Address review comments

Author: DOBEN

backend-rust/CHANGELOG.md

@@ -4,17 +4,12 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
-Database schema version: 3
-
-### Added
-
-- Add database schema version 3 with index over accounts that delegate stake to a given baker pool.
-- Add `delegator_count`, `delegated_stake`, `total_stake`, and `total_stake_percentage` to baker pool query.
-
 Database schema version: 2
 
 ### Added
 
+- Add `delegator_count`, `delegated_stake`, `total_stake`, and `total_stake_percentage` to baker pool query.
+- Add index over accounts that delegate stake to a given baker pool.
 - Add `database_schema_version` and `api_supported_database_schema_version` to `versions` endpoint.
 - Add database schema version 2 with index over blocks with no `cumulative_finalization_time`, to improve indexing performance.
 

backend-rust/src/graphql_api/baker.rs

@@ -3,7 +3,7 @@ use super::{
     ApiResult, ConnectionQuery,
 };
 use crate::{
-    scalar_types::{Amount, BakerId, DateTime, Decimal, MetadataUrl, UnsignedLong},
+    scalar_types::{Amount, BakerId, DateTime, Decimal, MetadataUrl},
     transaction_event::{baker::BakerPoolOpenStatus, Event},
     transaction_reject::TransactionRejectReason,
     transaction_type::{
@@ -131,9 +131,8 @@ impl Baker {
 
         let total_stake: i64 =
             sqlx::query_scalar!("SELECT total_staked FROM blocks ORDER BY height DESC LIMIT 1")
-                .fetch_optional(pool)
-                .await?
-                .ok_or(ApiError::NotFound)?;
+                .fetch_one(pool)
+                .await?;
 
         let row = sqlx::query!(
             "
@@ -156,9 +155,11 @@ impl Baker {
 
         // Division by 0 is not possible because `total_staked` is always a positive
         // number.
-        let total_stake_percentage = (total_pool_stake as f64 * 100.0 / total_stake as f64)
-            .try_into()
-            .map_err(|e: anyhow::Error| ApiError::InternalError(e.to_string()))?;
+        let total_stake_percentage = (rust_decimal::Decimal::from(total_pool_stake)
+            * rust_decimal::Decimal::from(100))
+        .checked_div(rust_decimal::Decimal::from(total_stake))
+        .ok_or_else(|| ApiError::InternalError("Division by zero or overflow".to_string()))?
+        .into();
 
         let out = BakerState::ActiveBakerState(ActiveBakerState {
             staked_amount:    Amount::try_from(self.staked)?,
@@ -172,8 +173,8 @@ impl Baker {
                 },
                 metadata_url: self.metadata_url.as_deref(),
                 total_stake_percentage,
-                total_stake: UnsignedLong(total_pool_stake.try_into()?),
-                delegated_stake: UnsignedLong(delegated_stake.try_into()?),
+                total_stake: total_pool_stake.try_into()?,
+                delegated_stake: delegated_stake.try_into()?,
                 delegator_count: row.delegator_count.unwrap_or(0),
             },
             pending_change:   None, // This is not used starting from P7.

backend-rust/src/migrations.rs

@@ -171,8 +171,6 @@ pub enum SchemaVersion {
          performance."
     )]
     IndexBlocksWithNoCumulativeFinTime,
-    #[display("0003:Adds index over accounts that delegate stake to a given baker pool.")]
-    IndexAccountsWithDelegatedStakeToBakerId,
 }
 impl SchemaVersion {
     /// The minimum supported database schema version for the API.
@@ -198,7 +196,6 @@ impl SchemaVersion {
             SchemaVersion::Empty => false,
             SchemaVersion::InitialFirstHalf => false,
             SchemaVersion::IndexBlocksWithNoCumulativeFinTime => false,
-            SchemaVersion::IndexAccountsWithDelegatedStakeToBakerId => false,
         }
     }
 
@@ -222,15 +219,7 @@ impl SchemaVersion {
                     .await?;
                 SchemaVersion::IndexBlocksWithNoCumulativeFinTime
             }
-            SchemaVersion::IndexBlocksWithNoCumulativeFinTime => {
-                tx.as_mut()
-                    .execute(sqlx::raw_sql(include_str!(
-                        "./migrations/m0003-index-accounts-with-delegated-stake-to-baker-id.sql"
-                    )))
-                    .await?;
-                SchemaVersion::IndexAccountsWithDelegatedStakeToBakerId
-            }
-            SchemaVersion::IndexAccountsWithDelegatedStakeToBakerId => unimplemented!(
+            SchemaVersion::IndexBlocksWithNoCumulativeFinTime => unimplemented!(
                 "No migration implemented for database schema version {}",
                 self.as_i64()
             ),

backend-rust/src/migrations/m0002-block-cumulative-fin-time-index.sql

@@ -3,3 +3,6 @@
 CREATE INDEX blocks_height_null_cumulative_finalization_time ON blocks (height)
     WHERE blocks.cumulative_finalization_time IS NULL
     AND blocks.finalization_time IS NOT NULL;
+
+-- Important for quickly calculating the delegated stake to a baker pool.
+CREATE INDEX delegated_target_baker_id_index ON accounts(delegated_target_baker_id);