Search for a command to run...
![[OGG] Replicat is running too slowly](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fres%2Fhashnode%2Fimage%2Fupload%2Fv1759058040923%2F9281b2c6-9609-4e38-ba5d-f1ac890b85a7.jpeg&w=3840&q=75)
Ingeniero informático, Oracle ACE, DBA y Arquitecto OCI, con más de 15 años de experiencia en plataformas Oracle. Certificado en OCI Certified Architect Professional y OCI Migration and Integration Certified Professional.
No comments yet. Be the first to comment.
If you prefer to read in Spanish Spanish version. The goal of this post is as follows: To create a new database using the Oracle Database Configuration Assistant (DBCA) on 23ai. In this case, we defined an IaaS with Oracle Linux 9 on OCI. So, first t...
If you prefer to read in Spanish Spanish version. Today, let's talk about the steps to clone a PDB using RMAN Active Duplicate or DDL commands betweent differents CDB$Root. DDL Let's use a script in
![[OCI] Clone PDB](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fuploads%2Fcovers%2F65605419d28f19cc44df7ef1%2F4c20418f-c149-484c-a2b7-c30b4cfec47b.png&w=3840&q=75)
If you prefer to read in Spanish Spanish version. Today, let's see a little script in order to see quickly monitor jobs running into Oracle Database Cloud. Below, you can see the output our sh: At t
![[OCI] Check Jobs DBCli](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fuploads%2Fcovers%2F65605419d28f19cc44df7ef1%2F4007e787-d6ad-47d9-b238-d69a285383ab.png&w=3840&q=75)
If you prefer to read in Spanish Spanish version. Today, let's talk about the new join syntax available in the last realease 26ai. It was introduced to simplify our joins avoiding common mistakes, wri
![[26ai] JOIN_TO_ME](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fuploads%2Fcovers%2F65605419d28f19cc44df7ef1%2F49867547-f920-47a6-b11f-f5db511bcc73.png&w=3840&q=75)
If you prefer to read in Spanish Spanish version. Today, let's create an audit in order to clean up unused package/procedure/function in the database, with the porpuse of reducing the total amount of
![[26ai] Cleanup of Obsolete PL/SQL Objects](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fuploads%2Fcovers%2F65605419d28f19cc44df7ef1%2F64ada612-0048-411c-b9df-61b8825af6e7.png&w=3840&q=75)
If you prefer to read in Spanish Spanish version. Today, let's talk about a new Hybrid Read-Only open-mode in 26ai. When we set up this mode, our PDB is read-only mode for local users and read-write f
![[26ai] Hybrid Read-Only Mode PDB](/_next/image?url=https%3A%2F%2Fcdn.hashnode.com%2Fuploads%2Fcovers%2F65605419d28f19cc44df7ef1%2F23e8f92e-f89b-4746-930e-98156e3a1ec4.png&w=3840&q=75)
If you prefer to read in Spanish Spanish version.
Today, let’s look at a case where the Replicat process is running too slowly.
The situation with OGG when they notified me was as follows:
GGSCI 1> info all
Program Status Group Lag at Chkpt Time Since Chkpt
MANAGER RUNNING
EXTRACT RUNNING EXXX 00:00:06 00:00:09
REPLICAT RUNNING Rxxx 53:14:49 00:00:03
The Replicat process RXXX had a lag from the beginning that kept growing and never decreased, how come?
As a small note, OGG is running on version 19.1.0.0.4.
First, let’s check the processing statistics in minutes:
GGSCI 4> stats replicat Rxxx, totalsonly *.*, reportrate min
Sending STATS request to REPLICAT Rxxx...
Start of Statistics at 2025-09-28 00:23:05.
DDL replication statistics:
*** Total statistics since replicat started ***
Opees rations 104.00
Mapped operations 0.00
Unmapped operations 104.00
Other operations 0.00
Excluded operations 0.00
Errors 0.00
Retried errors 0.00
Discarded errors 0.00
Ignored errors 0.00
Cumulative totals for specified table(s):
*** Total statistics since 2025-09-27 23:19:02 ***
Total inserts/minute 0.00
Total updates/minute 0.00
Total deletes/minute 0.00
Total upserts/minute 0.00
Total discards/minute 13497.48
Total operations/minute 0.00
*** Daily statistics since 2025-09-28 00:00:00 ***
No database operations have been performed.
*** Hourly statistics since 2025-09-28 00:00:00 ***
No database operations have been performed.
