ha executor

crates/common/src/models.rs

@@ -1412,7 +1412,7 @@ pub mod artifact {
         pub content_type: Option<String>,
         /// Size of the latest version's content in bytes
         pub size_bytes: Option<i64>,
-        /// Execution that produced this artifact (no FK — execution is a hypertable)
+        /// Execution that produced this artifact (no FK by design)
         pub execution: Option<Id>,
         /// Structured JSONB data for progress artifacts or metadata
         pub data: Option<serde_json::Value>,

crates/common/src/repositories/analytics.rs

@@ -80,7 +80,7 @@ pub struct EnforcementVolumeBucket {
     pub enforcement_count: i64,
 }
 
-/// A single hourly bucket of execution volume (from execution hypertable directly).
+/// A single hourly bucket of execution volume (from the execution table directly).
 #[derive(Debug, Clone, Serialize, FromRow)]
 pub struct ExecutionVolumeBucket {
     /// Start of the 1-hour bucket
@@ -468,7 +468,7 @@ impl AnalyticsRepository {
     }
 
     // =======================================================================
-    // Execution volume (from execution hypertable directly)
+    // Execution volume (from the execution table directly)
     // =======================================================================
 
     /// Query the `execution_volume_hourly` continuous aggregate for execution

crates/common/src/repositories/event.rs

@@ -65,6 +65,12 @@ pub struct EnforcementSearchResult {
     pub total: u64,
 }
 
+#[derive(Debug, Clone)]
+pub struct EnforcementCreateOrGetResult {
+    pub enforcement: Enforcement,
+    pub created: bool,
+}
+
 /// Repository for Event operations
 pub struct EventRepository;
 
@@ -493,11 +499,7 @@ impl EnforcementRepository {
         Ok(enforcement)
     }
 
-    /// Update an enforcement using the loaded row's hypertable keys.
-    ///
-    /// This avoids wide scans across compressed chunks by including both the
-    /// partitioning column (`created`) and compression segment key (`rule_ref`)
-    /// in the locator.
+    /// Update an enforcement using the loaded row's primary key.
     pub async fn update_loaded<'e, E>(
         executor: E,
         enforcement: &Enforcement,
@@ -510,19 +512,73 @@ impl EnforcementRepository {
             return Ok(enforcement.clone());
         }
 
-        let rule_ref = enforcement.rule_ref.clone();
-
         Self::update_with_locator(executor, input, |query| {
             query.push(" WHERE id = ");
             query.push_bind(enforcement.id);
-            query.push(" AND created = ");
-            query.push_bind(enforcement.created);
-            query.push(" AND rule_ref = ");
-            query.push_bind(rule_ref);
         })
         .await
     }
 
+    pub async fn update_loaded_if_status<'e, E>(
+        executor: E,
+        enforcement: &Enforcement,
+        expected_status: EnforcementStatus,
+        input: UpdateEnforcementInput,
+    ) -> Result<Option<Enforcement>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        if input.status.is_none() && input.payload.is_none() && input.resolved_at.is_none() {
+            return Ok(Some(enforcement.clone()));
+        }
+
+        let mut query = QueryBuilder::new("UPDATE enforcement SET ");
+        let mut has_updates = false;
+
+        if let Some(status) = input.status {
+            query.push("status = ");
+            query.push_bind(status);
+            has_updates = true;
+        }
+
+        if let Some(payload) = &input.payload {
+            if has_updates {
+                query.push(", ");
+            }
+            query.push("payload = ");
+            query.push_bind(payload);
+            has_updates = true;
+        }
+
+        if let Some(resolved_at) = input.resolved_at {
+            if has_updates {
+                query.push(", ");
+            }
+            query.push("resolved_at = ");
+            query.push_bind(resolved_at);
+            has_updates = true;
+        }
+
+        if !has_updates {
+            return Ok(Some(enforcement.clone()));
+        }
+
+        query.push(" WHERE id = ");
+        query.push_bind(enforcement.id);
+        query.push(" AND status = ");
+        query.push_bind(expected_status);
+        query.push(
+            " RETURNING id, rule, rule_ref, trigger_ref, config, event, status, payload, \
+             condition, conditions, created, resolved_at",
+        );
+
+        query
+            .build_query_as::<Enforcement>()
+            .fetch_optional(executor)
+            .await
+            .map_err(Into::into)
+    }
+
     /// Find enforcements by rule ID
     pub async fn find_by_rule<'e, E>(executor: E, rule_id: Id) -> Result<Vec<Enforcement>>
     where
@@ -589,6 +645,90 @@ impl EnforcementRepository {
         Ok(enforcements)
     }
 
+    pub async fn find_by_rule_and_event<'e, E>(
+        executor: E,
+        rule_id: Id,
+        event_id: Id,
+    ) -> Result<Option<Enforcement>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        sqlx::query_as::<_, Enforcement>(
+            r#"
+            SELECT id, rule, rule_ref, trigger_ref, config, event, status, payload,
+                   condition, conditions, created, resolved_at
+            FROM enforcement
+            WHERE rule = $1 AND event = $2
+            LIMIT 1
+            "#,
+        )
+        .bind(rule_id)
+        .bind(event_id)
+        .fetch_optional(executor)
+        .await
+        .map_err(Into::into)
+    }
+
+    pub async fn create_or_get_by_rule_event<'e, E>(
+        executor: E,
+        input: CreateEnforcementInput,
+    ) -> Result<EnforcementCreateOrGetResult>
+    where
+        E: Executor<'e, Database = Postgres> + Copy + 'e,
+    {
+        let (Some(rule_id), Some(event_id)) = (input.rule, input.event) else {
+            let enforcement = Self::create(executor, input).await?;
+            return Ok(EnforcementCreateOrGetResult {
+                enforcement,
+                created: true,
+            });
+        };
+
+        let inserted = sqlx::query_as::<_, Enforcement>(
+            r#"
+            INSERT INTO enforcement (rule, rule_ref, trigger_ref, config, event, status,
+                                     payload, condition, conditions)
+            VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+            ON CONFLICT (rule, event) WHERE rule IS NOT NULL AND event IS NOT NULL DO NOTHING
+            RETURNING id, rule, rule_ref, trigger_ref, config, event, status, payload,
+                      condition, conditions, created, resolved_at
+            "#,
+        )
+        .bind(input.rule)
+        .bind(&input.rule_ref)
+        .bind(&input.trigger_ref)
+        .bind(&input.config)
+        .bind(input.event)
+        .bind(input.status)
+        .bind(&input.payload)
+        .bind(input.condition)
+        .bind(&input.conditions)
+        .fetch_optional(executor)
+        .await?;
+
+        if let Some(enforcement) = inserted {
+            return Ok(EnforcementCreateOrGetResult {
+                enforcement,
+                created: true,
+            });
+        }
+
+        let enforcement = Self::find_by_rule_and_event(executor, rule_id, event_id)
+            .await?
+            .ok_or_else(|| {
+                anyhow::anyhow!(
+                    "enforcement for rule {} and event {} disappeared after dedupe conflict",
+                    rule_id,
+                    event_id
+                )
+            })?;
+
+        Ok(EnforcementCreateOrGetResult {
+            enforcement,
+            created: false,
+        })
+    }
+
     /// Search enforcements with all filters pushed into SQL.
     ///
     /// All filter fields are combinable (AND). Pagination is server-side.

