SQL pools time out; task locks are a renewed five-minute lease

A 3-node rehearsal (PostgreSQL + NATS + Garage) found two ways a crash
leaves work stuck:

Pool hangs. The PostgreSQL pool (deadpool) was built with no timeouts,
so a request waited for a free connection, and for one to be opened or
recycled, for as long as it took: forever when the server stopped
answering. MySQL's pool (mysql_async) has no wait timeout at all.

- PostgreSQL: wait 30 s (or the store's timeout if longer), create the
  store's timeout or 15 s (it bounds the whole handshake, where
  tokio-postgres's connect_timeout covers only the TCP connect), recycle
  10 s. The pool config is now always set, not only with
  poolMaxConnections.
- MySQL: every connection is taken through MysqlStore::conn(), which
  gives up after 30 s.
- Both: TCP keepalive after 60 s idle, so a server that vanished
  without closing the connection is noticed in minutes rather than the
  two-hour system default.

The DataStore schema has no pool timeout settings, so these are fixed
defaults; the store's own timeout bounds connecting on PostgreSQL.

Task locks. A task lock lasted an hour, so after a hard crash the dead
node's tasks waited up to an hour and five minutes. The lock is now a
five-minute lease: while this node runs a task, the task manager renews
its lock every third of the lifetime (InMemoryStore::renew_lock, a
compare-and-set on the store backends and SET XX EX on Redis, which
leaves a lock that already expired alone). A killed node's tasks run
elsewhere within about five minutes plus the claim recheck. A task this
node holds isn't handed to a worker again by the scan.

store::pool_timeout (new): a local listener that accepts connections
and never answers plays a hung server; a PostgreSQL store with a 2 s
timeout returns an error in about 4 s, and a MySQL store in 30 s.
Without the timeouts both wait for good. store::task_locks gains a
task held for 1.5 lock lifetimes: its lease is still held, and released
when the task ends.

crates/store/src/backend/mysql/blob.rs

@@ -2,6 +2,8 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
 use std::ops::Range;
@@ -16,7 +18,7 @@ impl MysqlStore {
         key: &[u8],
         range: Range<usize>,
     ) -> trc::Result<Option<Vec<u8>>> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep("SELECT v FROM t WHERE k = ?")
             .await
@@ -39,7 +41,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn put_blob(&self, key: &[u8], data: &[u8]) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep("INSERT INTO t (k, v) VALUES (?, ?) ON DUPLICATE KEY UPDATE v = VALUES(v)")
             .await
@@ -51,7 +53,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn delete_blob(&self, key: &[u8]) -> trc::Result<bool> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep("DELETE FROM t WHERE k = ?")
             .await

crates/store/src/backend/mysql/lookup.rs

@@ -2,6 +2,8 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
 use mysql_async::{Params, Row, prelude::Queryable};
@@ -16,7 +18,7 @@ impl MysqlStore {
         query: &str,
         params: &[Value<'_>],
     ) -> trc::Result<T> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn.prep(query).await.map_err(into_error)?;
         let params = Params::Positional(params.iter().map(Into::into).collect());
 

crates/store/src/backend/mysql/main.rs

@@ -32,6 +32,9 @@ impl MysqlStore {
             .max_allowed_packet(config.max_allowed_packet.map(|v| v as usize))
             .wait_timeout(config.timeout.map(|t| t.as_secs() as usize))
             .client_found_rows(true)
+            // inbuxa: notice a server that went away without closing the
+            // connection in minutes, not the system default of two hours
+            .tcp_keepalive(Some(super::POOL_KEEPALIVE_IDLE))
             .tcp_port(config.port as u16);
 
         if config.use_tls {
@@ -95,7 +98,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn create_storage_tables(&self) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
 
         for table in [
             SUBSPACE_ACL,
@@ -169,7 +172,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn create_search_tables(&self) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
 
         create_search_tables::<EmailSearchField>(&mut conn).await?;
         create_search_tables::<CalendarSearchField>(&mut conn).await?;

