SharePlex replication between two instances on the same host

Posted in: Oracle, Technical Track

Several days ago I was asked a question about SharePlex and should verify behaviour before providing the answer. I had one linux VM with two databases and needed to setup replication between them. One of them (orcl) was a target 12c EE database while the second one was a source 10g SE. Accordingly, I should use two different versions of SharePlex to mimic the questionable behaviour, so I should have two different SharePlex instances talking to each other on the same host machine. It worked pretty well for, as an example, GoldenGate, where you just setup different ports for manager processes. However, in SharePlex all the instances participating in a configuration should use the same port. The SharePlex documentation states:
“Important! The SharePlex port number must be the same one on all machines in the replication configuration so that they can communicate through TCP/IP connections.”

Of course you cannot use the same port on the same network interface for two independent SharePlex processes working from different homes. In addition, SharePlex is not asking you about a hostname either during installation, or when you start it.
In my case I had 2 interfaces in different subnets on my VM, and I could use them for my replication. But how should I tell to the SharePlex to use one or the other? The answer was simple. You should use “SP_SYS_HOST_NAME” parameter as the environment variable for your shell. Here is how I’ve done that.
I added two new hostnames for those interfaces to my /etc/hosts file to be used for my SharePlex instances:

[root@sandbox ~]$ cat /etc/hosts | grep splex
10.177.130.58 splexhost
172.16.128.10 splexstor
[root@sandbox ~]$

I unzipped SharePlex 8.6.3 for Oracle 10 and prepared installation. By default the installer will pick up the hostname automatically and use it during installation.
Here is my hostname and it is not what I want to use for my first SharePlex instance:

[oracle@sandbox ~]$ hostname
sandbox.localdomain
[oracle@sandbox ~]$ ping sandbox.localdomain
PING sandbox.localdomain (127.0.0.1) 56(84) bytes of data.
64 bytes from sandbox.localdomain (127.0.0.1): icmp_seq=1 ttl=64 time=0.058 ms
64 bytes from sandbox.localdomain (127.0.0.1): icmp_seq=2 ttl=64 time=0.061 ms
^C
--- sandbox.localdomain ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1468ms
rtt min/avg/max/mdev = 0.058/0.059/0.061/0.007 ms
[oracle@sandbox ~]$

What you need to do is to setup an environment variable SP_SYS_HOST_NAME. I wanted the first SharePlex listening and working on hostname splexhost using default port 2100. I should also define proper Oracle home and Oracle database SID during installation. I used standard Oracle utility oraenv to have Oracle variables setup. Here is how I started installation for the source:

[oracle@sandbox ~]$ export SP_SYS_HOST_NAME=splexhost
[oracle@sandbox ~]$ . oraenv
ORACLE_SID = [test] ?
The /u01/app/oracle/product/10.2.0/sehome_1/bin/orabase binary does not exist
You can set ORACLE_BASE manually if it is required.
[oracle@sandbox ~]$ cd /u01/distr/SharePlex
[oracle@sandbox SharePlex]$ ll
total 96736
-rwxr-xr-x. 1 oracle oinstall 99056391 Jan 11 21:56 SharePlex-8.6.3-b171-oracle100-rh-40-amd64-m64.tpm
[oracle@sandbox SharePlex]$ ./SharePlex-8.6.3-b171-oracle100-rh-40-amd64-m64.tpm
Unpacking ..................................................................
..........................................................................

During the installation I provided directories for program and variable files, port number and information about ORACLE_SID and ORACLE_HOME. Everything went smoothly. I finished the installation by running the “ora_setup” utility creating necessary schema and objects in the source database.
For target I used the same strategy setting up Oracle variables by “oraenv” and exporting explicitly SP_SYS_HOST_NAME=splexstor. The installation worked out without any problems and I got two SharePlex instances installed to different directories.
To start a SharePlex home for a certain IP address and interface you need to explicitly setup SP_SYS_HOST_NAME to an appropriate value. Let’s see how it’s been done for source.

[oracle@sandbox ~]$ export SP_SYS_HOST_NAME=splexhost
[oracle@sandbox ~]$ . oraenv
ORACLE_SID = [test] ?
The /u01/app/oracle/product/10.2.0/sehome_1/bin/orabase binary does not exist
You can set ORACLE_BASE manually if it is required.
[oracle@sandbox ~]$ cd /u01/sp10/bin
[oracle@sandbox bin]$ telnet splexhost 2100
Trying 10.177.130.58...
telnet: connect to address 10.177.130.58: Connection refused

[oracle@sandbox bin]$ nohup /u01/sp10/bin/sp_cop -usp10 &
[1] 2023
[oracle@sandbox bin]$ nohup: ignoring input and appending output to `nohup.out'

[oracle@sandbox bin]$ telnet splexhost 2100
Trying 10.177.130.58...
Connected to splexhost.
Escape character is '^]'.
^] telnet> q
Connection closed.
[oracle@sandbox bin]$

For target you have to adjust your environment variables accordingly and do the same.

