Re: Disappearing BLOB space

Jonathan Leffler writes: |> |> }From: Dave Snyder <uunet!snide.com!dave.snyder> |> }Subject: Disappearing BLOB space |> }Date: Wed, 24 Mar 1993 18:46:27 -0500 (EST) |> }X-Informix-List-Id: <list.2047> |> |> } We have a rootdbs and also a blob-space (for TEXT blobs) |> } When we delete a row from the table which has a blob, why isn't that |> } deletion reflected in the free-page count for the blob-space? |> } Also, if we right-of-way add a new row to the table and include a blob, |> } the free-page count immediately reflects the addition of the blob. |> |> }At first I thought that this was something similar to the way deleted rows |> }in Informix-SE don't reduce the size of the data file. But when you add |> }a new row in SE, the size of the data file doesn't grow until you fill up |> }all the holes left by deleted rows. This doesn't seem to be the case in |> }ONLINE's blob-space. Any ideas? |> |> Have you backed up the logical logs between the time when you released the |> data and the time when you check on the free space. If you read the small |> print on blob handling, you will find that the blob space is not available |> for re-use until the blob cannot be required for recovery, because OnLine |> does not put blob data from blob spaces into the logical log. Page 2-141 |> of the 5.00 OnLine Admins Guide is relevant. Jonathan is correct as far as he goes, but you really need to take it a step further: the space is not released until the log containing the transaction that changed the blob (update, delete) is FREED. Thus, even backing the log up is not sufficient (since a backed up log will not necessarily be freed at backup time). Dave