according to claim 1 , wherein the file retrieval interface uses FTP, FTPS, SFTP or SCP.

13. A method according to claim 1 , wherein the file list is sent in response to receiving, over the file retrieval interface, a file list request or a directory listing request.

14. A method according to claim 1 , wherein the database is a distributed database.

15. A data processing node comprising non-transitory data storage storing computer-readable instructions that, when executed by one or more processors of the data processing node, cause the data processing node to perform operations comprising:

storing network resource usage records in a database, the network resource usage records relating to network resource usage in a telecommunications network;

estimating a file size for a network resource usage record file without having constructed the network resource usage record file by obtaining, from the database, metadata indicating a size of the one or more network resource usage records;

sending a file list identifying the network resource usage record file over a file retrieval interface without having constructed the network resource usage record file;

receiving, over the file retrieval interface, a request for the network resource usage record file;

constructing, in response to the receiving of the request, the network resource usage record file, the network resource usage record file comprising one or more network resource usage records obtained from the database; and

serving, over the file retrieval interface, the network resource usage record file.

16. A non-transitory data storage storing computer-readable instructions that, when executed by one or more processors, cause performance of operations comprising:

storing network resource usage records in a database, the network resource usage records relating to network resource usage in a telecommunications network;

estimating a file size for a network resource usage record file without having constructed the network resource usage record file by obtaining, from the database, metadata indicating a size of the one or more network resource usage records;

sending a file list identifying the network resource usage record file over a file retrieval interface without having constructed the network resource usage record file;

receiving, over the file retrieval interface, a request for the network resource usage record file;

constructing, in response to the receiving of the request, the network resource usage record file, the network resource usage record file comprising one or more network resource usage records obtained from the database; and

serving, over the file retrieval interface, the network resource usage record file.