Oracle Shared Server: Processes, Configuration, and How to Verify

Shared Server (formerly MTS) is a database-side architecture that lets many client sessions share a pool of server processes. You do not start a separate “shared server executable”. Instead, the instance spawns shared server and dispatcher processes when parameters are set.

What actually runs?

• Dispatchers — accept connections and queue requests.
  UNIX/Linux process names: ora_D000_<SID>, ora_D001_…
• Shared servers — pull from queues and execute user calls.
  UNIX/Linux process names: ora_S000_<SID>, ora_S001_…
• Listener — tnslsnr advertises the service/handlers used by dispatchers.
• Windows — these are threads inside oracle.exe; you will also see tnslsnr.exe.

How to enable (DBA)

-- Example: enable 4 shared servers and one TCP dispatcher
ALTER SYSTEM SET shared_servers = 4 SCOPE=BOTH;
ALTER SYSTEM SET dispatchers = '(PROTOCOL=TCP)(SERVICE=orclXDB)' SCOPE=BOTH;

How to verify from SQL*Plus

-- Parameters
SHOW PARAMETER shared_servers
SHOW PARAMETER dispatchers

-- Runtime views
SELECT name, network, status, messages FROM v$dispatcher ORDER BY name;
SELECT name, status, requests, bytes FROM v$shared_server ORDER BY name;

How to verify via the listener

lsnrctl services

You should see service handlers showing dispatchers in addition to (or instead of) dedicated handlers.

OS checks

Linux/UNIX

ps -ef | egrep 'ora_(D|S)[0-9]+|tnslsnr' | grep -v grep

Windows

tasklist /FI "IMAGENAME eq tnslsnr.exe"
sc query type= service state= all | findstr /i "OracleService OracleOra TNSListener"

When to use Shared Server

• Many concurrent, mostly idle/light sessions (forms, web, report viewers).
• You want to reduce per-session PGA/process footprint on the host.

Prefer Dedicated Server for long-running, CPU-heavy, or bulk workloads.

Common misconceptions (fixed)

• “Shared Server executable” — incorrect; the architecture is controlled by parameters and instance processes.
• EMCC/OMC tie-in — Enterprise Manager (on-prem) or OMC (cloud) are management layers; they do not replace or define Shared Server.
• Finding binaries — the relevant binaries are the usual ones: oracle/oracle.exe and tnslsnr/tnslsnr.exe.

Summary: Configure Shared Server with shared_servers and dispatchers; verify using parameters, V$ views, lsnrctl services, and OS process checks. There is no separate executable to locate.

Title: Oracle Shared Server: Processes, Configuration, and How to Verify (No Separate Executable)

Meta Description: There is no standalone “Shared Server executable.” Learn how Shared Server works in Oracle, how to enable it with parameters, and how to verify via V$ views, lsnrctl, and OS checks on Linux/UNIX and Windows.