perf: drop the legacy audit index and per-table limit from this PR

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

backend/ee-repo-ref.txt

@@ -1 +1 @@
-f105ffea9daca8d5c18ba6e0d604f7eb6df4cb58
+bc3ef08c8e4233508c023e6ee847a3cd0b8be43b

backend/migrations/20260918173412_audit_partitioned_workspace_operation_index.down.sql

@@ -1,2 +1 @@
 DROP INDEX IF EXISTS ix_audit_partitioned_workspace_operation;
-DROP INDEX IF EXISTS ix_audit_workspace_operation;

backend/migrations/20260918173412_audit_partitioned_workspace_operation_index.up.sql

@@ -1,8 +1,6 @@
--- The backend builds these with CREATE INDEX CONCURRENTLY instead (per partition for
--- audit_partitioned), see create_audit_operation_index_concurrently in windmill-api/src/db.rs.
+-- The backend builds this per partition with CREATE INDEX CONCURRENTLY instead,
+-- see create_audit_operation_index_concurrently in windmill-api/src/db.rs.
 -- id matches list_audit's order and before_id cursor. timestamp trails it so a
 -- time window is checked in the index rather than on every row it reads.
-CREATE INDEX IF NOT EXISTS ix_audit_workspace_operation
-    ON audit (workspace_id, operation, id DESC, "timestamp");
 CREATE INDEX IF NOT EXISTS ix_audit_partitioned_workspace_operation
     ON audit_partitioned (workspace_id, operation, id DESC, "timestamp");

backend/tests/list_audit.rs

@@ -1,60 +0,0 @@
-#![cfg(feature = "private")]
-
-use sqlx::{Pool, Postgres};
-
-use windmill_test_utils::*;
-
-/// Each table is limited on its own before the union is paginated, so a page past the first must
-/// still see every row ranked ahead of it in both tables.
-#[sqlx::test(fixtures("base"))]
-async fn test_list_audit_paginates_across_legacy_and_partitioned(
-    db: Pool<Postgres>,
-) -> anyhow::Result<()> {
-    initialize_tracing().await;
-
-    let server = ApiServer::start(db.clone()).await?;
-    let port = server.addr.port();
-    let client = windmill_api_client::create_client(
-        &format!("http://localhost:{port}"),
-        "SECRET_TOKEN".to_string(),
-    );
-
-    for (table, id) in [
-        ("audit", 1),
-        ("audit", 2),
-        ("audit", 3),
-        ("audit_partitioned", 101),
-        ("audit_partitioned", 102),
-        ("audit_partitioned", 103),
-    ] {
-        sqlx::query(&format!(
-            "INSERT INTO {table} (workspace_id, id, username, operation, action_kind)
-             VALUES ('test-workspace', $1, 'test-user', 'test.op', 'execute')"
-        ))
-        .bind(id as i64)
-        .execute(&db)
-        .await?;
-    }
-
-    let mut ids = vec![];
-    for page in 1..=4 {
-        let response = client
-            .client()
-            .get(format!(
-                "{}/w/test-workspace/audit/list?operation=test.op&per_page=2&page={page}",
-                client.baseurl()
-            ))
-            .send()
-            .await?;
-        assert!(
-            response.status().is_success(),
-            "page {page}: {}",
-            response.text().await?
-        );
-        let rows = response.json::<Vec<serde_json::Value>>().await?;
-        ids.extend(rows.iter().map(|r| r["id"].as_i64().unwrap()));
-    }
-    assert_eq!(ids, vec![103, 102, 101, 3, 2, 1]);
-
-    Ok(())
-}

backend/windmill-api/src/db.rs

@@ -40,27 +40,6 @@ const AUDIT_OPERATION_INDEX_KEY: &str = r#"(workspace_id, operation, id DESC, "t
 async fn create_audit_operation_index_concurrently(
     conn: &mut PgConnection,
 ) -> Result<(), MigrateError> {
-    // list_audit reads the legacy table too, which holds up to a retention period of rows
-    // written before partitioning.
-    let legacy_valid: Option<bool> = sqlx::query_scalar(
-        "SELECT indisvalid FROM pg_index
-         WHERE indexrelid = to_regclass('ix_audit_workspace_operation')",
-    )
-    .fetch_optional(&mut *conn)
-    .await?;
-    if legacy_valid != Some(true) {
-        conn.execute("DROP INDEX CONCURRENTLY IF EXISTS ix_audit_workspace_operation")
-            .await?;
-        conn.execute(
-            format!(
-                "CREATE INDEX CONCURRENTLY ix_audit_workspace_operation \
-                 ON audit {AUDIT_OPERATION_INDEX_KEY}"
-            )
-            .as_str(),
-        )
-        .await?;
-    }
-
     conn.execute(
         format!(
             "CREATE INDEX IF NOT EXISTS ix_audit_partitioned_workspace_operation \