Database connections kept open; a click's wait is measured (#241, #245, #246)

#241: on production, All Subscriptions' query runs in 31 ms, unread oldest-first in 30, the
feed list's count in 5, generic plans included (EXPLAIN ANALYZE, BUFFERS, read only), against
0.3-1.6 s in ipx. A new Postgres connection takes 80-330 ms to open, and a page load asks for
more than are idle: four of six slow loads came as the pool grew (3 to 6, 2 to 6, 3 to 5, 6 to
8), and 20 requests at once took a median 414 ms while the pool grew from 8 to 20. The daemon
and the directory's server now keep their whole pool open (min = max); a command such as `ipx
status`, and the tests, which share the server's 100 connections, open as they need.

#246: the page reports list_shown, the ms from asking for a list to drawing it, with the view
and filter, under the click's trace; background refreshes are not timed. Timings skip report()'s
once-a-minute limit, which is for errors in a loop. A dashboard panel and table, and the prod
check, read it.

#245: the load test's browse scenario subscribes by OPML and leaves the Directory, which is
ipx-directory's since #204, to it.

CLAUDE.md records the owner's leave to EXPLAIN (ANALYZE, BUFFERS) any query on production,
read only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/directory/src/main.rs

@@ -92,7 +92,7 @@ async fn serve(path: &std::path::Path) -> Result<()> {
         .ok()
         .filter(|u| !u.trim().is_empty())
         .with_context(|| format!("{} is not set: the directory needs a database URL", cfg.database_url_env))?;
-    let store = Store::open(&url).await.context("opening the database")?;
+    let store = Store::open(&url, true).await.context("opening the database")?;
     let dir = Directory::new(store, vec![])?;
     let dropped = dir.set_tokens(tokens).await?;
 

crates/directory/src/store.rs

@@ -99,7 +99,7 @@ impl Store {
     pub async fn scratch() -> Self {
         static N: std::sync::atomic::AtomicU32 = std::sync::atomic::AtomicU32::new(0);
         let Some(url) = std::env::var("IPX_TEST_DATABASE_URL").ok().filter(|u| !u.is_empty()) else {
-            return Self::open("sqlite::memory:").await.unwrap();
+            return Self::open("sqlite::memory:", false).await.unwrap();
         };
         let (pid, n) = (std::process::id(), N.fetch_add(1, std::sync::atomic::Ordering::Relaxed));
         // A bare connection: Store::open would make the tables in the public schema, and the
@@ -117,10 +117,11 @@ impl Store {
         let schema = format!("ipxd_{pid}_{n}");
         admin.db.execute_unprepared(&format!("CREATE SCHEMA {schema}")).await.unwrap();
         let sep = if url.contains('?') { '&' } else { '?' };
-        Self::open(&format!("{url}{sep}options=-c%20search_path%3D{schema}%20-c%20client_min_messages%3Dwarning")).await.unwrap()
+        Self::open(&format!("{url}{sep}options=-c%20search_path%3D{schema}%20-c%20client_min_messages%3Dwarning"), false).await.unwrap()
     }
 
-    pub async fn open(url: &str) -> Result<Self> {
+    /// `keep_open` for the server, which keeps its whole pool connected.
+    pub async fn open(url: &str, keep_open: bool) -> Result<Self> {
         let mut url = url.to_owned();
         if url.starts_with("postgres") && !url.contains("options=") {
             // Postgres sends a notice for every CREATE ... IF NOT EXISTS on something that exists;
@@ -134,6 +135,11 @@ impl Store {
         if url.contains(":memory:") {
             opts.max_connections(1);
         }
+        // The server keeps every connection open, as ipx's daemon does: a Postgres connection takes
+        // 80-330 ms to open (#241). Not a test, which would hold ten for one question.
+        if keep_open && url.starts_with("postgres") {
+            opts.max_connections(10).min_connections(10);
+        }
         let db = sea_orm::Database::connect(opts).await?;
         for sql in SCHEMA {
             db.execute_unprepared(sql).await?;