Re: the same time value return different values，is it a problem

On Wed, 13 Sept 2023 at 10:17, Tom Lane <tgl@sss.pgh.pa.us> wrote:

姜梦洋 <minesunny@icloud.com> writes:
>       I find the time type accuracy of the database. Using PreparedStatement, the accuracy found out for the sixth time is different from the first five times. This number is exactly the same as the threshold of the PreparedStatement. I can understand that the database can optimize PreparedStatements and reduce repeated parsing and other unnecessary operations. but I don’t quite understand how such processing will affect the execution results(Or maybe I don’t have a deep understanding of PreparedStatement.).

What is the difference and the type of the column? I'm not about to open a zip file.

 

If you're using JDBC, this is probably the same effect discussed at

https://www.postgresql.org/message-id/flat/CAKyg5Sj%3D85niw8%3DZhX-quHaCQTPhG40REi1s%2BHYF6Snz4Dfi7Q%40mail.gmail.com

It's got something to do with retrieving the query results in binary
mode instead of text.  The query result at the server is the same,
but the JDBC driver is rendering it differently.

rendering is not quite right. The parsing tends to be slightly different in text vs binary.