Add Debug bound on ToSql and log params during stmt execution

src/lib.rs

@@ -65,7 +65,7 @@ use std::borrow::{ToOwned, Cow};
 use std::cell::{Cell, RefCell};
 use std::collections::{VecDeque, HashMap};
 use std::fmt;
-use std::iter::{IntoIterator, RandomAccessIterator};
+use std::iter::IntoIterator;
 use std::io::{self, BufStream};
 use std::io::prelude::*;
 use std::mem;
@@ -1353,7 +1353,7 @@ impl<'conn> Statement<'conn> {
                 "expected {} parameters but got {}",
                 self.param_types.len(),
                 params.len());
-        debug!("executing statement {}", self.name);
+        debug!("executing statement {} with parameters: {:?}", self.name, params);
         let mut values = vec![];
         for (param, ty) in params.iter().zip(self.param_types.iter()) {
             let mut buf = vec![];
@@ -2032,7 +2032,7 @@ impl<'a> CopyInStatement<'a> {
             where I: Iterator<Item=J>, J: StreamIterator {
         let mut conn = self.conn.conn.borrow_mut();
 
-        debug!("executing statement {}", self.name);
+        debug!("executing COPY IN statement {}", self.name);
         try!(conn.write_messages(&[
             Bind {
                 portal: "",

src/types/mod.rs

@@ -605,7 +605,7 @@ pub enum IsNull {
 }
 
 /// A trait for types that can be converted into Postgres values.
-pub trait ToSql {
+pub trait ToSql: fmt::Debug {
     /// Converts the value of `self` into the binary format of the specified
     /// Postgres `Type`, writing it to `out`.
     ///

src/types/slice.rs

@@ -24,6 +24,7 @@ use types::IsNull;
 /// }
 /// # Ok(()) }
 /// ```
+#[derive(Debug)]
 pub struct Slice<'a, T: 'a + ToSql>(pub &'a [T]);
 
 impl<'a, T: 'a + ToSql> ToSql for Slice<'a, T> {