fix(pindexer): correct encoding of Amount into Postgres (#4772)

I tried and tried to actually use Numeric directly in a smart way,
instead the hack is to just cast text into it in the SQL query. Oh well.

## Checklist before requesting a review

- [x] If this code contains consensus-breaking changes, I have added the
"consensus-breaking" label. Otherwise, I declare my belief that there
are not consensus-breaking changes, for the following reason:

  > pindexer bug fix

crates/bin/pindexer/Cargo.toml

@@ -24,5 +24,5 @@ penumbra-asset = {workspace = true, default-features = false}
 penumbra-proto = {workspace = true, default-features = false}
 tokio = {workspace = true, features = ["full"]}
 serde_json = {workspace = true}
-sqlx = { workspace = true, features = ["bigdecimal", "chrono", "postgres"] }
+sqlx = { workspace = true, features = ["chrono", "postgres"] }
 tracing = {workspace = true}

crates/bin/pindexer/src/dex/mod.rs

@@ -56,11 +56,11 @@ impl Event {
                 sqlx::query(
                     r#"
                 INSERT INTO dex_value_circuit_breaker_change
-                VALUES ($1, $2);
+                VALUES ($1, CAST($2 AS Amount));
                 "#,
                 )
                 .bind(Sql::from(*asset_id))
-                .bind(Sql::from(amount))
+                .bind(amount.to_string())
                 .execute(dbtx.as_mut())
                 .await?;
                 Ok(())
@@ -78,11 +78,11 @@ impl Event {
                 sqlx::query(
                     r#"
                 INSERT INTO dex_value_circuit_breaker_change
-                VALUES ($1, -$2);
+                VALUES ($1, -(CAST($2 AS Amount)));
                 "#,
                 )
                 .bind(Sql::from(*asset_id))
-                .bind(Sql::from(amount))
+                .bind(amount.to_string())
                 .execute(dbtx.as_mut())
                 .await?;
                 Ok(())
@@ -94,10 +94,10 @@ impl Event {
                     let mut step_start = None;
                     let mut step_end = None;
                     for step in trace {
-                        let (id,): (i64,) = sqlx::query_as(
-                            r#"INSERT INTO trace_step VALUES (DEFAULT, ($1, $2)) RETURNING id;"#,
+                        let (id,): (i32,) = sqlx::query_as(
+                            r#"INSERT INTO trace_step VALUES (DEFAULT, (CAST($1 AS Amount), $2)) RETURNING id;"#,
                         )
-                        .bind(Sql::from(step.amount))
+                        .bind(step.amount.to_string())
                         .bind(Sql::from(step.asset_id))
                         .fetch_one(dbtx.as_mut())
                         .await?;
@@ -106,7 +106,7 @@ impl Event {
                         }
                         step_end = Some(id);
                     }
-                    let (id,): (i64,) = sqlx::query_as(
+                    let (id,): (i32,) = sqlx::query_as(
                         r#"INSERT INTO trace VALUES (DEFAULT, $1, $2) RETURNING id;"#,
                     )
                     .bind(step_start)
@@ -118,11 +118,11 @@ impl Event {
                     }
                     trace_end = Some(id);
                 }
-                sqlx::query(r#"INSERT INTO arb VALUES ($1, ($2, $3), ($4, $5), $6, $7);"#)
+                sqlx::query(r#"INSERT INTO arb VALUES ($1, (CAST($2 AS Amount), $3), (CAST($4 AS AMOUNT), $5), $6, $7);"#)
                     .bind(i64::try_from(*height)?)
-                    .bind(Sql::from(execution.input.amount))
+                    .bind(execution.input.amount.to_string())
                     .bind(Sql::from(execution.input.asset_id))
-                    .bind(Sql::from(execution.output.amount))
+                    .bind(execution.output.amount.to_string())
                     .bind(Sql::from(execution.output.asset_id))
                     .bind(trace_start)
                     .bind(trace_end)

crates/bin/pindexer/src/sql.rs

@@ -1,10 +1,7 @@
 use std::error::Error;
 
-use anyhow::anyhow;
-use num_bigint::{BigInt, Sign};
 use penumbra_asset::asset::Id as AssetId;
-use penumbra_num::Amount;
-use sqlx::{types::BigDecimal, Decode, Encode, Postgres, Type};
+use sqlx::{Decode, Encode, Postgres, Type};
 
 /// An extension trait to make it easier to implement serialization for existing Penumbra types.
 ///
@@ -74,33 +71,6 @@ where
     }
 }
 
-impl SqlExt for Amount {
-    type SqlT = BigDecimal;
-
-    fn to_sql_type(&self) -> Self::SqlT {
-        BigDecimal::from(BigInt::from_bytes_le(
-            Sign::Plus,
-            self.to_le_bytes().as_slice(),
-        ))
-    }
-
-    fn from_sql_type(value: Self::SqlT) -> anyhow::Result<Self> {
-        if !value.is_integer() {
-            return Err(anyhow!("database value is not an integer").into());
-        }
-        let big_int = value.as_bigint_and_exponent().0;
-        // Get the bytes only from a positive BigInt
-        let bytes = match big_int.to_bytes_le() {
-            (Sign::Plus | Sign::NoSign, bytes) => bytes,
-            (Sign::Minus, bytes) => bytes,
-        };
-        let bytes: [u8; 16] = bytes
-            .try_into()
-            .map_err(|_| anyhow!("failed to convert slice to 16 bytes"))?;
-        Ok(Amount::from_le_bytes(bytes))
-    }
-}
-
 impl SqlExt for AssetId {
     type SqlT = [u8; 32];