BLOB not found in SuperClassic and Classic on Uncommitted Transactions
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Key: CORE-4678
URL: http://tracker.firebirdsql.org/browse/CORE-4678
Project: Firebird Core
Issue Type: Bug
Affects Versions: 2.5.3 Update 1
Environment: Windows Server 2008/2012 and Windows 7
Firebird: 2.5.3.26778 and 2.5.2.26540
Reporter: Israel Lopez
I'm supporting a commercial product that happens to use Firebird SQL. As part
of new vendor updates, the Firebird installation was upgraded from 2.5.2.26540
to 2.5.3.26778.
The customer who uses the commercial product uses a feature in the database
schema known as a "memo" which is stored as a BLOB datatype. Specifically: BLOB
SUB_TYPE 1 SEGMENT SIZE 100 CHARACTER SET ASCII
The users started reporting errors in the application, which upon inspection
was a Stacktrace message through JayBird, through Hibernate, and through the
application code. They were receiving the following error message "BLOB not
found." Because no other changes were made, and no other customers reported
the issue on the same new version, we had believed it was hardware. While
waiting for the hardware specialists to respond I created a test application to
confirm.
The test code is hosted here: https://github.com/ilopez/Firebird.TestBlobs
Binaries are available here:
https://github.com/ilopez/Firebird.TestBlobs/releases/download/0.1/Debug.zip
Arguments are TestFirebirdBlobs.exe [1] [2] [3]
1 - Path to DB
2 - Username
3 - Password
The application drops the DB, and creates a new DB, then applies the selected
schema I was testing.
For testing; two connections are created, one for inserting, and another for
selecting. For the first connection, I insert records, but do not commit and
close the connection. Then I create a new second connection and do a simple
count on the table. Using this code, and switching the MEMO type field from
VARCHAR(256) to the BLOB type, I can confirm and replicate the results the
users were seeing.
On SuperClassic and Classic for 2.5.3.26778 I receive a BLOB not found when
using the second connection, on 2.5.2.26540 I receive no errors for both
VARCHAR and BLOB types.
Command Example output and testing results:
https://gist.github.com/ilopez/7d36e860a7a31373cca9
It appears there has been some kind of regression that exposes the first
connection's inserts, to the second connections reads, and therefore we receive
BLOB not found errors. Writing this separate code, confirms that it was not
the commercial software's code OR the customer's hardware causing this issue.
My workaround is going to be to revert back to 2.5.2.26540.
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