Improve synthetic_size json output:

- add new fields 'parent_lsn' and 'wal_from_parent' to segments;
- output 'timeline_inputs' lsns as u64 to be consistent with other places

libs/tenant_size_model/src/lib.rs

@@ -37,10 +37,15 @@ pub struct Segment {
     /// LSN at this point
     pub lsn: u64,
 
+    pub parent_lsn: Option<u64>,
+
+    pub wal_from_parent: Option<u64>,
+
     /// Logical size at this node, if known.
     pub size: Option<u64>,
 
     /// If true, the segment from parent to this node is needed by `retention_period`
+    /// if wal_from_parent is needed by `retention_period`?
     pub needed: bool,
 }
 

libs/tenant_size_model/tests/tests.rs

@@ -17,6 +17,8 @@ impl ScenarioBuilder {
         let init_segment = Segment {
             parent: None,
             lsn: 0,
+            parent_lsn: None,
+            wal_from_parent: None,
             size: Some(0),
             needed: false, // determined later
         };
@@ -36,6 +38,8 @@ impl ScenarioBuilder {
         let newseg = Segment {
             parent: Some(lastseg_id),
             lsn: lastseg.lsn + lsn_bytes,
+            parent_lsn: Some(lastseg.lsn),
+            wal_from_parent: Some(lsn_bytes),
             size: Some((lastseg.size.unwrap() as i64 + size_bytes) as u64),
             needed: false,
         };

pageserver/src/tenant/size.rs

@@ -85,23 +85,16 @@ pub struct TimelineInputs {
     #[serde_as(as = "Option<serde_with::DisplayFromStr>")]
     pub ancestor_id: Option<TimelineId>,
 
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     ancestor_lsn: Lsn,
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     last_record: Lsn,
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     latest_gc_cutoff: Lsn,
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     horizon_cutoff: Lsn,
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     pitr_cutoff: Lsn,
 
     /// Cutoff point based on GC settings
-    #[serde_as(as = "serde_with::DisplayFromStr")]
     next_gc_cutoff: Lsn,
 
     /// Cutoff point calculated from the user-supplied 'max_retention_period'
-    #[serde_as(as = "Option<serde_with::DisplayFromStr>")]
     retention_param_cutoff: Option<Lsn>,
 }
 
@@ -252,6 +245,8 @@ pub(super) async fn gather_inputs(
             segment: Segment {
                 parent: None, // filled in later
                 lsn: branch_start_lsn.0,
+                parent_lsn: None,
+                wal_from_parent: None,
                 size: None, // filled in later
                 needed: branch_start_needed,
             },
@@ -270,6 +265,8 @@ pub(super) async fn gather_inputs(
                 segment: Segment {
                     parent: Some(parent),
                     lsn: lsn.0,
+                    parent_lsn: Some(segments[parent].segment.lsn),
+                    wal_from_parent: Some(lsn.0 - segments[parent].segment.lsn),
                     size: None,
                     needed: lsn > next_gc_cutoff,
                 },
@@ -284,6 +281,8 @@ pub(super) async fn gather_inputs(
             segment: Segment {
                 parent: Some(parent),
                 lsn: last_record_lsn.0,
+                parent_lsn: Some(segments[parent].segment.lsn),
+                wal_from_parent: Some(last_record_lsn.0 - segments[parent].segment.lsn),
                 size: None, // Filled in later, if necessary
                 needed: true,
             },
@@ -613,32 +612,32 @@ fn verify_size_for_multiple_branches() {
   "timeline_inputs": [
     {
       "timeline_id": "20b129c9b50cff7213e6503a31b2a5ce",
-      "ancestor_lsn": "0/18D3D98",
-      "last_record": "0/2230CD0",
-      "latest_gc_cutoff": "0/1698C48",
-      "horizon_cutoff": "0/2210CD0",
-      "pitr_cutoff": "0/2210CD0",
-      "next_gc_cutoff": "0/2210CD0",
+      "ancestor_lsn": 26033560,
+      "last_record": 35851472,
+      "latest_gc_cutoff": 23694408,
+      "horizon_cutoff": 35720400,
+      "pitr_cutoff": 35720400,
+      "next_gc_cutoff": 35720400,
       "retention_param_cutoff": null
     },
     {
       "timeline_id": "454626700469f0a9914949b9d018e876",
-      "ancestor_lsn": "0/176D998",
-      "last_record": "0/1837770",
-      "latest_gc_cutoff": "0/1698C48",
-      "horizon_cutoff": "0/1817770",
-      "pitr_cutoff": "0/1817770",
-      "next_gc_cutoff": "0/1817770",
+      "ancestor_lsn": 24566168,
+      "last_record": 25393008,
+      "latest_gc_cutoff": 23694408,
+      "horizon_cutoff": 25261936,
+      "pitr_cutoff": 25261936,
+      "next_gc_cutoff": 25261936,
       "retention_param_cutoff": null
     },
     {
       "timeline_id": "cb5e3cbe60a4afc00d01880e1a37047f",
-      "ancestor_lsn": "0/0",
-      "last_record": "0/18D3D98",
-      "latest_gc_cutoff": "0/1698C48",
-      "horizon_cutoff": "0/18B3D98",
-      "pitr_cutoff": "0/18B3D98",
-      "next_gc_cutoff": "0/18B3D98",
+      "ancestor_lsn": 0,
+      "last_record": 26033560,
+      "latest_gc_cutoff": 23694408,
+      "horizon_cutoff":25902488,
+      "pitr_cutoff":25902488,
+      "next_gc_cutoff":25902488,
       "retention_param_cutoff": null
     }
   ]
@@ -688,13 +687,13 @@ fn verify_size_for_one_branch() {
   "timeline_inputs": [
     {
       "timeline_id": "f15ae0cf21cce2ba27e4d80c6709a6cd",
-      "ancestor_lsn": "0/0",
-      "last_record": "47/280A5860",
-      "latest_gc_cutoff": "47/240A5860",
-      "horizon_cutoff": "47/240A5860",
-      "pitr_cutoff": "47/240A5860",
-      "next_gc_cutoff": "47/240A5860",
-      "retention_param_cutoff": "0/0"
+      "ancestor_lsn": 0,
+      "last_record": 305547335776,
+      "latest_gc_cutoff": 305614444640,
+      "horizon_cutoff": 305614444640,
+      "pitr_cutoff": 305614444640,
+      "next_gc_cutoff": 305614444640,
+      "retention_param_cutoff": 0
     }
   ]
 }"#;
@@ -707,12 +706,15 @@ fn verify_size_for_one_branch() {
     println!("result: {:?}", serde_json::to_string(&res.segments));
 
