From b6579e73502fe4c881b894980a4acc506e33618c Mon Sep 17 00:00:00 2001
From: Tacio Medeiros <tacio@fedi.xyz>
Date: Mon, 16 Sep 2024 15:22:57 -0300
Subject: [PATCH] refactor: updated session_times view

---
 fmo_server/schema/v5.sql              | 84 +++++++++++++++++++++++++++
 fmo_server/src/federation/observer.rs |  4 ++
 2 files changed, 88 insertions(+)
 create mode 100644 fmo_server/schema/v5.sql

diff --git a/fmo_server/schema/v5.sql b/fmo_server/schema/v5.sql
new file mode 100644
index 0000000..9811ede
--- /dev/null
+++ b/fmo_server/schema/v5.sql
@@ -0,0 +1,84 @@
+-- Create the update session_times view
+BEGIN;
+INSERT INTO schema_version (version)
+VALUES (5);
+
+DROP MATERIALIZED VIEW IF EXISTS session_times;
+
+CREATE MATERIALIZED VIEW session_times AS
+WITH proposer_votes AS (
+    SELECT
+        federation_id,
+        session_index,
+        proposer,
+        MAX(height_vote) AS proposer_height
+    FROM block_height_votes
+    GROUP BY federation_id, session_index, proposer
+),
+
+session_proposer_heights AS (
+    SELECT
+        federation_id,
+        session_index,
+        proposer_height,
+        COUNT(*) AS vote_cnt
+    FROM proposer_votes
+    GROUP BY federation_id, session_index, proposer_height
+),
+
+session_heights AS (
+    SELECT
+        federation_id,
+        session_index,
+        proposer_height AS block_height,
+        vote_cnt,
+        ROW_NUMBER()
+            OVER (
+                PARTITION BY federation_id, session_index ORDER BY vote_cnt DESC
+            )
+        AS rn
+    FROM session_proposer_heights
+),
+
+session_times AS (
+    SELECT
+        sh.federation_id,
+        sh.session_index,
+        sh.block_height,
+        bt.timestamp,
+        sh.vote_cnt
+    FROM session_heights AS sh
+    LEFT JOIN
+        block_times AS bt
+        ON sh.block_height = bt.block_height
+    WHERE sh.rn = 1
+)
+
+SELECT
+    s.federation_id,
+    s.session_index,
+    MAX(st.timestamp)
+        OVER (
+            PARTITION BY s.federation_id
+            ORDER BY
+                s.session_index
+            ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+        )
+    AS estimated_session_timestamp
+FROM sessions AS s
+LEFT JOIN
+    session_times AS st
+    ON s.federation_id = st.federation_id AND s.session_index = st.session_index
+ORDER BY s.federation_id, s.session_index;
+
+CREATE INDEX session_times_federation_id_idx ON session_times (federation_id);
+
+CREATE UNIQUE INDEX session_times_federation_id_session_index_idx ON session_times (
+    federation_id, session_index
+);
+
+CREATE INDEX session_times_federation_id_estimated_session_timestamp_idx ON session_times (
+    federation_id, estimated_session_timestamp
+);
+
+COMMIT;
diff --git a/fmo_server/src/federation/observer.rs b/fmo_server/src/federation/observer.rs
index 8352fac..899d556 100644
--- a/fmo_server/src/federation/observer.rs
+++ b/fmo_server/src/federation/observer.rs
@@ -164,6 +164,10 @@ impl FederationObserver {
                 4,
                 include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/schema/v4.sql")),
             ),
+            (
+                5,
+                include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/schema/v5.sql")),
+            ),
         ];
 
         for (version, migration) in migration_map.iter() {