Subject RE: [firebird-support] Deadlock error from firebird during midnight
Author Joje

Hi All,


In my case there is no large data to be analysed, only a timer that checks whether it is midnight or not. If it is midnight then update a single row in database this is done using stored procedure.


Confusing part is below error occurs only between midnight that is from 12 to 2 AM. During this time stored procedure executed will return deadlock error or timeout exception.


1.       “ERR::-2147467259: Deadlock concurrent transaction number is 5744401”

2.       ERR::Error reading data from the connection.; FirebirdSql.Data.FirebirdClient

3.       ERR::Timeout exceeded.; FirebirdSql.Data.FirebirdClient:  

ERR::-2146233079: Connection must be valid and open

   at FirebirdSql.Data.FirebirdClient.FbCommand.CheckCommand()

   at FirebirdSql.Data.FirebirdClient.FbCommand.ExecuteScalar()


I don’t think it has to do anything with FB as it this same stored procedures work fine during day time without any issues.


Thank you.

From: []
Sent: 03 December 2017 06:08 PM
Subject: Re: [firebird-support] Deadlock error from firebird during midnight





On Sun, Dec 3, 2017 at 5:04 PM, DougC doug@... [firebird-support] <> wrote:


Please, let us know what the cause ended up being and how you resolved the problem!


Alright, I will explain the issue in detail.

1. I have a .NET application of mine deployed since about last 7 yrs with about 90 tables in the firebird database.  Very routinely, as per customer’s requirement, I need to carry out changes to database structure [adding / renaming / removing – field(s) OR table(s)]. After doing such updates to my database structure I copy data to the new design database, through a .NET application.

2. Recently after about 7 yrs, I started to get exception “Error reading data from the connection” during transfer of data for a table which now had grown to about 13,26,000 records. For this table I was using FbDataAdapter to copy data in batches of 50,000 records.

3. I observed that every time the exception was raised after copying 12,50,000. So from the source, I deleted the already copied 12,50,000 records and resumed to copy the remaining 76,000. This too failed.

4. Later all my attempts as under failed:

(a) using FbDataReader in place of FbDataAdapter.

(b) changing connecting string elements like Connection Timeout, Connection lifetime, Pooling.

(c) Copying after backup-restore of both source and destination database.

(d) Changing machines.


5.  So I wrote a stored procedure with inputs from Dimitry which copied records using execute Statement On External database. This stored procedure I executed through FbCommand's ExecuteNonQuery. This worked fine.

6. Now on Dimitry’s advice I changed the FbTransaction from:


FbTransaction tx = con.BeginTransaction();




FbTransaction tx = con.BeginTransaction(

new FbTransactionOptions() {TransactionBehavior =

FbTransactionBehavior.Concurrency |



And found that FbDataAdapter also started to work correct.


7. The option at Para 5 is much faster. In case you need more details / code I will please share.




---- On Sat, 02 Dec 2017 23:08:49 -0500 LtColRDSChauhan rdsc1964@... [firebird-support] <> wrote ----


  Thanks a lot, Dimitry !

This issue of mine, for which I had posted for help on the firebird-net-provider group, is now resolved.