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Gateway Execution Process (Tibero to Oracle DBLink)

Document Type | Technical Information 

Field | Interface/Integration

Applicable Product Version | 7FS02PS

Document Number | TIITI002

 

Overview

The Gateway plays an important role in relaying database connections between the Tibero server and the Oracle server, reading configuration files and recording log files based on the $TBGW_HOME environment variable. This document provides guidance on Gateway information and the execution process. 

 

Method

$TBGW_HOME Directory Structure

$TBGW_HOME
+-- <DBMS Vendor Name>
 |-- config                   // Location for creating gateway configuration files
  |-- tbgw.cfg
 |-- log                      // Location for creating gateway-related log files
  |-- Log File

 

Gateway Methods

Category
Local Method
LISTENER Method
Applicable Target
Tibero and Oracle exist on the same server 
(Only UNIX-based systems supported)
Tibero and Oracle exist on different servers 
(UNIX, WINDOWS)
Features
- No need to start Gateway in advance 
- Gateway process created for each session connection 
- Process automatically terminates when session ends
- Gateway needs to be started manually in advance 
- Handles multiple requests via multi-threading 
- Listener must be set up on a separate server
 

Gateway Character Set Related Options

Option Name
Location
Description
CHARACTER_SET
tbgw.cfg
- If not explicitly set in the tbgw.cfg file, TB_NLS_LANG is referenced 
- If TB_NLS_LANG is also absent, Tibero's default charset is used 
(Tibero6: MSWIN949 / Tibero7: UTF8)
SKIP_CHAR_CONV
tbgw.cfg
Y : When delivering data from Oracle, converts format using TB_NLS_LANG before passing to Tibero N : Requests data from Oracle server using Tibero server's character set
BYTES_CHARSET
tbdsnr.tbr
- Java Gateway exclusive - When BYTES_CHARSET=Oracle character set is declared, even if Tibero and Oracle character sets differ, the Gateway processes the string in Oracle character set encoding independently of Gateway encoding and Tibero server character set, allowing Tibero to recognize it
_ALLOW_DIFF_CHARSET_INSTANCE
$TB_SID.tip
- Allows CTAS to execute normally even if Gateway and Tibero instance charsets differ (Y/N)
 

DBMS Vendor Specific Gateway Information

The table below lists the types of other DBMSs supported by Tibero for database link functions and the Gateway binary names.

 

Gateway Execution Process

  • tbsql โ†’ Gateway: Tibero DB client (tbsql) sends request to Gateway
  • Gateway โ†’ Oracle: Gateway forwards the query to Oracle and receives the result
[tbsql]  <--> [gateway] <--> [oracle]
[8629]  <--> [  9999   ] <--> [ 1521 ]

 

Gateway Communication Flow

  1. The Tibero server forwards the query requested to another DBMS to the Gateway
  2. The Gateway converts the requested query into a remote DB query (Oracle JDBC)
    The Gateway connects to the target DBMS and requests execution of the query received from the Tibero server
  3.  The target DB sends the result of the requested query back to the Gateway
  4. The Gateway converts the received response data into the format of the requesting DB and delivers it to Tibero

Gateway Communication Flow

Note
The following are points to refer to in case of errors.

Error Code
Cause
Resolution
TBR-2131: Generic I/O error.
Gateway process terminated
Gateway restart required (gw4orcl)
TBR-130092:(ORA-12541) 
TNS:no listener
Oracle listener has stopped or connection is unavailable
Check Oracle listener status and restart

 

 

 

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