     use utils::lsn::Lsn;
-    let latest_gc_cutoff_lsn: Lsn = "47/240A5860".parse().unwrap();
-    let last_lsn: Lsn = "47/280A5860".parse().unwrap();
+    let latest_gc_cutoff_lsn: Lsn = Lsn(305614444640);
+    let last_lsn: Lsn = Lsn(305547335776);
     println!(
-        "latest_gc_cutoff lsn 47/240A5860 is {}, last_lsn lsn 47/280A5860 is {}",
+        "latest_gc_cutoff lsn {} is {}, last_lsn lsn {} is {}",
+        latest_gc_cutoff_lsn,
         u64::from(latest_gc_cutoff_lsn),
+        last_lsn,
         u64::from(last_lsn)
     );
+
     assert_eq!(res.total_size, 220121784320);
 }

test_runner/regress/test_tenant_size.py

@@ -52,12 +52,26 @@ def test_empty_tenant_size(neon_simple_env: NeonEnv, test_output_dir: Path):
     expected_inputs = {
         "segments": [
             {
-                "segment": {"parent": None, "lsn": 23694408, "size": 25362432, "needed": True},
+                "segment": {
+                    "parent": None,
+                    "lsn": 23694408,
+                    "parent_lsn": None,
+                    "wal_from_parent": None,
+                    "size": 25362432,
+                    "needed": True,
+                },
                 "timeline_id": f"{main_timeline_id}",
                 "kind": "BranchStart",
             },
             {
-                "segment": {"parent": 0, "lsn": 23694528, "size": None, "needed": True},
+                "segment": {
+                    "parent": 0,
+                    "lsn": 23694528,
+                    "parent_lsn": 23694408,
+                    "wal_from_parent": 120,
+                    "size": None,
+                    "needed": True,
+                },
                 "timeline_id": f"{main_timeline_id}",
                 "kind": "BranchEnd",
             },
@@ -66,16 +80,17 @@ def test_empty_tenant_size(neon_simple_env: NeonEnv, test_output_dir: Path):
             {
                 "timeline_id": f"{main_timeline_id}",
                 "ancestor_id": None,
-                "ancestor_lsn": "0/0",
-                "last_record": "0/1698CC0",
-                "latest_gc_cutoff": "0/1698C48",
-                "horizon_cutoff": "0/0",
-                "pitr_cutoff": "0/0",
-                "next_gc_cutoff": "0/0",
+                "ancestor_lsn": 0,
+                "last_record": 23694528,
+                "latest_gc_cutoff": 23694408,
+                "horizon_cutoff": 0,
+                "pitr_cutoff": 0,
+                "next_gc_cutoff": 0,
                 "retention_param_cutoff": None,
             }
         ],
     }
+
     expected_inputs = mask_model_inputs(expected_inputs)
     actual_inputs = mask_model_inputs(inputs)
 
@@ -641,7 +656,11 @@ def mask_model_inputs(x):
     if isinstance(x, dict):
         newx = {}
         for k, v in x.items():
-            if k == "size":
+            if (
+                k in ["size", "wal_from_parent", "last_record"]
+                or k.endswith("lsn")
+                or k.endswith("cutoff")
+            ):
                 if v is None or v == 0:
                     # no change
                     newx[k] = v
@@ -649,12 +668,6 @@ def mask_model_inputs(x):
                     newx[k] = "<0"
                 else:
                     newx[k] = ">0"
-            elif k.endswith("lsn") or k.endswith("cutoff") or k == "last_record":
-                if v is None or v == 0 or v == "0/0":
-                    # no change
-                    newx[k] = v
-                else:
-                    newx[k] = "masked"
             else:
                 newx[k] = mask_model_inputs(v)
         return newx