Migrate from auction_participans to proposed_solutions table (cowprotocol#3766)

# Description
The `auction_participans` table has become obsolete, since the same data
is now stored in the `proposed_solutions`. This PR migrates usage to the
latter table. The migration script will be a part of cowprotocol#3753, since this
is a breaking change, which requires gradual deployment to avoid panics
when running 2 auctions in parallel.

Author: squadgazzz

crates/autopilot/src/database/competition.rs

@@ -4,7 +4,6 @@ use {
     database::{
         Address,
         auction::AuctionId,
-        auction_participants::Participant,
         auction_prices::AuctionPrice,
         byte_array::ByteArray,
         surplus_capturing_jit_order_owners,
@@ -61,21 +60,6 @@ impl super::Postgres {
             .await
             .context("reference_scores::insert")?;
 
-        database::auction_participants::insert(
-            &mut ex,
-            competition
-                .participants
-                .into_iter()
-                .map(|p| Participant {
-                    auction_id: competition.auction_id,
-                    participant: ByteArray(p.0),
-                })
-                .collect::<Vec<_>>()
-                .as_slice(),
-        )
-        .await
-        .context("auction_participants::insert")?;
-
         database::auction_prices::insert(
             &mut ex,
             competition

crates/database/src/auction_participants.rs

@@ -1,3 +1,6 @@
+//! This table is deprecated, since it contains duplicated data in the
+//! `competition_auctions` table. But it can't currently be removed, since the
+//! solver team is still using it.
 use {
     crate::{Address, PgTransaction, auction::AuctionId},
     bigdecimal::BigDecimal,

crates/database/src/auction_prices.rs

@@ -1,6 +1,5 @@
 pub mod app_data;
 pub mod auction;
-pub mod auction_participants;
 pub mod auction_prices;
 pub mod byte_array;
 pub mod ethflow_orders;
@@ -75,7 +74,6 @@ pub const TABLES: &[&str] = &[
 /// The names of potentially big volume tables we use in the db.
 pub const LARGE_TABLES: &[&str] = &[
     "auction_prices",
-    "auction_participants",
     "competition_auctions",
     "fee_policies",
     "orders",

crates/database/src/lib.rs

@@ -188,6 +188,26 @@ pub async fn load_by_id(
     }))
 }
 
+/// Participant of a solver competition for a given auction.
+#[derive(Debug, Clone, PartialEq, sqlx::FromRow)]
+pub struct AuctionParticipant {
+    pub auction_id: AuctionId,
+    pub participant: Address,
+}
+
+pub async fn fetch_auction_participants(
+    ex: &mut PgConnection,
+    auction_id: AuctionId,
+) -> Result<Vec<AuctionParticipant>, sqlx::Error> {
+    const QUERY: &str = r#"
+        SELECT DISTINCT ps.solver AS participant, ps.auction_id
+        FROM proposed_solutions ps
+        WHERE ps.auction_id = $1
+    "#;
+
+    sqlx::query_as(QUERY).bind(auction_id).fetch_all(ex).await
+}
+
 /// Identifies solvers that have consistently failed to settle solutions in
 /// recent N auctions.
 ///
@@ -1213,5 +1233,11 @@ mod tests {
         assert_eq!(solver_competition.reference_scores.len(), 1);
         assert_eq!(solver_competition.solutions.len(), 1);
         assert_eq!(solver_competition.solutions.first().unwrap().uid, 0);
+
+        let auction_participants = fetch_auction_participants(&mut db, auction_id)
+            .await
+            .unwrap();
+        assert_eq!(auction_participants.len(), 1);
+        assert_eq!(auction_participants[0].participant, solutions[0].solver);
     }
 }

crates/database/src/solver_competition_v2.rs

@@ -45,7 +45,7 @@ pub struct AuctionTransaction {
 #[derive(Clone, Debug)]
 pub struct Cip20Data {
     pub txs: Vec<AuctionTransaction>,
-    pub participants: Vec<database::auction_participants::Participant>,
+    pub participants: Vec<database::solver_competition_v2::AuctionParticipant>,
     pub prices: Vec<database::auction_prices::AuctionPrice>,
     pub reference_scores: Vec<database::reference_scores::Score>,
     pub competition: serde_json::Value,
@@ -72,9 +72,10 @@ SELECT * FROM settlements WHERE auction_id = $1";
         .await
         .ok()?;
 
-    let participants = database::auction_participants::fetch(&mut db, auction_id)
-        .await
-        .unwrap();
+    let participants =
+        database::solver_competition_v2::fetch_auction_participants(&mut db, auction_id)
+            .await
+            .unwrap();
     let prices = database::auction_prices::fetch(&mut db, auction_id)
         .await
         .unwrap();

crates/e2e/tests/e2e/database.rs

@@ -23,18 +23,6 @@ Column                | Type        | Nullable | Details
 Indexes:
 - "app\_data\_pkey" PRIMARY KEY, btree (`contract_app_data`)
 
-### auction\_participants
-
-This table is used for [CIP-20](https://snapshot.org/#/cow.eth/proposal/0x2d3f9bd1ea72dca84b03e97dda3efc1f4a42a772c54bd2037e8b62e7d09a491f). It stores which solvers (identified by ethereum address) participated in which auctions (identified by auction id). CIP-20 specifies that "solver teams which consistently provide solutions" get rewarded.
-
-   Column     |  Type  | Nullable | Details
---------------|--------|----------|--------
- auction\_id  | bigint | not null | id of the auction
- participant  | bytea  | not null | solver that submitted a **valid** solution for the auction
-
-Indexes:
-- PRIMARY KEY: btree(`auction_id`, `participant`)
-
 ### auction\_prices
 
 Stores the native price of a token in a given auction. Used for computations related to CIP-20.