DMS - Update limitations and preparing oracle source database page

Updated limitations page as per the changes in the PR: #6952

Author: nidhibhammar

advocacy_docs/edb-postgres-ai/hybrid-manager/using_hybrid_manager/migration/limitations.mdx

@@ -26,7 +26,7 @@ These are the known issues, limitations, and notes for:
 
 A limited number of Oracle data types and features aren't supported by EDB Data Migration Service (EDB DMS).
 
-See the [Debezium documentation](https://debezium.io/documentation/reference/2.2/connectors/oracle.html#oracle-data-type-mappings) for detailed comments on supported data types. 
+See the [Debezium documentation](https://debezium.io/documentation/reference/2.2/connectors/oracle.html#oracle-data-type-mappings) for detailed comments on supported data types.
 
 Unsupported Oracle data types include:
 
@@ -44,6 +44,8 @@ EDB DMS supports replicating Oracle tables that contain BLOB, CLOB, or NCLOB col
 
 `BINARY_FLOAT` and `BINARY_DOUBLE` types in Oracle that might contain `Nan`, `+INF`, and `-INF` values are not supported by EDB DMS.
 
+For text field types like `VARCHAR` and `CLOB` in Oracle, values containing null character(0x00) are not supported by EDB DMS.
+
 ### Oracle 21c databases
 
 The Data Migration Service Reader and Writer support migrating Oracle 21c databases. However, Migration Portal doesn't. This means that to migrate 21c databases, you must manually perform the schema migration.
@@ -64,11 +66,38 @@ The EDB DMS doesn't support migrating tables with columns that have user-defined
 -   XML
 -   POINT
 -   LTREE
+-   TSVECTOR
+
+### TSVECTOR type migration workaround
+
+This workaround can be used to handle `TSVECTOR` columns during a migration, using the following `messages` table as an example:
+
+```sql
+CREATE TABLE messages (
+    title       text,
+    body        text,
+    tsv         tsvector
+);
+```
+
+The first option is to create a trigger that automatically updates the `tsvector` field. This trigger should be created on the target table before migration and configured to fire before INSERT or UPDATE statements.
+
+```sql
+CREATE TRIGGER tsvectorupdate BEFORE INSERT OR UPDATE
+ON messages FOR EACH ROW EXECUTE FUNCTION
+tsvector_update_trigger(tsv, 'pg_catalog.english', title, body);
+```
+
+Since this trigger will not compute the `tsvector` field for existing rows, you can run the following UPDATE statement after the migration is complete to populate the column for all migrated data:
+
+```sql
+UPDATE messages SET tsv = to_tsvector('english', CONCAT(title, ' ', body)) WHERE tsv IS NULL;
+```
 
 ### Incorrect failure messages
 
-The `postgresConfigValidation.sh` script referenced in [Preparing Postgres database sources](/edb-postgres-ai/hybrid-manager/using_hybrid_manager/migration/migration_guides/self_managed_pg_to_hm_managed/preparing_source_pg_db/) incorrectly reports failures for the `max_wal_size` database parameter check and for the replication slot check. 
+The `postgresConfigValidation.sh` script referenced in [Preparing Postgres database sources](/edb-postgres-ai/hybrid-manager/using_hybrid_manager/migration/migration_guides/self_managed_pg_to_hm_managed/preparing_source_pg_db/) incorrectly reports failures for the `max_wal_size` database parameter check and for the replication slot check.
 
-The script reports a failure for the `max_wal_size` check, if the parameter is set to a value lower than 8 GB. Although this is a recommended setting for many production workloads, setting the parameter to a lower value doesn't prevent a migration from being performed. 
+The script reports a failure for the `max_wal_size` check, if the parameter is set to a value lower than 8 GB. Although this is a recommended setting for many production workloads, setting the parameter to a lower value doesn't prevent a migration from being performed.
 
 In addition, the Postgres configuration validation script also performs a check to see if a replication slot with a slot name matching the migration user/role was created. This is an outdated check that is no longer needed because the EDB DMS Reader automatically creates and manages the required replication slot. You can ignore the failure message related to the replication slot. The check will be removed in a future version of the `postgresConfigValidation.sh` script.