Re: using lobs system types to manually clear data
Fred Toussi <[email protected]>
| Newsgroups | gmane.comp.java.hsqldb.user |
|---|---|
| Message-ID | <[email protected]> |
It is easier to delete the rows that contain the lobs. The spaces then become available for new lobs after a checkpoint. Create a a table with a lob column and insert random data in multiples of 32 GB. This will fill up the space. Then delete rows from this table and finally perform a checkpoint to release the space again. The LOB_IDS table is for the currently existing lobs that have a reference, not deleted ones. Fred On Wed, May 21, 2014, at 18:38, Brian Young wrote: Hello, in our usage of hsqldb, it is sometimes necessary to permanently delete blobs such that someone "in the know" couldn't recover said blob from the .lobs file. I am considering reading the system tables and zero out the blocks that are identified as having no active references. Obviously this would be done while the database is "offline", meaning the cleanup process is the owner and single user of the database. I am assuming LOB_IDS.LOB_LENGTH is in bytes, but how do I determine the offset a given LOB within the .lobs file? Are there any gotchas here? Thanks ----------------------------------------------------------------------- ------- "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." [1]http://p.sf.net/sfu/SauceLabs _______________________________________________ Hsqldb-user mailing list [2][email protected] [3]https://lists.sourceforge.net/lists/listinfo/hsqldb-user References 1. http://p.sf.net/sfu/SauceLabs 2. mailto:[email protected] 3. https://lists.sourceforge.net/lists/listinfo/hsqldb-user ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Hsqldb-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/hsqldb-user