From 47e06a2cc6875b754e80442a034f77211dd7f799 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Wed, 3 Jul 2024 20:05:01 +0200
Subject: [PATCH] page_service: stop exposing `get_last_record_rlsn` (#8244)

Compute doesn't use it, let's eliminate it.

Ref to Slack thread:
https://neondb.slack.com/archives/C033RQ5SPDH/p1719920261995529
---
 pageserver/src/metrics.rs        |  1 -
 pageserver/src/page_service.rs   | 47 --------------------------------
 test_runner/regress/test_auth.py |  2 +-
 3 files changed, 1 insertion(+), 49 deletions(-)

diff --git a/pageserver/src/metrics.rs b/pageserver/src/metrics.rs
index a21d8780cf..87ff8f4d64 100644
--- a/pageserver/src/metrics.rs
+++ b/pageserver/src/metrics.rs
@@ -1452,7 +1452,6 @@ pub(crate) enum ComputeCommandKind {
     PageStreamV2,
     PageStream,
     Basebackup,
-    GetLastRecordRlsn,
     Fullbackup,
     ImportBasebackup,
     ImportWal,
diff --git a/pageserver/src/page_service.rs b/pageserver/src/page_service.rs
index 6ea5f396d0..a440ad6378 100644
--- a/pageserver/src/page_service.rs
+++ b/pageserver/src/page_service.rs
@@ -1656,53 +1656,6 @@ where
             metric_recording.observe(&res);
             res?;
         }
-        // return pair of prev_lsn and last_lsn
-        else if let Some(params) = parts.strip_prefix(&["get_last_record_rlsn"]) {
-            if params.len() != 2 {
-                return Err(QueryError::Other(anyhow::anyhow!(
-                    "invalid param number for get_last_record_rlsn command"
-                )));
-            }
-
-            let tenant_id = TenantId::from_str(params[0])
-                .with_context(|| format!("Failed to parse tenant id from {}", params[0]))?;
-            let timeline_id = TimelineId::from_str(params[1])
-                .with_context(|| format!("Failed to parse timeline id from {}", params[1]))?;
-
-            tracing::Span::current()
-                .record("tenant_id", field::display(tenant_id))
-                .record("timeline_id", field::display(timeline_id));
-
-            self.check_permission(Some(tenant_id))?;
-
-            COMPUTE_COMMANDS_COUNTERS
-                .for_command(ComputeCommandKind::GetLastRecordRlsn)
-                .inc();
-
-            async {
-                let timeline = self
-                    .get_active_tenant_timeline(tenant_id, timeline_id, ShardSelector::Zero)
-                    .await?;
-
-                let end_of_timeline = timeline.get_last_record_rlsn();
-
-                pgb.write_message_noflush(&BeMessage::RowDescription(&[
-                    RowDescriptor::text_col(b"prev_lsn"),
-                    RowDescriptor::text_col(b"last_lsn"),
-                ]))?
-                .write_message_noflush(&BeMessage::DataRow(&[
-                    Some(end_of_timeline.prev.to_string().as_bytes()),
-                    Some(end_of_timeline.last.to_string().as_bytes()),
-                ]))?
-                .write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
-                anyhow::Ok(())
-            }
-            .instrument(info_span!(
-                "handle_get_last_record_lsn",
-                shard_id = tracing::field::Empty
-            ))
-            .await?;
-        }
         // same as basebackup, but result includes relational data as well
         else if let Some(params) = parts.strip_prefix(&["fullbackup"]) {
             if params.len() < 2 {
diff --git a/test_runner/regress/test_auth.py b/test_runner/regress/test_auth.py
index 035ab2796f..922a21a999 100644
--- a/test_runner/regress/test_auth.py
+++ b/test_runner/regress/test_auth.py
@@ -211,7 +211,7 @@ def test_auth_failures(neon_env_builder: NeonEnvBuilder, auth_enabled: bool):
     def check_pageserver(expect_success: bool, **conn_kwargs):
         check_connection(
             env.pageserver,
-            f"get_last_record_rlsn {env.initial_tenant} {timeline_id}",
+            f"show {env.initial_tenant}",
             expect_success,
             **conn_kwargs,
         )