I'm trying to connect Tarantool Docker Image to local PostgreSQL, to replicate some test data, and ran into the following problems:
It seems there is no CL (except Tarantool console) to check which
files are in place (exec bin/bash fails)
pg = require('pg') leads to
an error: "init.lua:4: module 'pg.driver' not found", despite the
presence of the pg module in the Docker description
I have doubts about how to replicate efficiently 4 tables, and
relations between them, to the container from outside Postgres
Does anyone know sources to dig in and find solutions to those problems? Any direction would be greatly appreciated.
docker exec -ti tnt_container sh
the issue. You should find an older base image or build it yourself.
This is PostgreSQL-related doubts. You may pass batches of data to pg functions or use intermediate application to transfer data via COPY. It looks like tarantool's pg driver does not support COPY.
Related
This question already has answers here:
Export and import table dump (.sql) using pgAdmin
(6 answers)
Closed 1 year ago.
Let I first state that I am not a DBA-guy but I do have a question regarding restoring remote databases using PG Admin.
I have this PG Admin tool (v4.27) running in a Docker container and I use this portal to maintain two separate Postgress databases, both running in a Docker container as well. I installed PG Agent in both database containers and run scheduled daily backup's, defined via PG Admin and stored in the container of each corresponding databases. So far so good.
Now I want to restore one of these databases by using the latest daily backup file (*.sql), but the Restore Dialog of PG Admin only looks for files stored locally (the PG Admin container)?
Whatever I tried or searched for on the internet, to me it seems not possible to show a list of remote backup files in PG Admin or run manually a remote SQL file. Is this even possible in PG Admin? Running psql in the query editor is not possible (duh ...) and due to not finding the remote SQL-restore file I have no clue how to run this code within PG Admin on the remote corresponding database container.
The one and only solution so far I can think of, is scheduling a restore which has no calendar and should be triggered manually when needed, but it's not the prettiest solution.
Do I miss something or did I overlook the right documentation or have I created a silly, unmaintainable solution?
Thanks in advance for thinking along and kind regards,
Aad Dijksman
You cannot restore a plain format dump (an SQL script) with pgAdmin. You will have to use psql, the command line client.
COPY statements and data are mixed in such a dump, and that would make pgAdmin choke.
The solution by #Laurenz Albe points out that it is best to use the command line psql here, and that would be my first go-to.
However, if for whatever reason you don't have access to the command line and are only able to connect to this database via pgadmin, there is another solution which you can find here:
Export and import table dump (.sql) using pgAdmin
I recommend looking at the solution by Tomas Greif.
I'm currently in the process of switching my cloud server from Heroku to Digital Ocean. However is there a way to migrate the database from the heroku server to the digital ocean one? I use postgresql for my database
I hope you already got a solution, but in case you didn’t, I’ll provide a simple guide on how I did it. I am going to assume that you have already created a postgres database on digitalocean. Also you need navigate to your project directory and log in to heroku using the heroku cli. And, you need to have postgresql installed or a psql client. Installing postgresql would do it as it comes with psql.
Step 1: Create a backup and download the backup from heroku postgres
heroku pg:backups:capture --app <app_name>
heroku pg:backups:download --app <app_name>
The first command will create a backup of your database and the second command will download it to your current directory, its a .dump file. If you would like to read more, here is an article.
Step 2: Connect to your remote (digital ocean’s) database using psql
Before you can do this, you need to go and add your machine you are connecting from to the list of database’s list of trusted sources, If you don’t, you’ll get a Connection Timed Out error. That’s because the database’s firewall doesn’t allow you to connect to the database from your local machine or resource (for security reasons).
Step 3: Import the Database
pg_restore -d "postgresql://<database_username>:<database_password>#<host>:<port>/<database>?sslmode=require" --jobs 4 -c "/path/to/dump_file.dump"
This will import your database from your dump file. Just substitute the variables will your connection parameters that you get from your dashboard. If you would like to read more, here is another article for this step.
Another thing to make clear is, sometimes, you will see some harmless error messages when running this command, but it will push through anyway. To learn more about pg_restore read this article.
And that’s it, your database has been migrated. Now, can you confirm it worked?, well, as for me, I used pgAdmin to connect to the remote database and I saw the tables and data as expected.
Hope this helps anyone with the same problem :)
I'm relatively new to dockers, but I'm kind of wondering whether is it possible for me to create two master-slave postgres containers. I can do it on virtual machines, but I'm a bit confused on the one in docker.
If it's possible can someone please point me to right directions?
I have tried to docker exec -it, but all the files are all missing and I cannot edit the files inside.
Since you are new to Docker, and you wish to get up and running quickly, you can try using Bitnami's images, which allow you to specify a POSTGRESQL_REPLICATION_MODE environment variable, which will allow you to designate a container as a standby/slave.
Just save their docker-compose-replication.yml as docker-compose.yml in the director of your choice, run docker-compose up -d, and it will pull the necessary image and set everything up for you quickly.
However, I would highly encourage you to tinker on your own to learn how Docker works. Specifically, you could just use the community Postgres image, and then write your own entrypoint.sh file (along with any additional helper files as necessary), and customize the setup to your requirements.
Disclosure: I work for EnterpriseDB (EDB)
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...
I'd like to monitor the queries getting sent to my database from an application. To that end, I've found pg_stat_activity, but more often then not, the rows which are returned read " in transaction". I'm either doing something wrong, am not fast enough to see the queries come through, am confused, or all of the above!
Can someone recommend the most idiot-proof way to monitor queries running against PostgreSQL? I'd prefer some sort of easy-to-use UI based solution (example: SQL Server's "Profiler"), but I'm not too choosy.
PgAdmin offers a pretty easy-to-use tool called server monitor
(Tools ->ServerStatus)
With PostgreSQL 8.4 or higher you can use the contrib module pg_stat_statements to gather query execution statistics of the database server.
Run the SQL script of this contrib module pg_stat_statements.sql (on ubuntu it can be found in /usr/share/postgresql/<version>/contrib) in your database and add this sample configuration to your postgresql.conf (requires re-start):
custom_variable_classes = 'pg_stat_statements'
pg_stat_statements.max = 1000
pg_stat_statements.track = top # top,all,none
pg_stat_statements.save = off
To see what queries are executed in real time you might want to just configure the server log to show all queries or queries with a minimum execution time. To do so set the logging configuration parameters log_statement and log_min_duration_statement in your postgresql.conf accordingly.
pg_activity is what we use.
https://github.com/dalibo/pg_activity
It's a great tool with a top-like interface.
You can install and run it on Ubuntu 21.10 with:
sudo apt install pg-activity
pg_activity
If you are using Docker Compose, you can add this line to your docker-compose.yaml file:
command: ["postgres", "-c", "log_statement=all"]
now you can see postgres query logs in docker-compose logs with
docker-compose logs -f
or if you want to see only postgres logs
docker-compose logs -f [postgres-service-name]
https://stackoverflow.com/a/58806511/10053470
I haven't tried it myself unfortunately, but I think that pgFouine can show you some statistics.
Although, it seems it does not show you queries in real time, but rather generates a report of queries afterwards, perhaps it still satisfies your demand?
You can take a look at
http://pgfouine.projects.postgresql.org/