crates/common/src/repositories/execution.rs

@@ -4,7 +4,8 @@ use chrono::{DateTime, Utc};
 
 use crate::models::{enums::ExecutionStatus, execution::*, Id, JsonDict};
 use crate::Result;
-use sqlx::{Executor, Postgres, QueryBuilder};
+use sqlx::{Executor, PgConnection, PgPool, Postgres, QueryBuilder};
+use tokio::time::{sleep, Duration};
 
 use super::{Create, Delete, FindById, List, Repository, Update};
 
@@ -47,6 +48,12 @@ pub struct WorkflowTaskExecutionCreateOrGetResult {
     pub created: bool,
 }
 
+#[derive(Debug, Clone)]
+pub struct EnforcementExecutionCreateOrGetResult {
+    pub execution: Execution,
+    pub created: bool,
+}
+
 /// An execution row with optional `rule_ref` / `trigger_ref` populated from
 /// the joined `enforcement` table. This avoids a separate in-memory lookup.
 #[derive(Debug, Clone, sqlx::FromRow)]
@@ -215,32 +222,392 @@ impl Update for ExecutionRepository {
 }
 
 impl ExecutionRepository {
-    pub async fn create_workflow_task_if_absent<'e, E>(
+    pub async fn find_top_level_by_enforcement<'e, E>(
         executor: E,
+        enforcement_id: Id,
+    ) -> Result<Option<Execution>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        let sql = format!(
+            "SELECT {SELECT_COLUMNS} \
+             FROM execution \
+             WHERE enforcement = $1
+               AND parent IS NULL
+               AND (config IS NULL OR NOT (config ? 'retry_of')) \
+             ORDER BY created ASC \
+             LIMIT 1"
+        );
+
+        sqlx::query_as::<_, Execution>(&sql)
+            .bind(enforcement_id)
+            .fetch_optional(executor)
+            .await
+            .map_err(Into::into)
+    }
+
+    pub async fn create_top_level_for_enforcement_if_absent<'e, E>(
+        executor: E,
+        input: CreateExecutionInput,
+        enforcement_id: Id,
+    ) -> Result<EnforcementExecutionCreateOrGetResult>
+    where
+        E: Executor<'e, Database = Postgres> + Copy + 'e,
+    {
+        let inserted = sqlx::query_as::<_, Execution>(&format!(
+            "INSERT INTO execution \
+             (action, action_ref, config, env_vars, parent, enforcement, executor, worker, status, result, workflow_task) \
+             VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11) \
+             ON CONFLICT (enforcement)
+             WHERE enforcement IS NOT NULL
+               AND parent IS NULL
+               AND (config IS NULL OR NOT (config ? 'retry_of'))
+             DO NOTHING \
+             RETURNING {SELECT_COLUMNS}"
+        ))
+        .bind(input.action)
+        .bind(&input.action_ref)
+        .bind(&input.config)
+        .bind(&input.env_vars)
+        .bind(input.parent)
+        .bind(input.enforcement)
+        .bind(input.executor)
+        .bind(input.worker)
+        .bind(input.status)
+        .bind(&input.result)
+        .bind(sqlx::types::Json(&input.workflow_task))
+        .fetch_optional(executor)
+        .await?;
+
+        if let Some(execution) = inserted {
+            return Ok(EnforcementExecutionCreateOrGetResult {
+                execution,
+                created: true,
+            });
+        }
+
+        let execution = Self::find_top_level_by_enforcement(executor, enforcement_id)
+            .await?
+            .ok_or_else(|| {
+                anyhow::anyhow!(
+                    "top-level execution for enforcement {} disappeared after dedupe conflict",
+                    enforcement_id
+                )
+            })?;
+
+        Ok(EnforcementExecutionCreateOrGetResult {
+            execution,
+            created: false,
+        })
+    }
+
+    async fn claim_workflow_task_dispatch<'e, E>(
+        executor: E,
+        workflow_execution_id: Id,
+        task_name: &str,
+        task_index: Option<i32>,
+    ) -> Result<bool>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        let inserted: Option<(i64,)> = sqlx::query_as(
+            "INSERT INTO workflow_task_dispatch (workflow_execution, task_name, task_index)
+             VALUES ($1, $2, $3)
+             ON CONFLICT (workflow_execution, task_name, COALESCE(task_index, -1)) DO NOTHING
+             RETURNING id",
+        )
+        .bind(workflow_execution_id)
+        .bind(task_name)
+        .bind(task_index)
+        .fetch_optional(executor)
+        .await?;
+
+        Ok(inserted.is_some())
+    }
+
+    async fn assign_workflow_task_dispatch_execution<'e, E>(
+        executor: E,
+        workflow_execution_id: Id,
+        task_name: &str,
+        task_index: Option<i32>,
+        execution_id: Id,
+    ) -> Result<()>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        sqlx::query(
+            "UPDATE workflow_task_dispatch
+             SET execution_id = COALESCE(execution_id, $4)
+             WHERE workflow_execution = $1
+               AND task_name = $2
+               AND task_index IS NOT DISTINCT FROM $3",
+        )
+        .bind(workflow_execution_id)
+        .bind(task_name)
+        .bind(task_index)
+        .bind(execution_id)
+        .execute(executor)
+        .await?;
+
+        Ok(())
+    }
+
+    async fn lock_workflow_task_dispatch<'e, E>(
+        executor: E,
+        workflow_execution_id: Id,
+        task_name: &str,
+        task_index: Option<i32>,
+    ) -> Result<Option<Option<Id>>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        let row: Option<(Option<i64>,)> = sqlx::query_as(
+            "SELECT execution_id
+             FROM workflow_task_dispatch
+             WHERE workflow_execution = $1
+               AND task_name = $2
+               AND task_index IS NOT DISTINCT FROM $3
+             FOR UPDATE",
+        )
+        .bind(workflow_execution_id)
+        .bind(task_name)
+        .bind(task_index)
+        .fetch_optional(executor)
+        .await?;
+
+        // Map the outer Option to distinguish three cases:
+        // - None            → no row exists
+        // - Some(None)      → row exists but execution_id is still NULL (mid-creation)
+        // - Some(Some(id))  → row exists with a completed execution_id
+        Ok(row.map(|(execution_id,)| execution_id))
+    }
+
+    async fn create_workflow_task_if_absent_in_conn(
+        conn: &mut PgConnection,
         input: CreateExecutionInput,
         workflow_execution_id: Id,
         task_name: &str,
         task_index: Option<i32>,
-    ) -> Result<WorkflowTaskExecutionCreateOrGetResult>
-    where
-        E: Executor<'e, Database = Postgres> + Copy + 'e,
-    {
-        if let Some(execution) =
-            Self::find_by_workflow_task(executor, workflow_execution_id, task_name, task_index)
-                .await?
-        {
+    ) -> Result<WorkflowTaskExecutionCreateOrGetResult> {
+        let claimed = Self::claim_workflow_task_dispatch(
+            &mut *conn,
+            workflow_execution_id,
+            task_name,
+            task_index,
+        )
+        .await?;
+
+        if claimed {
+            let execution = Self::create(&mut *conn, input).await?;
+            Self::assign_workflow_task_dispatch_execution(
+                &mut *conn,
+                workflow_execution_id,
+                task_name,
+                task_index,
+                execution.id,
+            )
+            .await?;
+
             return Ok(WorkflowTaskExecutionCreateOrGetResult {
                 execution,
-                created: false,
+                created: true,
             });
         }
 
-        let execution = Self::create(executor, input).await?;
+        let dispatch_state = Self::lock_workflow_task_dispatch(
+            &mut *conn,
+            workflow_execution_id,
+            task_name,
+            task_index,
+        )
+        .await?;
 
