Subject Re: [firebird-support] Re: Truncating transaction logs in Firebird in v2.01 - v2.03
Author Niben M Singh
Thanks for the responses!

I guess in Firebird term it is called SWEEP or GARBAGE COLLECTION.
GBAK does garbage collection by default, unless you specify "-g" option.

So it is confusing to me when I backed up the database after manual SWEEPING and with Garbage Collection -- Restored the database from backup into new file -- SWEEPED new database again -- again backed it up with garbage collection -- and eventually re-restored again into new database file.

After doing that the final size of the new file is dramatically reduced. The data and schema has not changed, however....


Helen Borrie <helebor@...> wrote: At 11:55 AM 14/04/2008, Adam wrote:
>--- In, Niben M Singh <niben_s@...>
>> Hello All -
>> I have tried this on Firebird Database v2.01 and v2.03.
>> I created new Firebird database with page size 4KB and transferred
>data using ODBC. This database has about 400 tables and about 500MB
>size right now. After I created the database I thought about
>truncating transaction logs.
>What are these 'transaction logs' you are talking about? Are they
>tables within your database, or something you think Firebird has?

InterBase 2007 implemented some kind of journalling...which Firebird doesn't do. Maybe he's confused by that. Or maybe he's confusing Firebird with Codegear's Blackfish ? (used to be jDataStore?) That has some "log truncation" facility....

Or maybe he's talking about the isc_tpb_no_auto_undo parameter that can be optionally specified (via an API call only, not SQL) to disable savepoint "framing" for a transaction, typically where you're running a big batch insert or update. But the savepoint log is a memory structure, not stored in a database, and it disappears once the transaction is committed or rolled back. It's an "all-or-nothing" facility that is enabled by default and may be abandoned by the server, anyway, if memory gets too scarce. No "truncation".


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