AWS DMS is a tool that supports both homogenous and heterogeneous migration, helping to migrate to aws cloud. During most of the migrations, the source and target table names remain the same, in which case the Mappings.json file is pretty simple. As an example (Oracle to PostgreSQL) { “rules”: [ { “rule-type”: “selection”, “rule-id”: “1”, […]
An important behavior in PostgreSQL to know about is the duplicate null values do not violate unique constraints. Oracle SQL> create table test (id number (2,0), country varchar(20) not null, state varchar(20) ); Table created. SQL> alter table test add constraint pk_test_id primary key (id); Table altered. SQL> alter table test add constraint uniq_test_cs unique […]
What is FillFactor in PostgreSQL? As per offical Doc — fillfactor (integer) The fillfactor for a table is a percentage between 10 and 100. 100 (complete packing) is the default. When a smaller fillfactor is specified, INSERT operations pack table pages only to the indicated percentage; the remaining space on each page is reserved for […]
A quick one !! Creating bucket failed with “IllegalLocationConstraintException” — [[email protected] ~]$ aws s3api create-bucket –bucket labtestrand –region us-west-2 An error occurred (IllegalLocationConstraintException) when calling the CreateBucket operation: The unspecified location constraint is incompatible for the region specific endpoint this request was sent to. Solution — [[email protected] ~]$ [[email protected] ~]$ aws s3api create-bucket –bucket labtestrand […]
I have been working on Oracle to Postgres migration and it has been a fun ride. One of the recent encounters during migration was performance issue in Postgres for a query, actually quite a simple query. SELECT count(*) AS num_incidents FROM audit_cs acs INNER JOIN audit_changes ac ON acs.audit_change_id = ac.audit_change_set WHERE acs.object_id=$1 AND ac.path […]