-        Ok(WorkflowTaskExecutionCreateOrGetResult {
-            execution,
-            created: true,
-        })
+        match dispatch_state {
+            Some(Some(existing_execution_id)) => {
+                // Row exists with execution_id — return the existing execution.
+                let execution = Self::find_by_id(&mut *conn, existing_execution_id)
+                    .await?
+                    .ok_or_else(|| {
+                        anyhow::anyhow!(
+                            "workflow child execution {} missing for workflow_execution {} task '{}' index {:?}",
+                            existing_execution_id,
+                            workflow_execution_id,
+                            task_name,
+                            task_index
+                        )
+                    })?;
+
+                Ok(WorkflowTaskExecutionCreateOrGetResult {
+                    execution,
+                    created: false,
+                })
+            }
+
+            Some(None) => {
+                // Row exists but execution_id is still NULL: another transaction is
+                // mid-creation (between claim and assign). Retry until it's filled in.
+                // If the original creator's transaction rolled back, the row also
+                // disappears — handled by the `None` branch inside the loop.
+                'wait: {
+                    for _ in 0..20_u32 {
+                        sleep(Duration::from_millis(50)).await;
+                        match Self::lock_workflow_task_dispatch(
+                            &mut *conn,
+                            workflow_execution_id,
+                            task_name,
+                            task_index,
+                        )
+                        .await?
+                        {
+                            Some(Some(execution_id)) => {
+                                let execution =
+                                    Self::find_by_id(&mut *conn, execution_id).await?.ok_or_else(
+                                        || {
+                                            anyhow::anyhow!(
+                                                "workflow child execution {} missing for workflow_execution {} task '{}' index {:?}",
+                                                execution_id,
+                                                workflow_execution_id,
+                                                task_name,
+                                                task_index
+                                            )
+                                        },
+                                    )?;
+                                return Ok(WorkflowTaskExecutionCreateOrGetResult {
+                                    execution,
+                                    created: false,
+                                });
+                            }
+                            Some(None) => {}     // still NULL, keep waiting
+                            None => break 'wait, // row rolled back; fall through to re-claim
+                        }
+                    }
+                    // Exhausted all retries without the execution_id being set.
+                    return Err(anyhow::anyhow!(
+                        "Timed out waiting for workflow task dispatch execution_id to be set \
+                         for workflow_execution {} task '{}' index {:?}",
+                        workflow_execution_id,
+                        task_name,
+                        task_index
+                    )
+                    .into());
+                }
+
+                // Row disappeared (original creator rolled back) — re-claim and create.
+                let re_claimed = Self::claim_workflow_task_dispatch(
+                    &mut *conn,
+                    workflow_execution_id,
+                    task_name,
+                    task_index,
+                )
+                .await?;
+                if !re_claimed {
+                    return Err(anyhow::anyhow!(
+                        "Workflow task dispatch for workflow_execution {} task '{}' index {:?} \
+                         was reclaimed by another executor after rollback",
+                        workflow_execution_id,
+                        task_name,
+                        task_index
+                    )
+                    .into());
+                }
+                let execution = Self::create(&mut *conn, input).await?;
+                Self::assign_workflow_task_dispatch_execution(
+                    &mut *conn,
+                    workflow_execution_id,
+                    task_name,
+                    task_index,
+                    execution.id,
+                )
+                .await?;
+                Ok(WorkflowTaskExecutionCreateOrGetResult {
+                    execution,
+                    created: true,
+                })
+            }
+
+            None => {
+                // No row at all — the original INSERT was rolled back before we arrived.
+                // Attempt to re-claim and create as if this were a fresh dispatch.
+                let re_claimed = Self::claim_workflow_task_dispatch(
+                    &mut *conn,
+                    workflow_execution_id,
+                    task_name,
+                    task_index,
+                )
+                .await?;
+                if !re_claimed {
+                    return Err(anyhow::anyhow!(
+                        "Workflow task dispatch for workflow_execution {} task '{}' index {:?} \
+                         was claimed by another executor",
+                        workflow_execution_id,
+                        task_name,
+                        task_index
+                    )
+                    .into());
+                }
+                let execution = Self::create(&mut *conn, input).await?;
+                Self::assign_workflow_task_dispatch_execution(
+                    &mut *conn,
+                    workflow_execution_id,
+                    task_name,
+                    task_index,
+                    execution.id,
+                )
+                .await?;
+                Ok(WorkflowTaskExecutionCreateOrGetResult {
+                    execution,
+                    created: true,
+                })
+            }
+        }
+    }
+
+    pub async fn create_workflow_task_if_absent(
+        pool: &PgPool,
+        input: CreateExecutionInput,
+        workflow_execution_id: Id,
+        task_name: &str,
+        task_index: Option<i32>,
+    ) -> Result<WorkflowTaskExecutionCreateOrGetResult> {
+        let mut conn = pool.acquire().await?;
+        sqlx::query("BEGIN").execute(&mut *conn).await?;
+
+        let result = Self::create_workflow_task_if_absent_in_conn(
+            &mut conn,
+            input,
+            workflow_execution_id,
+            task_name,
+            task_index,
+        )
+        .await;
+
+        match result {
+            Ok(result) => {
+                sqlx::query("COMMIT").execute(&mut *conn).await?;
+                Ok(result)
+            }
+            Err(err) => {
+                sqlx::query("ROLLBACK").execute(&mut *conn).await?;
+                Err(err)
+            }
+        }
+    }
+
+    pub async fn create_workflow_task_if_absent_with_conn(
+        conn: &mut PgConnection,
+        input: CreateExecutionInput,
+        workflow_execution_id: Id,
+        task_name: &str,
+        task_index: Option<i32>,
+    ) -> Result<WorkflowTaskExecutionCreateOrGetResult> {
+        Self::create_workflow_task_if_absent_in_conn(
+            conn,
+            input,
+            workflow_execution_id,
+            task_name,
+            task_index,
+        )
+        .await
     }
 
     pub async fn claim_for_scheduling<'e, E>(
@@ -320,6 +687,62 @@ impl ExecutionRepository {
         .await
     }
 
+    pub async fn update_if_status_and_updated_before<'e, E>(
+        executor: E,
+        id: Id,
+        expected_status: ExecutionStatus,
+        stale_before: DateTime<Utc>,
+        input: UpdateExecutionInput,
+    ) -> Result<Option<Execution>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        if input.status.is_none()
+            && input.result.is_none()
+            && input.executor.is_none()
+            && input.worker.is_none()
+            && input.started_at.is_none()
+            && input.workflow_task.is_none()
+        {
+            return Self::find_by_id(executor, id).await;
+        }
+
+        Self::update_with_locator_optional(executor, input, |query| {
+            query.push(" WHERE id = ").push_bind(id);
+            query.push(" AND status = ").push_bind(expected_status);
+            query.push(" AND updated < ").push_bind(stale_before);
+        })
+        .await
+    }
+
+    pub async fn update_if_status_and_updated_at<'e, E>(
+        executor: E,
+        id: Id,
+        expected_status: ExecutionStatus,
+        expected_updated: DateTime<Utc>,
+        input: UpdateExecutionInput,
+    ) -> Result<Option<Execution>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        if input.status.is_none()
+            && input.result.is_none()
+            && input.executor.is_none()
+            && input.worker.is_none()
+            && input.started_at.is_none()
+            && input.workflow_task.is_none()
+        {
+            return Self::find_by_id(executor, id).await;
+        }
+
+        Self::update_with_locator_optional(executor, input, |query| {
+            query.push(" WHERE id = ").push_bind(id);
+            query.push(" AND status = ").push_bind(expected_status);
+            query.push(" AND updated = ").push_bind(expected_updated);
+        })
+        .await
+    }
+
     pub async fn revert_scheduled_to_requested<'e, E>(
         executor: E,
         id: Id,
@@ -473,10 +896,7 @@ impl ExecutionRepository {
             .map_err(Into::into)
     }
 
