How to debug "could not receive data from client: Connection reset by peer"

I'm getting it in 2017 with 9.4, I have no text fields, don't know what a PDO is. My select statement is about 50 bytes long, I'm trying to fetch an int4 and a double precision. I suspect the error message can mean multiple things.

I've since found https://dba.stackexchange.com/questions/142350/postgres-could-not-receive-data-from-client-connection-reset-by-peer which indicates it could be a problem with the client configuration. My client is libpg and PQconnectdb() is giving me a CONNECTION_OK return. It works at least partly.

I know this is an older post, but I just found it because I had the same error today in my postgres logs. I narrowed it down to a PDO select statement. I'm using Zend Framework 1.10.3 on Ubuntu Precise.

The following pdo statement generated an error if $opinion is a long text string. The column opinion is type Text in my postgres table. The query succeeds if $opinion is under a certain number of characters. 1000 characters works fine. 2000 characters fails with "could not receive data from client: Connection reset by peer".

  $select = $this->db->select()
           ->from( 'datauserstopics' )
           ->where("opinion = ?",trim($opinion))
           ->where("datatopicsid = ?",trim($tid))
           ->where("datausersid= ?",$datausersid);

  $stmt = $this->db->query($select);

I circumvented the problem by using: ->where("substr(opinion,1,100) = ?",trim(substr($opinion,1,100)))

This is not a perfect solution, but for my purposes, the select statement using substr() suffices.

Note that I have no problem inserting long strings into the same table/column. The disconnect problem only appears for me on the PDO select with relatively long text strings.