Postgresql cluster initialization - postgresql

SQL distributes pre-initialized catalog cluster but for postgresql we need initialize cluster using initdb and a network service account. It fails in few cases and causing bit of misery!
Can initialize cluster ourselves and distribute pre-initialized cluster?
Thanks

The "cluster" (or data directory) depends on the operating system and the architecture. So a data directory that was initialized with initdb on a 32bit Linux will not work on a 64bit Windows.
But you don't need to do that. A service account is only necessary if you want to run PostgreSQL as a service.
You can easily use the ZIP distribution to install and start Postgres without the need for a full-fledge installation or a service account.
The steps to do so are:
Unzip the binaries
Run initdb pointing it to the directory where the database cluster should be created.
Run pg_ctl to start the server.
Note that the steps 2) and 3) must be run using the same user, otherwise the server will have no priviliges to write to the data directory.
These steps can easily be put into a batch file or shell script.

Hard to understand your question, but I think you are talking about the Windows installer for PostgreSQL. Right? What version, what installer, what about error messages, loggings, etc. ?
The installer can be found here.
SQL = database language, SQL Server =
Microsoft database product

Related

How to backup and restore PostgreSQL programmatically without using pg_dump and psql?

I have a kubernetes space where the PostgreSQL DB is on a different POD than the executor where my Typescrtipt code is being executed, which means that I do not have access to pg_dump and psql. Is there a typescript npm library which can backup and restore the DB programmatically and remotely or a special client which I can install in project so that I can use? I could not find such an mpm library or client on the internet.
Another thing that I can think of is some "universal" SQL script, which makes the backup and another one for the restore, if there is such a thing at all.

PostgreSQL log configuration on Ubuntu

I have PostgreSQL 9.5 (yes I know it's not supported anymore) installed on Ubuntu Server 18.04 using this instructions https://www.postgresql.org/download/linux/ubuntu/
I want to change path and separate log for every database. But it's configuret by package maintainer in such a way that it ignores log* settings in PostgreSQl configuration and uses some other way to log everything to files and I can't find out how. Currently it logs to /var/log/postgresql/postgresql-9.5-clustername.log. I want it to be /var/log/postgresql/clustername/database.log but I don't know where to configure it. In PostgreSQL log_destination is set to stderr
The Ubuntu packages have logging_collector disabled by default, so the log is not handled by PostgreSQL, but by the startup script.
However, there is no way in PostgreSQL to get a separate log file per database, so the only way to get what you want is to put the databases in individual clusters rather than into a single cluster.