-    /// Update an execution using the loaded row's hypertable keys.
-    ///
-    /// Including both the partition key (`created`) and compression segment key
-    /// (`action_ref`) avoids broad scans across compressed chunks.
+    /// Update an execution using the loaded row's primary key.
     pub async fn update_loaded<'e, E>(
         executor: E,
         execution: &Execution,
@@ -495,12 +915,8 @@ impl ExecutionRepository {
             return Ok(execution.clone());
         }
 
-        let action_ref = execution.action_ref.clone();
-
         Self::update_with_locator(executor, input, |query| {
             query.push(" WHERE id = ").push_bind(execution.id);
-            query.push(" AND created = ").push_bind(execution.created);
-            query.push(" AND action_ref = ").push_bind(action_ref);
         })
         .await
     }

crates/common/src/repositories/execution_admission.rs

@@ -0,0 +1,909 @@
+use chrono::{DateTime, Utc};
+use sqlx::{PgPool, Postgres, Row, Transaction};
+
+use crate::error::Result;
+use crate::models::Id;
+use crate::repositories::queue_stats::{QueueStatsRepository, UpsertQueueStatsInput};
+
+#[derive(Debug, Clone)]
+pub struct AdmissionSlotAcquireOutcome {
+    pub acquired: bool,
+    pub current_count: u32,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AdmissionEnqueueOutcome {
+    Acquired,
+    Enqueued,
+}
+
+#[derive(Debug, Clone)]
+pub struct AdmissionSlotReleaseOutcome {
+    pub action_id: Id,
+    pub group_key: Option<String>,
+    pub next_execution_id: Option<Id>,
+}
+
+#[derive(Debug, Clone)]
+pub struct AdmissionQueuedRemovalOutcome {
+    pub action_id: Id,
+    pub group_key: Option<String>,
+    pub next_execution_id: Option<Id>,
+    pub execution_id: Id,
+    pub queue_order: i64,
+    pub enqueued_at: DateTime<Utc>,
+    pub removed_index: usize,
+}
+
+#[derive(Debug, Clone)]
+pub struct AdmissionQueueStats {
+    pub action_id: Id,
+    pub queue_length: usize,
+    pub active_count: u32,
+    pub max_concurrent: u32,
+    pub oldest_enqueued_at: Option<DateTime<Utc>>,
+    pub total_enqueued: u64,
+    pub total_completed: u64,
+}
+
+#[derive(Debug, Clone)]
+struct AdmissionState {
+    id: Id,
+    action_id: Id,
+    group_key: Option<String>,
+    max_concurrent: i32,
+}
+
+#[derive(Debug, Clone)]
+struct ExecutionEntry {
+    state_id: Id,
+    action_id: Id,
+    group_key: Option<String>,
+    status: String,
+    queue_order: i64,
+    enqueued_at: DateTime<Utc>,
+}
+
+pub struct ExecutionAdmissionRepository;
+
+impl ExecutionAdmissionRepository {
+    pub async fn enqueue(
+        pool: &PgPool,
+        max_queue_length: usize,
+        action_id: Id,
+        execution_id: Id,
+        max_concurrent: u32,
+        group_key: Option<String>,
+    ) -> Result<AdmissionEnqueueOutcome> {
+        let mut tx = pool.begin().await?;
+        let state = Self::lock_state(&mut tx, action_id, group_key, max_concurrent).await?;
+        let outcome =
+            Self::enqueue_in_state(&mut tx, &state, max_queue_length, execution_id, true).await?;
+        Self::refresh_queue_stats(&mut tx, action_id).await?;
+        tx.commit().await?;
+        Ok(outcome)
+    }
+
+    pub async fn wait_status(pool: &PgPool, execution_id: Id) -> Result<Option<bool>> {
+        let row = sqlx::query_scalar::<Postgres, bool>(
+            r#"
+            SELECT status = 'active'
+            FROM execution_admission_entry
+            WHERE execution_id = $1
+            "#,
+        )
+        .bind(execution_id)
+        .fetch_optional(pool)
+        .await?;
+
+        Ok(row)
+    }
+
+    pub async fn try_acquire(
+        pool: &PgPool,
+        action_id: Id,
+        execution_id: Id,
+        max_concurrent: u32,
+        group_key: Option<String>,
+    ) -> Result<AdmissionSlotAcquireOutcome> {
+        let mut tx = pool.begin().await?;
+        let state = Self::lock_state(&mut tx, action_id, group_key, max_concurrent).await?;
+        let active_count = Self::active_count(&mut tx, state.id).await? as u32;
+
+        let outcome = match Self::find_execution_entry(&mut tx, execution_id).await? {
+            Some(entry) if entry.status == "active" => AdmissionSlotAcquireOutcome {
+                acquired: true,
+                current_count: active_count,
+            },
+            Some(entry) if entry.status == "queued" && entry.state_id == state.id => {
+                let promoted =
+                    Self::maybe_promote_existing_queued(&mut tx, &state, execution_id).await?;
+                AdmissionSlotAcquireOutcome {
+                    acquired: promoted,
+                    current_count: active_count,
+                }
+            }
+            Some(_) => AdmissionSlotAcquireOutcome {
+                acquired: false,
+                current_count: active_count,
+            },
+            None => {
+                if active_count < max_concurrent
+                    && Self::queued_count(&mut tx, state.id).await? == 0
+                {
+                    let queue_order = Self::allocate_queue_order(&mut tx, state.id).await?;
+                    Self::insert_entry(
+                        &mut tx,
+                        state.id,
+                        execution_id,
+                        "active",
+                        queue_order,
+                        Utc::now(),
+                    )
+                    .await?;
+                    Self::increment_total_enqueued(&mut tx, state.id).await?;
+                    Self::refresh_queue_stats(&mut tx, action_id).await?;
+                    AdmissionSlotAcquireOutcome {
+                        acquired: true,
+                        current_count: active_count,
+                    }
+                } else {
+                    AdmissionSlotAcquireOutcome {
+                        acquired: false,
+                        current_count: active_count,
+                    }
+                }
+            }
+        };
+
+        tx.commit().await?;
+        Ok(outcome)
+    }
+
+    pub async fn release_active_slot(
+        pool: &PgPool,
+        execution_id: Id,
+    ) -> Result<Option<AdmissionSlotReleaseOutcome>> {
+        let mut tx = pool.begin().await?;
+        let Some(entry) = Self::find_execution_entry_for_update(&mut tx, execution_id).await?
+        else {
+            tx.commit().await?;
+            return Ok(None);
+        };
+
+        if entry.status != "active" {
+            tx.commit().await?;
+            return Ok(None);
+        }
+
+        let state = Self::lock_existing_state(&mut tx, entry.action_id, entry.group_key.clone())
+            .await?
+            .ok_or_else(|| {
+                crate::Error::internal("missing execution_admission_state for active execution")
+            })?;
+
+        sqlx::query("DELETE FROM execution_admission_entry WHERE execution_id = $1")
+            .bind(execution_id)
+            .execute(&mut *tx)
+            .await?;
+
+        Self::increment_total_completed(&mut tx, state.id).await?;
+
+        let next_execution_id = Self::promote_next_queued(&mut tx, &state).await?;
+        Self::refresh_queue_stats(&mut tx, state.action_id).await?;
+        tx.commit().await?;
+
+        Ok(Some(AdmissionSlotReleaseOutcome {
+            action_id: state.action_id,
+            group_key: state.group_key,
+            next_execution_id,
+        }))
+    }
+
+    pub async fn restore_active_slot(
+        pool: &PgPool,
+        execution_id: Id,
+        outcome: &AdmissionSlotReleaseOutcome,
+    ) -> Result<()> {
+        let mut tx = pool.begin().await?;
+        let state =
+            Self::lock_existing_state(&mut tx, outcome.action_id, outcome.group_key.clone())
+                .await?