crates/store/src/backend/mysql/mod.rs

@@ -27,6 +27,33 @@ pub struct MysqlStore {
     pub(crate) conn_pool: Pool,
 }
 
+/// inbuxa: how long a request waits for a pooled connection (including
+/// opening one). mysql_async's pool has no wait timeout, so upstream waited
+/// forever when the server stopped answering.
+pub(crate) const POOL_WAIT_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(30);
+/// inbuxa: idle time before TCP keepalive probes start.
+pub(crate) const POOL_KEEPALIVE_IDLE: std::time::Duration = std::time::Duration::from_secs(60);
+
+impl MysqlStore {
+    /// inbuxa: a pooled connection, or an error once POOL_WAIT_TIMEOUT has
+    /// passed without one.
+    pub(crate) async fn conn(&self) -> trc::Result<mysql_async::Conn> {
+        pool_conn(&self.conn_pool, POOL_WAIT_TIMEOUT).await
+    }
+}
+
+pub(crate) async fn pool_conn(
+    pool: &Pool,
+    wait: std::time::Duration,
+) -> trc::Result<mysql_async::Conn> {
+    match tokio::time::timeout(wait, pool.get_conn()).await {
+        Ok(result) => result.map_err(into_error),
+        Err(_) => Err(trc::StoreEvent::MysqlError
+            .reason("Timed out waiting for a database connection")
+            .details(format!("No connection within {} s", wait.as_secs()))),
+    }
+}
+
 #[inline(always)]
 pub(crate) fn into_error(err: impl Display) -> trc::Error {
     trc::StoreEvent::MysqlError.reason(err)

crates/store/src/backend/mysql/read.rs

@@ -2,6 +2,8 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
 use super::{MysqlStore, into_error, is_timeout_error};
@@ -14,7 +16,7 @@ impl MysqlStore {
     where
         U: Deserialize + 'static,
     {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep(format!(
                 "SELECT v FROM {} WHERE k = ?",
@@ -36,7 +38,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn key_exists(&self, key: impl Key) -> trc::Result<bool> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep(format!(
                 "SELECT 1 FROM {} WHERE k = ?",
@@ -56,7 +58,7 @@ impl MysqlStore {
         params: IterateParams<T>,
         mut cb: impl for<'x> FnMut(&'x [u8], &'x [u8]) -> trc::Result<bool> + Sync + Send,
     ) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let table = char::from(params.begin.subspace());
         let begin = params.begin.serialize(0);
         let end = params.end.serialize(0);
@@ -155,7 +157,7 @@ impl MysqlStore {
         let key = key.into();
         let table = char::from(key.subspace());
         let key = key.serialize(0);
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn
             .prep(format!("SELECT v FROM {table} WHERE k = ?"))
             .await

crates/store/src/backend/mysql/search.rs

@@ -26,7 +26,7 @@ use std::fmt::Write;
 
 impl MysqlStore {
     pub async fn index(&self, documents: Vec<IndexDocument>) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let mut tx_opts = TxOpts::default();
         tx_opts
             .with_consistent_snapshot(false)
@@ -96,7 +96,7 @@ impl MysqlStore {
             build_sort(&mut query, sort);
         }
 
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn.prep(query).await.map_err(into_error)?;
 
         conn.exec::<i64, _, _>(s, params)
@@ -110,7 +110,7 @@ impl MysqlStore {
         let mut query = format!("DELETE FROM {table} ");
         let params = build_filter(&mut query, &filter.filters);
 
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let s = conn.prep(&query).await.map_err(into_error)?;
 
         match conn.exec_drop(s, params.clone()).await {

crates/store/src/backend/mysql/write.rs

@@ -2,6 +2,8 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
 use super::{DELETE_CHUNK_SIZE, MIN_DELETE_CHUNK_SIZE, MysqlStore, into_error, is_timeout_error};
@@ -29,7 +31,7 @@ impl MysqlStore {
     pub(crate) async fn write(&self, mut batch: Batch<'_>) -> trc::Result<AssignedIds> {
         let start = Instant::now();
         let mut retry_count = 0;
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
 
         loop {
             let err = match self.write_trx(&mut conn, &mut batch).await {
@@ -382,7 +384,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn purge_store(&self) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         for subspace in [SUBSPACE_QUOTA, SUBSPACE_COUNTER, SUBSPACE_IN_MEMORY_COUNTER] {
             purge_table(&mut conn, char::from(subspace)).await?;
         }
@@ -391,7 +393,7 @@ impl MysqlStore {
     }
 
     pub(crate) async fn delete_range(&self, from: impl Key, to: impl Key) -> trc::Result<()> {
-        let mut conn = self.conn_pool.get_conn().await.map_err(into_error)?;
+        let mut conn = self.conn().await?;
         let table = char::from(from.subspace());
         let mut from = from.serialize(0);
         let to = to.serialize(0);