In one of the the earlier posts we had discussed the GoldenGate 12c Integrated Apply or Integrated Replicat feature. It enables high volume transactions to be applied in parallel.
But it was only supported for Oracle databases and also required to be version 11.2.0.4 and higher.
The Coordinated Replicat feature is new in GoldenGate 12c where the Replicat is multi-threaded and a single replicat instance, multiple threads read the trail independently and apply transactions in parallel. One coordinator thread spawns and coordinates one or more threads that execute replicated SQL operations in parallel.
The main difference between the Integrated Replicat and the Coordinated Replicat is that while in case of the Integrated Replicat, GoldenGate will add (or remove) additional apply server processes depending on the workload, in case of Coordinated Replicat it is user defined partitioning of the workload so as to apply high volume transactions concurrently and in parallel. This is done via the parameter THREADS and MAXTHREADS which we will discuss in this post using an example.
In earlier versions, scalability was enabled by fanning out the work to multiple replicats when the work could not be handled by a single replicat – but this required us to have multiple extracts, data pumps and replicat groups (and parameter files as well).
For example we had to create three separate replicat groups and use the RANGE parameter:
REP1.PRM
MAP sales.acct, TARGET sales.acct, FILTER (@RANGE (1, 3, ID));
REP2.PRM
MAP sales.acct, TARGET sales.acct, FILTER (@RANGE (2, 3, ID));
REP3.PRM
MAP sales.acct, TARGET sales.acct, FILTER (@RANGE (3, 3, ID))
Now in Goldengate 12c Coordinated replicat or delivery, there is a single replicat parameter file and additional replicat groups are created automatically and a single coordinator process or thread spawns additional threads and assigns individual workloads to each thread. Partitioning of workload is done via the THREADRANGE parameter used in the MAP statement.
For example now we require just one single replicat parameter file:
REP.PRM
MAP sales.acct, TARGET sales.acct, THREADRANGE(1-3, ID));
So if the target database is an Oracle version that does not support integrated Replicat, or if it is a non-Oracle database, we can use a coordinated Replicat feature to more or less achieve the same benefits of Integrated Replicat which is to provide higher throughput of transaction application on the target database by processing workload in parallel.
Let us now look at an example of using a Coordinated Replicat.
As in the case of the previous example using Integrated Replicat, the source database is an Oracle 12c Pluggable Database called SALES and we are replicating to another Oracle 12c Pluggable Database called SALES_DR.
We have created the table MYOBJECTS in both the source and target databases and have already enabled supplemental logging at the schema level.
SQL> create table myobjects as select * from all_objects where 1=2; Table created. SQL> alter table myobjects add constraint pk_myobjects primary key (object_id); Table altered. SQL> grant all on myobjects to C##GGADMIN; Grant succeeded.
On the source we have created the Extract and Data Pump groups – we are using Integrated Extract in this case.
Register the integrated extract GGSCI (orasql-001-dev.mydomain) 6> DBLOGIN USERIDALIAS gg_root Successfully logged into database CDB$ROOT. GGSCI (orasql-001-dev.mydomain) 7> REGISTER EXTRACT myext1 DATABASE CONTAINER (sales) Extract MYEXT1 successfully registered with database at SCN 3669081. Add the Integrated Extract and Data Pump GGSCI (orasql-001-dev.mydomain) 8> ADD EXTRACT myext1 INTEGRATED TRANLOG, BEGIN NOW EXTRACT added. GGSCI (orasql-001-dev.mydomain) 9> ADD EXTTRAIL ./dirdat/lt EXTRACT myext1 EXTTRAIL added. GGSCI (orasql-001-dev.mydomain) 10> ADD EXTRACT mydp1 EXTTRAILSOURCE ./dirdat/lt BEGIN NOW EXTRACT added. GGSCI (orasql-001-dev.mydomain) 11> ADD RMTTRAIL ./dirdat/rt EXTRACT mydp1 RMTTRAIL added. Edit the Integrated Extract Parameter File GGSCI (orasql-001-dev.mydomain) 11> edit params myext1 EXTRACT myext1 SETENV (ORACLE_SID='condb2') USERIDALIAS gg_root LOGALLSUPCOLS UPDATERECORDFORMAT COMPACT EXTTRAIL ./dirdat/lt SOURCECATALOG sales TABLE sh.myobjects; Edit the Data Pump Parameter File GGSCI (orasql-001-dev.mydomain) 12> edit params mydp1 EXTRACT mydp1 SETENV (ORACLE_SID='condb2') USERIDALIAS gg_owner RMTHOST orasql-001-test, MGRPORT 7809 RMTTRAIL ./dirdat/rt SOURCECATALOG sales TABLE sh.myobjects;
On the target, add the Coordinated Replicat
GGSCI (orasql-001-test.mydomain) 1> DBLOGIN USERIDALIAS gg_sales
Successfully logged into database SALES_DR.