+                .ok_or_else(|| {
+                    crate::Error::internal("missing execution_admission_state on restore")
+                })?;
+
+        if let Some(next_execution_id) = outcome.next_execution_id {
+            sqlx::query(
+                r#"
+                UPDATE execution_admission_entry
+                SET status = 'queued', activated_at = NULL
+                WHERE execution_id = $1
+                  AND state_id = $2
+                  AND status = 'active'
+                "#,
+            )
+            .bind(next_execution_id)
+            .bind(state.id)
+            .execute(&mut *tx)
+            .await?;
+        }
+
+        sqlx::query(
+            r#"
+            INSERT INTO execution_admission_entry (
+                state_id, execution_id, status, queue_order, enqueued_at, activated_at
+            ) VALUES ($1, $2, 'active', $3, NOW(), NOW())
+            ON CONFLICT (execution_id) DO UPDATE
+            SET state_id = EXCLUDED.state_id,
+                status = 'active',
+                activated_at = EXCLUDED.activated_at
+            "#,
+        )
+        .bind(state.id)
+        .bind(execution_id)
+        .bind(Self::allocate_queue_order(&mut tx, state.id).await?)
+        .execute(&mut *tx)
+        .await?;
+
+        sqlx::query(
+            r#"
+            UPDATE execution_admission_state
+            SET total_completed = GREATEST(total_completed - 1, 0)
+            WHERE id = $1
+            "#,
+        )
+        .bind(state.id)
+        .execute(&mut *tx)
+        .await?;
+
+        Self::refresh_queue_stats(&mut tx, state.action_id).await?;
+        tx.commit().await?;
+        Ok(())
+    }
+
+    pub async fn remove_queued_execution(
+        pool: &PgPool,
+        execution_id: Id,
+    ) -> Result<Option<AdmissionQueuedRemovalOutcome>> {
+        let mut tx = pool.begin().await?;
+        let Some(entry) = Self::find_execution_entry_for_update(&mut tx, execution_id).await?
+        else {
+            tx.commit().await?;
+            return Ok(None);
+        };
+
+        if entry.status != "queued" {
+            tx.commit().await?;
+            return Ok(None);
+        }
+
+        let state = Self::lock_existing_state(&mut tx, entry.action_id, entry.group_key.clone())
+            .await?
+            .ok_or_else(|| {
+                crate::Error::internal("missing execution_admission_state for queued execution")
+            })?;
+
+        let removed_index = sqlx::query_scalar::<Postgres, i64>(
+            r#"
+            SELECT COUNT(*)
+            FROM execution_admission_entry
+            WHERE state_id = $1
+              AND status = 'queued'
+              AND (enqueued_at, id) < (
+                    SELECT enqueued_at, id
+                    FROM execution_admission_entry
+                    WHERE execution_id = $2
+                )
+            "#,
+        )
+        .bind(state.id)
+        .bind(execution_id)
+        .fetch_one(&mut *tx)
+        .await? as usize;
+
+        sqlx::query("DELETE FROM execution_admission_entry WHERE execution_id = $1")
+            .bind(execution_id)
+            .execute(&mut *tx)
+            .await?;
+
+        let next_execution_id =
+            if Self::active_count(&mut tx, state.id).await? < state.max_concurrent as i64 {
+                Self::promote_next_queued(&mut tx, &state).await?
+            } else {
+                None
+            };
+
+        Self::refresh_queue_stats(&mut tx, state.action_id).await?;
+        tx.commit().await?;
+
+        Ok(Some(AdmissionQueuedRemovalOutcome {
+            action_id: state.action_id,
+            group_key: state.group_key,
+            next_execution_id,
+            execution_id,
+            queue_order: entry.queue_order,
+            enqueued_at: entry.enqueued_at,
+            removed_index,
+        }))
+    }
+
+    pub async fn restore_queued_execution(
+        pool: &PgPool,
+        outcome: &AdmissionQueuedRemovalOutcome,
+    ) -> Result<()> {
+        let mut tx = pool.begin().await?;
+        let state =
+            Self::lock_existing_state(&mut tx, outcome.action_id, outcome.group_key.clone())
+                .await?
+                .ok_or_else(|| {
+                    crate::Error::internal("missing execution_admission_state on queued restore")
+                })?;
+
+        if let Some(next_execution_id) = outcome.next_execution_id {
+            sqlx::query(
+                r#"
+                UPDATE execution_admission_entry
+                SET status = 'queued', activated_at = NULL
+                WHERE execution_id = $1
+                  AND state_id = $2
+                  AND status = 'active'
+                "#,
+            )
+            .bind(next_execution_id)
+            .bind(state.id)
+            .execute(&mut *tx)
+            .await?;
+        }
+
+        sqlx::query(
+            r#"
+            INSERT INTO execution_admission_entry (
+                state_id, execution_id, status, queue_order, enqueued_at, activated_at
+            ) VALUES ($1, $2, 'queued', $3, $4, NULL)
+            ON CONFLICT (execution_id) DO NOTHING
+            "#,
+        )
+        .bind(state.id)
+        .bind(outcome.execution_id)
+        .bind(outcome.queue_order)
+        .bind(outcome.enqueued_at)
+        .execute(&mut *tx)
+        .await?;
+
+        Self::refresh_queue_stats(&mut tx, state.action_id).await?;
+        tx.commit().await?;
+        Ok(())
+    }
+
+    pub async fn get_queue_stats(
+        pool: &PgPool,
+        action_id: Id,
+    ) -> Result<Option<AdmissionQueueStats>> {
+        let row = sqlx::query(
+            r#"
+            WITH state_rows AS (
+                SELECT
+                    COUNT(*) AS state_count,
+                    COALESCE(SUM(max_concurrent), 0) AS max_concurrent,
+                    COALESCE(SUM(total_enqueued), 0) AS total_enqueued,
+                    COALESCE(SUM(total_completed), 0) AS total_completed
+                FROM execution_admission_state
+                WHERE action_id = $1
+            ),
+            entry_rows AS (
+                SELECT
+                    COUNT(*) FILTER (WHERE e.status = 'queued') AS queue_length,
+                    COUNT(*) FILTER (WHERE e.status = 'active') AS active_count,
+                    MIN(e.enqueued_at) FILTER (WHERE e.status = 'queued') AS oldest_enqueued_at
+                FROM execution_admission_state s
+                LEFT JOIN execution_admission_entry e ON e.state_id = s.id
+                WHERE s.action_id = $1
+            )
+            SELECT
+                sr.state_count,
+                er.queue_length,
+                er.active_count,
+                sr.max_concurrent,
+                er.oldest_enqueued_at,
+                sr.total_enqueued,
+                sr.total_completed
+            FROM state_rows sr
+            CROSS JOIN entry_rows er
+            "#,
+        )
+        .bind(action_id)
+        .fetch_one(pool)
+        .await?;
+
+        let state_count: i64 = row.try_get("state_count")?;
+        if state_count == 0 {
+            return Ok(None);
+        }
+
+        Ok(Some(AdmissionQueueStats {
+            action_id,
+            queue_length: row.try_get::<i64, _>("queue_length")? as usize,
+            active_count: row.try_get::<i64, _>("active_count")? as u32,
+            max_concurrent: row.try_get::<i64, _>("max_concurrent")? as u32,
+            oldest_enqueued_at: row.try_get("oldest_enqueued_at")?,
+            total_enqueued: row.try_get::<i64, _>("total_enqueued")? as u64,
+            total_completed: row.try_get::<i64, _>("total_completed")? as u64,
+        }))
+    }
+
+    async fn enqueue_in_state(
