Database is in use - Cannot connect to the database with my application

Question

I am using Firebird 4.0 with SuperServer installed on Microsoft Windows 2011. I am developing a win64 database application with Delphi to access the database file on a remote computer.

If I connect to the database file with IBExpert while I also try to connect to the same database with the application I am developing, I get the following error message:

[FireDAC][Phys][FB]lock time-out on wait transaction
object D:\MYFILES\DATABASE\SZERYNG\IMOVEIS_FIREBIRD\BANCO DE DADOS\DBIMOVEIS.FDB is in use

I can open more than one IBExpert and connect to the same database file but I cannot connect to the database file with my application if any other application like IBExpert is connected to the same database file.

IBExpert FDConnection	IBExpert database registration info	My application's FDConnection parameters
Database Database File	D:\MyFiles\Database\Szeryng\Imoveis_Firebird\Banco de Dados\DBIMOVEIS.FDB	D:\MyFiles\Database\Szeryng\Imoveis_Firebird\Banco de Dados\DBIMOVEIS.FDB
Server/Protocol Protocol	Remote, TCP/IP	TCPIP
Server Name Server	127.0.0.1	127.0.0.1
Port	3040	3040
User Name User_Name	SYSDBA	SYSDBA
Charset Character Set	ISO8859_1	ISO8859_1
Server Version	Firebird 4.0
SQL Dialect		3
Client Library File FDPhysFBDriveLink.VendorLib	c:\windows\syswow64\fbclient.dll	c:\windows\system32\fbclient.dll

IBExpert database registration info:

Database File: D:\MyFiles\Database\Szeryng\Imoveis_Firebird\Banco de Dados\DBIMOVEIS.FDB
Server/Protocol: Remote, TCP/IP
Server Name: 127.0.0.1
Port: 3040
User Name: SYSDBA
Charset: ISO8859_1
Server Version: Firebird 4.0
Client Library File: c:\windows\syswow64\fbclient.dll

My application's FDConnection parameters:

Database: D:\MyFiles\Database\Szeryng\Imoveis_Firebird\Banco de Dados\DBIMOVEIS.FDB;
Protocol: TCPIP;
Server: 127.0.0.1;
Port: 3040;
User_Name: SYSDBA;
Character Set: ISO8859_1;
SQL Dialect: 3;
IBAdvanced: set_db_readonly=0;

FDPhysFBDriveLink.VendorLib = c:\windows\system32\fbclient.dll; 

My application does not use the embedded Firebird client. How can I solve this problem?

Answer 1

This error can be caused during attach to a database by Database Parameters Block including one of following options: isc_dpb_disable_wal, isc_dpb_set_read_only or dpb_set_db_replica. Former will throw the error unconditionally the rest only if the connection is not alone.

Also an attempt of dropping of the database with more than one connection will result in this error but I don't think that this is the case.

Answer 2

After I have removed from the IBAdvanced parameter of FDConnection the set_db_readonly=0, now my application can connect to the database while IBExpert or any other application is already connect to the same database.

I have included the set_db_readonly=0 parameter in the IBAdvanced parameter of the FDConnection as suggested by the help of FireDAC to set the database as read\write.