Check for pitr_interval == 0

pageserver/src/consumption_metrics/metrics.rs

@@ -1,5 +1,5 @@
 use std::sync::Arc;
-use std::time::SystemTime;
+use std::time::{Duration, SystemTime};
 
 use chrono::{DateTime, Utc};
 use consumption_metrics::EventType;
@@ -10,7 +10,6 @@ use utils::lsn::Lsn;
 use super::{Cache, NewRawMetric};
 use crate::context::RequestContext;
 use crate::tenant::mgr::TenantManager;
-use crate::tenant::timeline::GcCutoffs;
 use crate::tenant::timeline::logical_size::CurrentLogicalSize;
 
 /// Name of the metric, used by `MetricsKey` factory methods and `deserialize_cached_events`
@@ -390,7 +389,8 @@ struct TimelineSnapshot {
     loaded_at: (Lsn, SystemTime),
     last_record_lsn: Lsn,
     current_exact_logical_size: Option<u64>,
-    gc_cutoffs: GcCutoffs,
+    /// The PITR cutoff LSN. None if PITR is disabled.
+    pitr_cutoff: Option<Lsn>,
 }
 
 impl TimelineSnapshot {
@@ -410,7 +410,8 @@ impl TimelineSnapshot {
         } else {
             let loaded_at = t.loaded_at;
             let last_record_lsn = t.get_last_record_lsn();
-            let gc_cutoffs = t.gc_info.read().unwrap().cutoffs; // NB: assume periodically updated
+            let pitr_cutoff = (t.get_pitr_interval() != Duration::ZERO)
+                .then(|| t.gc_info.read().unwrap().cutoffs.time);
 
             let current_exact_logical_size = {
                 let span = tracing::info_span!("collect_metrics_iteration", tenant_id = %t.tenant_shard_id.tenant_id, timeline_id = %t.timeline_id);
@@ -431,7 +432,7 @@ impl TimelineSnapshot {
                 loaded_at,
                 last_record_lsn,
                 current_exact_logical_size,
-                gc_cutoffs,
+                pitr_cutoff,
             }))
         }
     }
@@ -505,7 +506,10 @@ impl TimelineSnapshot {
         // entire history. Also verify that it's okay for this to regress on restart, unlike e.g.
         // written_size above.
         let pitr_history_size_key = MetricsKey::pitr_history_size(tenant_id, timeline_id);
-        let pitr_history_size = self.last_record_lsn.saturating_sub(self.gc_cutoffs.time);
+        let pitr_history_size = self
+            .pitr_cutoff
+            .map(|pitr| self.last_record_lsn.saturating_sub(pitr))
+            .unwrap_or_default();
         metrics.push(pitr_history_size_key.at(now, pitr_history_size.into()));
 
         {

pageserver/src/consumption_metrics/metrics/tests.rs

@@ -20,10 +20,7 @@ fn startup_collected_timeline_metrics_before_advancing() {
         loaded_at: (disk_consistent_lsn, SystemTime::now()),
         last_record_lsn: disk_consistent_lsn,
         current_exact_logical_size: Some(logical_size),
-        gc_cutoffs: GcCutoffs {
-            space: Lsn::INVALID,
-            time: pitr_cutoff,
-        },
+        pitr_cutoff: Some(pitr_cutoff),
     };
 
     let now = DateTime::<Utc>::from(SystemTime::now());
@@ -70,10 +67,7 @@ fn startup_collected_timeline_metrics_second_round() {
         loaded_at: (disk_consistent_lsn, init),
         last_record_lsn: disk_consistent_lsn,
         current_exact_logical_size: Some(logical_size),
-        gc_cutoffs: GcCutoffs {
-            space: Lsn::INVALID,
-            time: pitr_cutoff,
-        },
+        pitr_cutoff: Some(pitr_cutoff),
     };
 
     snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
@@ -122,10 +116,7 @@ fn startup_collected_timeline_metrics_nth_round_at_same_lsn() {
         loaded_at: (disk_consistent_lsn, init),
         last_record_lsn: disk_consistent_lsn,
         current_exact_logical_size: Some(logical_size),
-        gc_cutoffs: GcCutoffs {
-            space: Lsn::INVALID,
-            time: pitr_cutoff,
-        },
+        pitr_cutoff: Some(pitr_cutoff),
     };
 
     snap.to_metrics(tenant_id, timeline_id, now, &mut metrics, &cache);
@@ -165,7 +156,7 @@ fn post_restart_written_sizes_with_rolled_back_last_record_lsn() {
         loaded_at: (Lsn(50), at_restart),
         last_record_lsn: Lsn(50),
         current_exact_logical_size: None,
-        gc_cutoffs: GcCutoffs::default(),
+        pitr_cutoff: Some(Lsn(0)),
     };
 
     let mut cache = HashMap::from([
@@ -229,7 +220,7 @@ fn post_restart_current_exact_logical_size_uses_cached() {
         loaded_at: (Lsn(50), at_restart),
         last_record_lsn: Lsn(50),
         current_exact_logical_size: None,
-        gc_cutoffs: GcCutoffs::default(),
+        pitr_cutoff: None,
     };
 
     let cache = HashMap::from([MetricsKey::timeline_logical_size(tenant_id, timeline_id)

pageserver/src/tenant.rs

@@ -4718,7 +4718,7 @@ impl TenantShard {
                 // - this timeline was created while we were finding cutoffs
                 // - lsn for timestamp search fails for this timeline repeatedly
                 if let Some(cutoffs) = gc_cutoffs.get(&timeline.timeline_id) {
-                    let original_cutoffs = target.cutoffs;
+                    let original_cutoffs = target.cutoffs.clone();
                     // GC cutoffs should never go back
                     target.cutoffs = GcCutoffs {
                         space: Lsn(cutoffs.space.0.max(original_cutoffs.space.0)),

pageserver/src/tenant/timeline.rs

@@ -537,7 +537,7 @@ impl GcInfo {
 /// The `GcInfo` component describing which Lsns need to be retained.  Functionally, this
 /// is a single number (the oldest LSN which we must retain), but it internally distinguishes
 /// between time-based and space-based retention for observability and consumption metrics purposes.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub(crate) struct GcCutoffs {
     /// Calculated from the [`pageserver_api::models::TenantConfig::gc_horizon`], this LSN indicates how much
     /// history we must keep to retain a specified number of bytes of WAL.
@@ -2543,6 +2543,13 @@ impl Timeline {
             .unwrap_or(self.conf.default_tenant_conf.checkpoint_timeout)
     }
 
+    pub(crate) fn get_pitr_interval(&self) -> Duration {
+        let tenant_conf = &self.tenant_conf.load().tenant_conf;
+        tenant_conf
+            .pitr_interval
+            .unwrap_or(self.conf.default_tenant_conf.pitr_interval)
+    }
+
     fn get_compaction_period(&self) -> Duration {
         let tenant_conf = self.tenant_conf.load().tenant_conf.clone();
         tenant_conf