GGSCI (orasql-001-dev.mydomain) 4> add replicat rep1, coordinated, EXTTRAIL ./dirdat/rt, maxthreads 5
REPLICAT (Coordinated) added.
GGSCI (orasql-001-dev.mydomain) 1> view params rep1
REPLICAT rep1
SETENV (ORACLE_SID='condb2')
USERIDALIAS gg_sales
ASSUMETARGETDEFS
MAP sales.sh.myobjects, TARGET sales_dr.sh.myobjects,
THREADRANGE(1-5, OBJECT_ID));
GGSCI (kens-orasql-001-dev.corporateict.domain) 5> start replicat rep1
Sending START request to MANAGER ...
REPLICAT REP1 starting
GGSCI (kens-orasql-001-dev.corporateict.domain) 6> info replicat rep1
REPLICAT REP1 Last Started 2014-01-23 10:38 Status RUNNING
COORDINATED Coordinator MAXTHREADS 5
Checkpoint Lag 00:00:00 (updated 00:00:04 ago)
Process ID 25811
Log Read Checkpoint File ./dirdat/rt000000
First Record RBA 0
GGSCI (kens-orasql-001-dev.corporateict.domain) 8> info replicat rep1 detail
REPLICAT REP1 Last Started 2014-01-23 10:38 Status RUNNING
COORDINATED Coordinator MAXTHREADS 5
Checkpoint Lag 00:00:00 (updated 00:00:00 ago)
Process ID 25811
Log Read Checkpoint File ./dirdat/rt000000
First Record RBA 1642
We now populate the source table with some data and check if the extract has captured the change data
SQL> insert into myobjects
2 select * from all_objects;
77694 rows created.
SQL> commit;
Commit complete.
GGSCI (kens-orasql-001-test.corporateict.domain) 1> stats extract ext1 latest
Sending STATS request to EXTRACT EXT1 ...
Start of Statistics at 2014-01-23 10:41:54.
Output to ./dirdat/lt:
Extracting from SALES.SH.MYOBJECTS to SALES_DR.SH.MYOBJECTS:
*** Latest statistics since 2014-01-23 10:41:33 ***
Total inserts 77694.00
Total updates 0.00
Total deletes 0.00
Total discards 0.00
Total operations 77694.00
End of Statistics.
We can now see that the Replicat has spawned 5 additional threads (because we had specified MAXTHREADS 5) and we see the addtional replicat groups have been created (REP1001 to REP1005).
GGSCI (orasql-001-dev.mydomain) 9> info replicat rep1 detail
REPLICAT REP1 Last Started 2014-01-23 10:48 Status RUNNING
COORDINATED Coordinator MAXTHREADS 5
Checkpoint Lag 00:03:11 (updated 00:00:00 ago)
Process ID 26831
Log Read Checkpoint File ./dirdat/rt000000
2014-01-23 10:46:29.747584 RBA 28181513
Lowest Log BSN value:
Active Threads:
ID Group Name PID Status Lag at Chkpt Time Since Chkpt
1 REP1001 26838 RUNNING 00:00:00 00:00:20
2 REP1002 26839 RUNNING 00:00:00 00:00:20
3 REP1003 26840 RUNNING 00:00:00 00:00:20
4 REP1004 26841 RUNNING 00:00:00 00:00:20
5 REP1005 26842 RUNNING 00:00:00 00:00:20
GGSCI (orasql-001-dev.mydomain) 2> info replicat rep1001
REPLICAT REP1001 Last Started 2014-01-23 10:48 Status RUNNING
COORDINATED Replicat Thread Thread 1
Checkpoint Lag 00:00:00 (updated 00:00:05 ago)
Process ID 26838
Log Read Checkpoint File ./dirdat/rt000000
2014-01-23 10:49:24.008242 RBA 56361384
About 77000 rows were inserted in the target table and we can see that the workload has been distributed by the replicat coordinator process among the 5 threads – so each thread has processed about 15000 rows each.
GGSCI (orasql-001-dev.mydomain) 2> stats replicat rep1001
Sending STATS request to REPLICAT REP1001 ...
Start of Statistics at 2014-01-23 10:51:44.
Replicating from SALES.SH.MYOBJECTS to SALES_DR.SH.MYOBJECTS:
*** Total statistics since 2014-01-23 10:49:31 ***
Total inserts 15748.00
Total updates 0.00
Total deletes 0.00
Total discards 0.00
Total operations 15748.00
GGSCI (orasql-001-dev.mydomain) 4>
GGSCI (orasql-001-dev.mydomain) 3> stats replicat rep1005
Sending STATS request to REPLICAT REP1005 ...
Start of Statistics at 2014-01-23 10:52:09.
Replicating from SALES.SH.MYOBJECTS to SALES_DR.SH.MYOBJECTS:
*** Total statistics since 2014-01-23 10:49:31 ***
Total inserts 15640.00
Total updates 0.00
Total deletes 0.00
Total discards 0.00
Total operations 15640.00