+        tx: &mut Transaction<'_, Postgres>,
+        state: &AdmissionState,
+        max_queue_length: usize,
+        execution_id: Id,
+        allow_queue: bool,
+    ) -> Result<AdmissionEnqueueOutcome> {
+        if let Some(entry) = Self::find_execution_entry(tx, execution_id).await? {
+            if entry.status == "active" {
+                return Ok(AdmissionEnqueueOutcome::Acquired);
+            }
+
+            if entry.status == "queued" && entry.state_id == state.id {
+                if Self::maybe_promote_existing_queued(tx, state, execution_id).await? {
+                    return Ok(AdmissionEnqueueOutcome::Acquired);
+                }
+                return Ok(AdmissionEnqueueOutcome::Enqueued);
+            }
+
+            return Ok(AdmissionEnqueueOutcome::Enqueued);
+        }
+
+        let active_count = Self::active_count(tx, state.id).await?;
+        let queued_count = Self::queued_count(tx, state.id).await?;
+
+        if active_count < state.max_concurrent as i64 && queued_count == 0 {
+            let queue_order = Self::allocate_queue_order(tx, state.id).await?;
+            Self::insert_entry(
+                tx,
+                state.id,
+                execution_id,
+                "active",
+                queue_order,
+                Utc::now(),
+            )
+            .await?;
+            Self::increment_total_enqueued(tx, state.id).await?;
+            return Ok(AdmissionEnqueueOutcome::Acquired);
+        }
+
+        if !allow_queue {
+            return Ok(AdmissionEnqueueOutcome::Enqueued);
+        }
+
+        if queued_count >= max_queue_length as i64 {
+            return Err(anyhow::anyhow!(
+                "Queue full for action {}: maximum {} entries",
+                state.action_id,
+                max_queue_length
+            )
+            .into());
+        }
+
+        let queue_order = Self::allocate_queue_order(tx, state.id).await?;
+        Self::insert_entry(
+            tx,
+            state.id,
+            execution_id,
+            "queued",
+            queue_order,
+            Utc::now(),
+        )
+        .await?;
+        Self::increment_total_enqueued(tx, state.id).await?;
+        Ok(AdmissionEnqueueOutcome::Enqueued)
+    }
+
+    async fn maybe_promote_existing_queued(
+        tx: &mut Transaction<'_, Postgres>,
+        state: &AdmissionState,
+        execution_id: Id,
+    ) -> Result<bool> {
+        let active_count = Self::active_count(tx, state.id).await?;
+        if active_count >= state.max_concurrent as i64 {
+            return Ok(false);
+        }
+
+        let front_execution_id = sqlx::query_scalar::<Postgres, Id>(
+            r#"
+            SELECT execution_id
+            FROM execution_admission_entry
+            WHERE state_id = $1
+              AND status = 'queued'
+            ORDER BY queue_order ASC
+            LIMIT 1
+            "#,
+        )
+        .bind(state.id)
+        .fetch_optional(&mut **tx)
+        .await?;
+
+        if front_execution_id != Some(execution_id) {
+            return Ok(false);
+        }
+
+        sqlx::query(
+            r#"
+            UPDATE execution_admission_entry
+            SET status = 'active',
+                activated_at = NOW()
+            WHERE execution_id = $1
+              AND state_id = $2
+              AND status = 'queued'
+            "#,
+        )
+        .bind(execution_id)
+        .bind(state.id)
+        .execute(&mut **tx)
+        .await?;
+
+        Ok(true)
+    }
+
+    async fn promote_next_queued(
+        tx: &mut Transaction<'_, Postgres>,
+        state: &AdmissionState,
+    ) -> Result<Option<Id>> {
+        let next_execution_id = sqlx::query_scalar::<Postgres, Id>(
+            r#"
+            SELECT execution_id
+            FROM execution_admission_entry
+            WHERE state_id = $1
+              AND status = 'queued'
+            ORDER BY queue_order ASC
+            LIMIT 1
+            "#,
+        )
+        .bind(state.id)
+        .fetch_optional(&mut **tx)
+        .await?;
+
+        if let Some(next_execution_id) = next_execution_id {
+            sqlx::query(
+                r#"
+                UPDATE execution_admission_entry
+                SET status = 'active',
+                    activated_at = NOW()
+                WHERE execution_id = $1
+                  AND state_id = $2
+                  AND status = 'queued'
+                "#,
+            )
+            .bind(next_execution_id)
+            .bind(state.id)
+            .execute(&mut **tx)
+            .await?;
+        }
+
+        Ok(next_execution_id)
+    }
+
+    async fn lock_state(
+        tx: &mut Transaction<'_, Postgres>,
+        action_id: Id,
+        group_key: Option<String>,
+        max_concurrent: u32,
+    ) -> Result<AdmissionState> {
+        sqlx::query(
+            r#"
+            INSERT INTO execution_admission_state (action_id, group_key, max_concurrent)
+            VALUES ($1, $2, $3)
+            ON CONFLICT (action_id, group_key_normalized)
+            DO UPDATE SET max_concurrent = EXCLUDED.max_concurrent
+            "#,
+        )
+        .bind(action_id)
+        .bind(group_key.clone())
+        .bind(max_concurrent as i32)
+        .execute(&mut **tx)
+        .await?;
+
+        let state = sqlx::query(
+            r#"
+            SELECT id, action_id, group_key, max_concurrent
+            FROM execution_admission_state
+            WHERE action_id = $1
+              AND group_key_normalized = COALESCE($2, '')
+            FOR UPDATE
+            "#,
+        )
+        .bind(action_id)
+        .bind(group_key)
+        .fetch_one(&mut **tx)
+        .await?;
+
+        Ok(AdmissionState {
+            id: state.try_get("id")?,
+            action_id: state.try_get("action_id")?,
+            group_key: state.try_get("group_key")?,
+            max_concurrent: state.try_get("max_concurrent")?,
+        })
+    }
+
+    async fn lock_existing_state(
+        tx: &mut Transaction<'_, Postgres>,
+        action_id: Id,
+        group_key: Option<String>,
+    ) -> Result<Option<AdmissionState>> {
+        let row = sqlx::query(
+            r#"
+            SELECT id, action_id, group_key, max_concurrent
+            FROM execution_admission_state
+            WHERE action_id = $1
+              AND group_key_normalized = COALESCE($2, '')
+            FOR UPDATE
+            "#,
+        )
+        .bind(action_id)
+        .bind(group_key)
+        .fetch_optional(&mut **tx)
+        .await?;
+
+        Ok(row.map(|state| AdmissionState {
+            id: state.try_get("id").expect("state.id"),
+            action_id: state.try_get("action_id").expect("state.action_id"),
+            group_key: state.try_get("group_key").expect("state.group_key"),
+            max_concurrent: state
+                .try_get("max_concurrent")
+                .expect("state.max_concurrent"),
+        }))
+    }
+
+    async fn find_execution_entry(
+        tx: &mut Transaction<'_, Postgres>,
+        execution_id: Id,
+    ) -> Result<Option<ExecutionEntry>> {
+        let row = sqlx::query(
+            r#"
+            SELECT
+                e.state_id,
+                s.action_id,
+                s.group_key,
+                e.execution_id,
+                e.status,
+                e.queue_order,
+                e.enqueued_at
+            FROM execution_admission_entry e
+            JOIN execution_admission_state s ON s.id = e.state_id
+            WHERE e.execution_id = $1
+            "#,
+        )
+        .bind(execution_id)
+        .fetch_optional(&mut **tx)
+        .await?;
+
+        Ok(row.map(|entry| ExecutionEntry {
+            state_id: entry.try_get("state_id").expect("entry.state_id"),
