Question

I’ve tried to insert BLOB data with SQL developer. But I can’t find the insert statements which are actually used to insert BLOB data.

Apart from that, the database speed is really slow. For small files, it executes fine. But when I tried to import 50 mb avi file into BLOB, it took 3-4 minutes & still it was not completed. When I tried to export the BLOB data to a file, exporting process was also slow. I was using Oracle 10g Express Edition. If the database speed is slower than even file-system speed, then why database are used for storing BLOB data? Is there any other way to optimize the performance?

Answer 1

First of all, you should expect storing BLOBs in a database to be (sometimes a bit, often significantly) slower, but definitly not faster than storing them in a file system. The reasons to store them in a DB do not center about performance, but about e.g.:

• Unavailability of a (shared) file system in a clustered or load-balanced scenario
• Ease of backup: Single process, a.o.t. 2 processes when files and DB are used
• Transaction safety: A BLOB is either there and complete or not, but not in a half-baked stage
• others I can’t think of right now.

The general rule of thumb is, that if none of these concern you, you should store your files as … files. Storing the metadata and pathname in a DB is IMHO good and common practice.

Concerning Oracle tuning: There are books written about that. I suspect to total them far over a ton in dead-tree-paperback format. You might first of all look at the Oracle process’ memory consumption – rule of thumb: If it is less than a gig and you use BLOBs, you are in trouble. Read up on the different memory pools and how to increase them. Some limits for the express edition might apply.