[oracle@sandbox ~]$ export SP_SYS_HOST_NAME=splexstor
[oracle@sandbox ~]$ . oraenv
ORACLE_SID = [test] ? orcl
The Oracle base has been set to /u01/app/oracle
[oracle@sandbox ~]$cd /u01/sp12/bin
[oracle@sandbox bin]$ nohup /u01/sp12/bin/sp_cop -usp12 &
[1] 2066
[oracle@sandbox bin]$ nohup: ignoring input and appending output to `nohup.out'

[oracle@sandbox bin]$

As result we have two SharePlex instances running on the same host and talking to each other. Now we can create a sample replication. In the database schema “splex” created by “ora_setup” utility we have DEMO_SRC and DEMO_DST tables. SharePlex is using those tables for a demo replication. We can use them too and see how it works in our case. We can either modify a default pre-created sample configuration “ORA_config” or we can create a new one. I’ve created a new config “sample” on my source SharePlex and activated it:

sp_ctrl (splexhost:2100)> list config

File Name State Datasource
-------------------------------------------------- ---------- ---------------
ORA_config Inactive o.SOURCE_SID
Last Modified At: 17-May-16 11:17 Size: 151

sp_ctrl (splexhost:2100)> create config sample

The command opens default editor and you can write your configuration.
Here is what I put to my “sample” config.

datasource:o.test

#source tables target tables routing map

splex.demo_src splex.demo_dest splexstor@o.orcl

Now we can activate config.

sp_ctrl (splexhost:2100)> activate config sample

sp_ctrl (splexhost:2100)> list config

File Name State Datasource
-------------------------------------------------- ---------- ---------------
ORA_config Inactive o.SOURCE_SID
Last Modified At: 17-May-16 11:17 Size: 151

sample Active o.test
Last Modified At: 17-May-16 11:30 Size: 134 Internal Name: .conf.1

sp_ctrl (splexhost:2100)>

Now we can see all the processes running :

On the source:

sp_ctrl (splexhost:2100)> lstatus

Detailed Status for splexhost
Process State PID Running Since
--------------- ------------------------------ -------- --------------------
Cop Running 2023 17-May-16 11:24:39
Capture Running 2250 17-May-16 11:30:53
Data/Host: o.test
Read Running 2279 17-May-16 11:30:53
Data/Host: o.test
Export Running 2304 17-May-16 11:30:56
Data/Host: splexstor
Queue Name: splexhost
Cmd & Ctrl Running 2581 17-May-16 11:40:39
Data/Host: splexhost

On the target:

sp_ctrl (splexstor:2100)> lstatus

Detailed Status for splexstor
Process State PID Running Since
--------------- ------------------------------ -------- --------------------
Cop Running 2066 17-May-16 11:26:23
Import Running 2305 17-May-16 11:30:56
Data/Host: splexhost
Queue Name: splexhost
Post Running 2306 17-May-16 11:30:56
Data/Host: o.test-o.orcl
Queue Name: splexhost
Cmd & Ctrl Running 2533 17-May-16 11:38:18
Data/Host: splexstor

Let’s insert a row on the source :

test>  insert into splex.demo_src values ('JIM', '8001 Irvine Center Drive', '949-754-8000');

1 row created.

test> commit;

Commit complete.

test>

And we can see the row was successfully replicated to target:

orcl> select * from splex.demo_dest;

NAME ADDRESS PHONE#
------------------------------------------------------------ ------------------------------------------------------------ ------------
JIM 8001 Irvine Center Drive 949-754-8000

orcl>

As you can see, we were able to use one box to replicate data between two different databases, using two different SharePlex installations. The idea was simple and clear from the start, but I couldn’t find enough information in the installation guide for the SP_SYS_HOST_NAME parameter except documentation about configuring it for cluster installation. The parameter was documented in the reference section of documentation, though in reality it was not.
It could be even better if we could place the parameter inside, and not think about setting variables, but unfortunately setting the parameter in the “paramdb” didn’t work for me. Even having the parameter, you still need to setup your environment variable SP_SYS_HOST_NAME=your_host_name for non default hostname. I hope the article may help somebody save a bit of time.

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About the Author

Regarded by his peers as an Oracle guru, Gleb is known for being able to resolve any problem related to Oracle. He loves the satisfaction of troubleshooting, and his colleagues even say that seeking Gleb’s advice regarding an issue is more efficient than looking it up. Gleb enjoys the variety of challenges he faces while working at Pythian, rather than working on the same thing every day. His areas of speciality include Oracle RAC, Exadata, RMAN, SQL tuning, high availability, storage, performance tuning, and many more. When he’s not working, running, or cycling, Gleb can be found reading.

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