PGAdmin: Not connected to the server or the connection to the server has been closed

问题

i got this problem with postgreSQL, when i do a simple query of anything (CRUD), sometimes it works and almost always shows this message:

Not connected to the server or the connection to the server has been closed.

I don't know how to solve it and it started to irritate me, anyone know how to fix it?

UPDATE 1

I have been searching and it seems the pgadmin4 the problem (it seems because it's not 100% developed yet), i have been using pgadmin3 and that error doesn't show up.

回答1:

The reason this happened for me was a syntax error in the query. Check your syntax and try again, maybe this suffices

回答2:

This issue has been fixed.

Upgrade to pgAdmin4 version 2.0. https://www.pgadmin.org/download/

回答3:

I have similiar problem before, im using postgre 9.6.1-1 I can do select without condition (ex: select * from foodtable) and i can do insert too.. But if i do select or edit or delete using a condition (ex: select * from foodtable where taste='sweet') the output is like your

Not connected to the server or the connection to the server has been closed.

I try reinstall (After uninstall delete all leftover data) and delete C:\Users\yourUserName\AppData\Roaming\pgAdmin (delete all data inside pgAdmin Folder) And its works

Update-> Your table name and field name must lowercase

回答4:

solution is:

select the database where you lost the connection.

then on the right hand side select SQL

For example in the picture (shopdb) is the db where I lost the connection to.

After that PgAdmin will ask you if you would like to reconnect to this database... click ok

you will notice a message retreiving data from the server

回答5:

Can you run & provide output of these sql queries from pgAdmin4?

1) SHOW SERVER_ENCODING;
2) SHOW CLIENT_ENCODING;

And what is the encoding set for your current database connection on which you are trying to run query (Right click on your database, click on Properties > Definition Tab > Check Encoding, Collation & Character type) ?

I'm suspecting you are facing issues due to encoding.

回答6:

Change the versión of pgAdmin, use pgAdmin 3, its a problem frequently between Windows 10 and pgAdmin4.

回答7:

just change the column name and run the query , it worked for me.

my column name was timestamp, it conflicted with datatype so i changed timestamp by _timestamp

回答8:

I solved this. I pressed F7 or Explain in drop-down list near the Execute button. Then I saw where exactly the trouble was. pgAdmin4 didn`t like the name of my column. Then I went to problem column and renamed it.

回答9:

I have same problem but i can create DB and table successful and my version is: window10 pro x64 9.5 (X86)

pgAdmin4

after i change to 9.4 (X86)+ pgAdmin3 is no more error.. and the table i create by 9.5 can be use(insert data) in pgAdmin3

回答10:

I was getting this error when running a long series of queries in a transaction. Then when I ran them separately, it didn't loose the connection. Still no idea why it actually happens...

回答11:

Juuuuust in case someone googled this post like i did. If you have JSON column AND you want to see ANY result in pgAdmin, cast JSON into VARCHAR like

SELECT id, metadata::VARCHAR FROM data_table;

It doesn't matter if content is NULL or not, JSON doesn't work. Maybe there are other types or values that can't be parsed by pgAdmin as well.

Note: you can still insert values and recieve them after cast, so the problem is on JS side (put one more coin into your "Hate JS" jar).

回答12:

We have just experienced this on a standalone windows machine.

After reinstalling things and looking everywhere (logs, running psql in shell - all was good) then we found out that it was an older firefox that was the culprit.

So - please ensure that your browser is up to date :-)