+            action_id: entry.try_get("action_id").expect("entry.action_id"),
+            group_key: entry.try_get("group_key").expect("entry.group_key"),
+            status: entry.try_get("status").expect("entry.status"),
+            queue_order: entry.try_get("queue_order").expect("entry.queue_order"),
+            enqueued_at: entry.try_get("enqueued_at").expect("entry.enqueued_at"),
+        }))
+    }
+
+    async fn find_execution_entry_for_update(
+        tx: &mut Transaction<'_, Postgres>,
+        execution_id: Id,
+    ) -> Result<Option<ExecutionEntry>> {
+        let row = sqlx::query(
+            r#"
+            SELECT
+                e.state_id,
+                s.action_id,
+                s.group_key,
+                e.execution_id,
+                e.status,
+                e.queue_order,
+                e.enqueued_at
+            FROM execution_admission_entry e
+            JOIN execution_admission_state s ON s.id = e.state_id
+            WHERE e.execution_id = $1
+            FOR UPDATE OF e, s
+            "#,
+        )
+        .bind(execution_id)
+        .fetch_optional(&mut **tx)
+        .await?;
+
+        Ok(row.map(|entry| ExecutionEntry {
+            state_id: entry.try_get("state_id").expect("entry.state_id"),
+            action_id: entry.try_get("action_id").expect("entry.action_id"),
+            group_key: entry.try_get("group_key").expect("entry.group_key"),
+            status: entry.try_get("status").expect("entry.status"),
+            queue_order: entry.try_get("queue_order").expect("entry.queue_order"),
+            enqueued_at: entry.try_get("enqueued_at").expect("entry.enqueued_at"),
+        }))
+    }
+
+    async fn active_count(tx: &mut Transaction<'_, Postgres>, state_id: Id) -> Result<i64> {
+        Ok(sqlx::query_scalar::<Postgres, i64>(
+            r#"
+            SELECT COUNT(*)
+            FROM execution_admission_entry
+            WHERE state_id = $1
+              AND status = 'active'
+            "#,
+        )
+        .bind(state_id)
+        .fetch_one(&mut **tx)
+        .await?)
+    }
+
+    async fn queued_count(tx: &mut Transaction<'_, Postgres>, state_id: Id) -> Result<i64> {
+        Ok(sqlx::query_scalar::<Postgres, i64>(
+            r#"
+            SELECT COUNT(*)
+            FROM execution_admission_entry
+            WHERE state_id = $1
+              AND status = 'queued'
+            "#,
+        )
+        .bind(state_id)
+        .fetch_one(&mut **tx)
+        .await?)
+    }
+
+    async fn insert_entry(
+        tx: &mut Transaction<'_, Postgres>,
+        state_id: Id,
+        execution_id: Id,
+        status: &str,
+        queue_order: i64,
+        enqueued_at: DateTime<Utc>,
+    ) -> Result<()> {
+        sqlx::query(
+            r#"
+            INSERT INTO execution_admission_entry (
+                state_id, execution_id, status, queue_order, enqueued_at, activated_at
+            ) VALUES (
+                $1, $2, $3, $4, $5,
+                CASE WHEN $3 = 'active' THEN NOW() ELSE NULL END
+            )
+            "#,
+        )
+        .bind(state_id)
+        .bind(execution_id)
+        .bind(status)
+        .bind(queue_order)
+        .bind(enqueued_at)
+        .execute(&mut **tx)
+        .await?;
+
+        Ok(())
+    }
+
+    async fn allocate_queue_order(tx: &mut Transaction<'_, Postgres>, state_id: Id) -> Result<i64> {
+        let queue_order = sqlx::query_scalar::<Postgres, i64>(
+            r#"
+            UPDATE execution_admission_state
+            SET next_queue_order = next_queue_order + 1
+            WHERE id = $1
+            RETURNING next_queue_order - 1
+            "#,
+        )
+        .bind(state_id)
+        .fetch_one(&mut **tx)
+        .await?;
+
+        Ok(queue_order)
+    }
+
+    async fn increment_total_enqueued(
+        tx: &mut Transaction<'_, Postgres>,
+        state_id: Id,
+    ) -> Result<()> {
+        sqlx::query(
+            r#"
+            UPDATE execution_admission_state
+            SET total_enqueued = total_enqueued + 1
+            WHERE id = $1
+            "#,
+        )
+        .bind(state_id)
+        .execute(&mut **tx)
+        .await?;
+        Ok(())
+    }
+
+    async fn increment_total_completed(
+        tx: &mut Transaction<'_, Postgres>,
+        state_id: Id,
+    ) -> Result<()> {
+        sqlx::query(
+            r#"
+            UPDATE execution_admission_state
+            SET total_completed = total_completed + 1
+            WHERE id = $1
+            "#,
+        )
+        .bind(state_id)
+        .execute(&mut **tx)
+        .await?;
+        Ok(())
+    }
+
+    async fn refresh_queue_stats(tx: &mut Transaction<'_, Postgres>, action_id: Id) -> Result<()> {
+        let Some(stats) = Self::get_queue_stats_from_tx(tx, action_id).await? else {
+            QueueStatsRepository::delete(&mut **tx, action_id).await?;
+            return Ok(());
+        };
+
+        QueueStatsRepository::upsert(
+            &mut **tx,
+            UpsertQueueStatsInput {
+                action_id,
+                queue_length: stats.queue_length as i32,
+                active_count: stats.active_count as i32,
+                max_concurrent: stats.max_concurrent as i32,
+                oldest_enqueued_at: stats.oldest_enqueued_at,
+                total_enqueued: stats.total_enqueued as i64,
+                total_completed: stats.total_completed as i64,
+            },
+        )
+        .await?;
+
+        Ok(())
+    }
+
+    async fn get_queue_stats_from_tx(
+        tx: &mut Transaction<'_, Postgres>,
+        action_id: Id,
+    ) -> Result<Option<AdmissionQueueStats>> {
+        let row = sqlx::query(
+            r#"
+            WITH state_rows AS (
+                SELECT
+                    COUNT(*) AS state_count,
+                    COALESCE(SUM(max_concurrent), 0) AS max_concurrent,
+                    COALESCE(SUM(total_enqueued), 0) AS total_enqueued,
+                    COALESCE(SUM(total_completed), 0) AS total_completed
+                FROM execution_admission_state
+                WHERE action_id = $1
+            ),
+            entry_rows AS (
+                SELECT
+                    COUNT(*) FILTER (WHERE e.status = 'queued') AS queue_length,
+                    COUNT(*) FILTER (WHERE e.status = 'active') AS active_count,
+                    MIN(e.enqueued_at) FILTER (WHERE e.status = 'queued') AS oldest_enqueued_at
+                FROM execution_admission_state s
+                LEFT JOIN execution_admission_entry e ON e.state_id = s.id
+                WHERE s.action_id = $1
+            )
+            SELECT
+                sr.state_count,
+                er.queue_length,
+                er.active_count,
+                sr.max_concurrent,
+                er.oldest_enqueued_at,
+                sr.total_enqueued,
+                sr.total_completed
+            FROM state_rows sr
+            CROSS JOIN entry_rows er
+            "#,
+        )
+        .bind(action_id)
+        .fetch_one(&mut **tx)
+        .await?;
+
+        let state_count: i64 = row.try_get("state_count")?;
+        if state_count == 0 {
+            return Ok(None);
+        }
+
+        Ok(Some(AdmissionQueueStats {
+            action_id,
+            queue_length: row.try_get::<i64, _>("queue_length")? as usize,
+            active_count: row.try_get::<i64, _>("active_count")? as u32,
+            max_concurrent: row.try_get::<i64, _>("max_concurrent")? as u32,
+            oldest_enqueued_at: row.try_get("oldest_enqueued_at")?,
+            total_enqueued: row.try_get::<i64, _>("total_enqueued")? as u64,
+            total_completed: row.try_get::<i64, _>("total_completed")? as u64,
+        }))
+    }
+}

