[JDBC] [pgjdbc/pgjdbc] f0deab: fix: named statements were used whenfetchSize was...

Branch: refs/heads/master
  Home:   https://github.com/pgjdbc/pgjdbc
  Commit: f0deabf7d87bb5bffeb84e9cd686eeb632aa9687
      https://github.com/pgjdbc/pgjdbc/commit/f0deabf7d87bb5bffeb84e9cd686eeb632aa9687
  Author: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>
  Date:   2017-07-24 (Mon, 24 Jul 2017)

  Changed paths:
    M pgjdbc/src/main/java/org/postgresql/core/v3/QueryExecutorImpl.java
    A pgjdbc/src/test/java/org/postgresql/test/jdbc2/ConcurrentStatementFetch.java
    M pgjdbc/src/test/java/org/postgresql/test/jdbc2/Jdbc2TestSuite.java
    M pgjdbc/src/test/java/org/postgresql/test/jdbc2/PreparedStatementTest.java

  Log Message:
  -----------
  fix: named statements were used when fetchSize was non-zero and prepareThreshold=0 (#870)

Non-zero fetchSize triggers use of named portals (for subsequent fetch requests),
however named portals does not require to use named statements.

As per PostgreSQL documentation, named portals are automatically closed as transaction completes, so named portals
shouldplay well with transaction-based poolers. 

fixes #869