*** Latest statistics since 2025-09-27 23:19:02 ***
Total inserts/minute 0.00
Total updates/minute 0.00
Total deletes/minute 0.00
Total upserts/minute 0.00
Total discards/minute 864456.00
Total operations/minute 0.00
End of Statistics.
Here, we can observe performance issues, such as a lower number of operations compared to other processes, or very few DML operations.
Let’s review the process definition:
REPLICAT Rxxx
useridalias ogg_xxxx
assumetargetdefs
DDL INCLUDE ALL
DDLERROR DEFAULT IGNORE
discardfile ./dirrpt/Rxxx.dsc, Append,megabytes 4000
REPERROR (0001,discard)
REPERROR (1403,discard)
TABLE SCHEMA.TABLE , TARGET PDB.SCHEMA.TABLE;
Here, we can see several points. On one hand, the source is a single instance, while the target is multitenant. On the other hand, I didn’t see the HANDLECOLLISIONS parameter in the definition.
The HANDLECOLLISIONS parameter, it’s very useful in order to iron out the conflicts when the replicat is running. These conflicts are known as collisions.
This parameter helps OGG manage collisions efficiently, such as:
Insert: OGG tries to insert a row when that already exists in the target.
Update: OGG tries to perform an update when the row doesn’t exists in the target.
Delete: OGG tries to remove a row when the row doesn’t exists in the target.
Alright, enough talking theory! Let’s get our hands dirty!
We modified the process in order to include the parameter. You can see it below:
REPLICAT Rxxx
useridalias ogg_xxxx
assumetargetdefs
DDL INCLUDE ALL
DDLERROR DEFAULT IGNORE
HANDLECOLLISIONS
discardfile ./dirrpt/Rxxx.dsc, Append,megabytes 4000
REPERROR (0001,discard)
REPERROR (1403,discard)
TABLE SCHEMA.TABLE , TARGET PDB.SCHEMA.TABLE;
After running the process again, I waited a few hours in order to observe the results.
As you can see below, the process is working better than before.
GGSCI 1> info all
Program Status Group Lag at Chkpt Time Since Chkpt
MANAGER RUNNING
EXTRACT RUNNING EXXX 00:00:02 00:00:07
REPLICAT RUNNING Rxxx 26:38:41 00:00:00
Let’s check the processing statistics again:
GGSCI 3> stats replicat Rxxx, totalsonly *.*, reportrate min
Sending STATS request to REPLICAT Rxxx...
Start of Statistics at 2025-09-28 12:19:43.
DDL replication statistics:
*** Total statistics since replicat started ***
Operations 4804.00
Mapped operations 5.00
Unmapped operations 4799.00
Other operations 0.00
Excluded operations 0.00
Errors 7.00
Retried errors 0.00
Discarded errors 0.00
Ignored errors 6.00
Cumulative totals for specified table(s):
*** Total statistics since 2025-09-28 00:26:27 ***
Total inserts/minute 63670.08
Total updates/minute 0.00
Total deletes/minute 54358.40
Total upserts/minute 0.00
Total discards/minute 0.00
Total operations/minute 118028.47
Total insert collisions/minute 63670.08
Total delete collisions/minute 31318.92
*** Daily statistics since 2025-09-28 00:26:27 ***
Total inserts/minute 63670.08
Total updates/minute 0.00
Total deletes/minute 54358.40
Total upserts/minute 0.00
Total discards/minute 0.00
Total operations/minute 118028.47
Total insert collisions/minute 63670.08
Total delete collisions/minute 31318.92
*** Hourly statistics since 2025-09-28 12:00:00 ***
Total inserts/minute 7272.71
Total updates/minute 0.00
Total deletes/minute 421092.52
Total upserts/minute 0.00
Total discards/minute 0.00
Total operations/minute 428365.24
Total insert collisions/minute 7272.71
Total delete collisions/minute 421092.52
*** Latest statistics since 2025-09-28 00:26:27 ***
Total inserts/minute 45413289.00
Total updates/minute 0.00
Total deletes/minute 38771646.00
Total upserts/minute 0.00
Total discards/minute 0.00
Total operations/minute 84184935.00
Total insert collisions/minute 45413289.00
Total delete collisions/minute 22338520.00
End of Statistics.
Here, we can observe several points:
The number of operations has exceeded 4000 instead of 104.
The dml workflow is working properly.
The performance issue has been worked out.
I hope you enjoyed reading this post :)