crates/common/src/repositories/mod.rs

@@ -33,6 +33,7 @@ pub mod artifact;
 pub mod entity_history;
 pub mod event;
 pub mod execution;
+pub mod execution_admission;
 pub mod identity;
 pub mod inquiry;
 pub mod key;
@@ -53,6 +54,7 @@ pub use artifact::{ArtifactRepository, ArtifactVersionRepository};
 pub use entity_history::EntityHistoryRepository;
 pub use event::{EnforcementRepository, EventRepository};
 pub use execution::ExecutionRepository;
+pub use execution_admission::ExecutionAdmissionRepository;
 pub use identity::{IdentityRepository, PermissionAssignmentRepository, PermissionSetRepository};
 pub use inquiry::InquiryRepository;
 pub use key::KeyRepository;

crates/common/src/repositories/queue_stats.rs

@@ -3,7 +3,7 @@
 //! Provides database operations for queue statistics persistence.
 
 use chrono::{DateTime, Utc};
-use sqlx::{PgPool, Postgres, QueryBuilder};
+use sqlx::{Executor, PgPool, Postgres, QueryBuilder};
 
 use crate::error::Result;
 use crate::models::Id;
@@ -38,7 +38,10 @@ pub struct QueueStatsRepository;
 
 impl QueueStatsRepository {
     /// Upsert queue statistics (insert or update)
-    pub async fn upsert(pool: &PgPool, input: UpsertQueueStatsInput) -> Result<QueueStats> {
+    pub async fn upsert<'e, E>(executor: E, input: UpsertQueueStatsInput) -> Result<QueueStats>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let stats = sqlx::query_as::<Postgres, QueueStats>(
             r#"
             INSERT INTO queue_stats (
@@ -69,14 +72,17 @@ impl QueueStatsRepository {
         .bind(input.oldest_enqueued_at)
         .bind(input.total_enqueued)
         .bind(input.total_completed)
-        .fetch_one(pool)
+        .fetch_one(executor)
         .await?;
 
         Ok(stats)
     }
 
     /// Get queue statistics for a specific action
-    pub async fn find_by_action(pool: &PgPool, action_id: Id) -> Result<Option<QueueStats>> {
+    pub async fn find_by_action<'e, E>(executor: E, action_id: Id) -> Result<Option<QueueStats>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let stats = sqlx::query_as::<Postgres, QueueStats>(
             r#"
             SELECT
@@ -93,14 +99,17 @@ impl QueueStatsRepository {
             "#,
         )
         .bind(action_id)
-        .fetch_optional(pool)
+        .fetch_optional(executor)
         .await?;
 
         Ok(stats)
     }
 
     /// List all queue statistics with active queues (queue_length > 0 or active_count > 0)
-    pub async fn list_active(pool: &PgPool) -> Result<Vec<QueueStats>> {
+    pub async fn list_active<'e, E>(executor: E) -> Result<Vec<QueueStats>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let stats = sqlx::query_as::<Postgres, QueueStats>(
             r#"
             SELECT
@@ -117,14 +126,17 @@ impl QueueStatsRepository {
             ORDER BY last_updated DESC
             "#,
         )
-        .fetch_all(pool)
+        .fetch_all(executor)
         .await?;
 
         Ok(stats)
     }
 
     /// List all queue statistics
-    pub async fn list_all(pool: &PgPool) -> Result<Vec<QueueStats>> {
+    pub async fn list_all<'e, E>(executor: E) -> Result<Vec<QueueStats>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let stats = sqlx::query_as::<Postgres, QueueStats>(
             r#"
             SELECT
@@ -140,14 +152,17 @@ impl QueueStatsRepository {
             ORDER BY last_updated DESC
             "#,
         )
-        .fetch_all(pool)
+        .fetch_all(executor)
         .await?;
 
         Ok(stats)
     }
 
     /// Delete queue statistics for a specific action
-    pub async fn delete(pool: &PgPool, action_id: Id) -> Result<bool> {
+    pub async fn delete<'e, E>(executor: E, action_id: Id) -> Result<bool>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let result = sqlx::query(
             r#"
             DELETE FROM queue_stats
@@ -155,7 +170,7 @@ impl QueueStatsRepository {
             "#,
         )
         .bind(action_id)
-        .execute(pool)
+        .execute(executor)
         .await?;
 
         Ok(result.rows_affected() > 0)
@@ -163,7 +178,7 @@ impl QueueStatsRepository {
 
     /// Batch upsert multiple queue statistics
     pub async fn batch_upsert(
-        pool: &PgPool,
+        executor: &PgPool,
         inputs: Vec<UpsertQueueStatsInput>,
     ) -> Result<Vec<QueueStats>> {
         if inputs.is_empty() {
@@ -213,14 +228,17 @@ impl QueueStatsRepository {
 
         let stats = query_builder
             .build_query_as::<QueueStats>()
-            .fetch_all(pool)
+            .fetch_all(executor)
             .await?;
 
         Ok(stats)
     }
 
     /// Clear stale statistics (older than specified duration)
-    pub async fn clear_stale(pool: &PgPool, older_than_seconds: i64) -> Result<u64> {
+    pub async fn clear_stale<'e, E>(executor: E, older_than_seconds: i64) -> Result<u64>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
         let result = sqlx::query(
             r#"
             DELETE FROM queue_stats
@@ -230,7 +248,7 @@ impl QueueStatsRepository {
             "#,
         )
         .bind(older_than_seconds)
-        .execute(pool)
+        .execute(executor)
         .await?;
 
         Ok(result.rows_affected())

crates/common/src/repositories/workflow.rs

@@ -612,6 +612,26 @@ impl Delete for WorkflowExecutionRepository {
 }
 
 impl WorkflowExecutionRepository {
+    pub async fn find_by_id_for_update<'e, E>(
+        executor: E,
+        id: Id,
+    ) -> Result<Option<WorkflowExecution>>
+    where
+        E: Executor<'e, Database = Postgres> + 'e,
+    {
+        sqlx::query_as::<_, WorkflowExecution>(
+            "SELECT id, execution, workflow_def, current_tasks, completed_tasks, failed_tasks, skipped_tasks,
+                    variables, task_graph, status, error_message, paused, pause_reason, created, updated
+             FROM workflow_execution
+             WHERE id = $1
+             FOR UPDATE"
+        )
+        .bind(id)
+        .fetch_optional(executor)
+        .await
+        .map_err(Into::into)
+    }
+
     pub async fn create_or_get_by_execution<'e, E>(
         executor: E,
         input: CreateWorkflowExecutionInput,