How to load data from S3 to PostgreSQL RDS

I have a need to load data from S3 to Postgres RDS (around 50-100 GB) I don't have the option to use AWS Data Pipeline and I am looking for something similar to using the COPY command to load data in S3 into Amazon Redshift.
I would appreciate any suggestions on how I can accomplish this.
Originally, this answer was trying to use the S3 to Postgres RDS Functionality. That whole enterprise failed (see below).
The way I have finally been able to do this is:
Set-up an EC2 instance with psql installed (see below near end of post)
Copy the relevant CSVs to import from S3 to the local instance
Use the psql /copy command to import the files up
This last part is really, really important. If you use the SQL COPY command the entire RDS Postgres role structure will frustrate you to no end. It has a wonky SUPERRDSADMIN role which is not very super at all. However, if you use the psql /copy commany you apparently can do anything. I have confirmed this be the case and have started my uploads succesfully. I will come back and re-edit this post (time permitting) to add relevant documentation steps for the above.
Caveat Emptor: The post below was all the original work I had done trying to get this implemented. I don't want to bury the lead despite multiple efforts (including what can only be described as pathetic tech support from AWS) I don't believe that this feature is ready for prime time. Despite a very simple test environment, easy to replicate, AWS has not provided an effective way to not get the copy statement to crap out as follows:
The actual call to aws_s3.table_import_from_s3(...) is reporting a permission problem between RDS and S3. From my research work with psql this appears to be a C library, probably installed by AWS.
NOTICE: CURL error code: 28 when attempting to validate pre-signed URL, 1 attempt(s) remaining
NOTICE: HINT: make sure your instance is able to connect with S3.
S3 to Postgres RDS Functionality Now Added
On 2019-04-24 AWS released functionality allowing a Postgres RDS to load directly from S3. You can read the announcement here, and see the documentation page here.
I am sharing with the OP because this appears to be the AWS supported way of solving the question posed.
Key summary points:
Requires Postgres 11.1 or greater
Need access to psql and the ability to connect it to the RDS instance
Need to install the aws_s3 extension which pulls in aws_commons.
You can get to the S3 bucket by specifying credentials or by assigning IAM roles to RDS
It advertises supporting all of the same data formats as the postgres COPY command
It currently only appears to support a single file at a time (ie no regex)
The instructions are fairly detailed and provide a variety of paths to configuring (AWS CLI scripts, Console instructions, etc). Additionally, the option to use your IAM keys rather than have to set-up roles is nice.
I did not find a way to download just psql, so I had to bring down a full postgres install down to my mac, but that was no big deal with brew:
brew install postgres
and since the DB service does not get activated it is the quickest way to get psql.
Update: Decided that having psql on my mac was a security hole, port forwarding, etc. I found that there is a simple Postgres install available for AMI Linux 2 under the AMI Extras rubric. The install command is fairly simple on your ami instance type.
sudo amazon-linux-extras install postgresql10
psql is fairly easy to use, however, important to keep in mind that any instructions to psql itself are escaped by a \. Documentation on psql can be found here. Recommend going through it at least once before executing the AWS recommended scripts.
To the extent you run tight security and have access to your RDS instances seriously restricted (which I do) don't forget to open up the ports from your AMI instance running Postgres to your RDS instance.
If your preference is a GUI then you can try to use PGAdmin4. It is the AWS recommended way of connecting to RDS Postgres instances according to the docs. I was unable to get any of the SSH tunneling features to work (which is why I ended up doing the localhost SSH mapping that I used for psql). I also found it to be rather buggy in other ways. Reading reviews of the product it seems that version 4 may not be the stablest of releases.
http://docs.aws.amazon.com/redshift/latest/dg/t_loading-tables-from-s3.html
Use the COPY command to load a table in parallel from data files on
Amazon S3. You can specify the files to be loaded by using an Amazon
S3 object prefix or by using a manifest file.
The syntax to specify the files to be loaded by using a prefix is as
follows:
copy <table_name> from 's3://<bucket_name>/<object_prefix>'
authorization;
update
Another option is to mount s3 and use direct path to the csv with COPY command. I'm not sure If it will hold 100GB effectively, but worth of trying. Here is some list of options on software.
Yet another option would be "parsing" s3 file part by part with something described here to a file and COPY from named pipe, described here
And the most obvious option to just download file to local storage and use COPY I don't cover at all
Also worth of mentioning would be s3_fdw (status unstable). Readme is very laconic, but I assume you could create a foreign table leading to s3 file. Which itself means you can load data to other relation...

AWS DMS Streaming replication : Logical Decoding Output Plugins(test_decoding) not accessible

I'm trying to migrate a PostgreSQL DB persisted on cloud (on DO droplet) to RDS using AWS Database Migration Service (DMS).
I've successfully configured the replication instance and endpoints.
I've created a task with Migrate existing data and replicate ongoing changes. When I start the task it shows some error ERROR: could not access file "test_decoding": No such file or directory.
I've tried to create a replication slot manually on my DB console it throws the same error.
I've followed the procedures which was suggested on the DMS documentation for Postgres
I'm using PostgreSQL 9.4.6 on my source endpoint.
I presume that the problem is the output plugin test_decoding was not accessible to do the replication.
Please assist me to resolve this. Thanks in advance!
You must install postgresql-contrib additional supplied modules on Your source endpoint.
If it is installed, make sure, directory where test_decoding module located is the same with directory where PostgreSQL expect it.
In *nix, You can check module directory by command:
pg_config --pkglibdir
If it is not the same, copy module, or make symlink, or some other solution You prefer.

Postgresql in Active Directory Machine

I have a server in which Postgresql is installed. In this server I want to install the Microsoft Active Directory. Can I do this without a problems? Can I change the user that runs the Postgresql service without a problem?
When I install the AD all the machine users will be deleted so I need to create domain users to run that service.
It will work, but there could be performance issues since you're basically running two databases on the same machine.
It's a risk that the upgrade will remove the PostgreSQL service user. In this case, you will jus thave to create a new one and assign it to the service. Another option is to uninstall PostgreSQL (this will not uninstall the data), turn the machine into an AD controller, and then reinstall PostgreSQL (same version!). It will then pick up the old data directory automatically.