It seems that PostgreSQL transactional pool mode is not supported yet.

## Describe the bug

Problem:
Using pgbouncer's transaction mode (port 6543) instead of session mode causes critical issues:

Parameter Binding Error

Error message "bind message supplies 4 parameters, but prepared statement requires 1" typically occurs when pgbouncer creates new connections for each query.

This breaks XORM's parameter binding mechanism, causing a mismatch in the number of parameters expected by the query statement. (It seems session states are being used and lost.)

Example error:

> bind message supplies 4 parameters, but prepared statement requires 1

For the Query: "SELECT \"id\", \"created_at\", \"updated_at\", \"user_id\", \"invite_user_id\", \"last_edit_user_id\", \"title\", \"original_text\", \"parsed_text\", \"pin\", \"show\", \"status\", \"view_count\", \"unique_view_count\", \"vote_count\", \"answer_count\", \"hot_score\", \"collection_count\", \"follow_count\", \"accepted_answer_id\", \"last_answer_id\", \"post_update_time\", \"revision_id\" FROM \"question\" WHERE \"question\".\"status\" IN ($1,$2) AND (question.show = $3) AND (question.created_at > $4) ORDER BY question.pin desc,question.hot_score DESC LIMIT 6"

### To Reproduce

Steps to reproduce the behavior:

1. With a brand new system being set up with an transaction mode postgresdb, you can get the error everytime.

### Expected behavior

5xx error report

Reproduce the failure with PostgreSQL behind pgbouncer in transaction mode on port 6543, using the query and parameter-binding error from the report. Trace how the connection and prepared-statement state are handled; done means the query no longer fails with a parameter-count mismatch in transaction mode.

Written by the indexing model from the issue text.