pg_dump while inserting data

All we need is an easy explanation of the problem, so here it is.

I need to dump some tables of my postgres database and I am scared of getting inconsistent data.The database is verly large and the dump lasts some minutes.
On my research I found a command to dump single tables:

pg_dump --column-inserts -a -t exampleTable -t exampleTable 2> /tmp/myTables.sql

The next problem is that while dumping new data will be inserted in the tables. Is it correct that data which are inserted while dumping are ignored? Especially if I ru the command like the example? Is there anything special to do for dumping?

Or can I really run the pg_dump command and everything is fine? Does anyone have an easy way to test this?

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

No matter how you run pg_dump, it will always use a single REPEATABLE READ READ ONLY transaction to read the data, so it will see a consistent snapshot of the data from the time that the backup started.

So as long as you dump all the data you need with a single pg_dump command, you will be safe from data inconsistencies.

If you want a quote from the documentation:

It makes consistent backups even if the database is being used concurrently.

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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