feat(pageserver): store reldir in sparse keyspace

Signed-off-by: Alex Chi Z <[email protected]>

libs/pageserver_api/src/config.rs

@@ -341,7 +341,7 @@ pub struct TenantConfigToml {
 
     /// Enable rel_size_v2 for this tenant. Once enabled, the tenant will persist this information into
     /// `index_part.json`, and it cannot be reversed.
-    pub rel_size_v2_enabled: Option<bool>,
+    pub rel_size_v2_enabled: bool,
 
     // gc-compaction related configs
     /// Enable automatic gc-compaction trigger on this tenant.
@@ -609,7 +609,7 @@ impl Default for TenantConfigToml {
             lsn_lease_length_for_ts: LsnLease::DEFAULT_LENGTH_FOR_TS,
             timeline_offloading: false,
             wal_receiver_protocol_override: None,
-            rel_size_v2_enabled: None,
+            rel_size_v2_enabled: true, // TODO: before merge the pull request set it to false
             gc_compaction_enabled: DEFAULT_GC_COMPACTION_ENABLED,
             gc_compaction_initial_threshold_kb: DEFAULT_GC_COMPACTION_INITIAL_THRESHOLD_KB,
             gc_compaction_ratio_percent: DEFAULT_GC_COMPACTION_RATIO_PERCENT,

libs/pageserver_api/src/key.rs

@@ -1,10 +1,12 @@
 use anyhow::{bail, Result};
 use byteorder::{ByteOrder, BE};
+use bytes::Bytes;
 use postgres_ffi::relfile_utils::{FSM_FORKNUM, VISIBILITYMAP_FORKNUM};
 use postgres_ffi::Oid;
 use postgres_ffi::RepOriginId;
 use serde::{Deserialize, Serialize};
 use std::{fmt, ops::Range};
+use utils::const_assert;
 
 use crate::reltag::{BlockNumber, RelTag, SlruKind};
 
@@ -49,6 +51,18 @@ pub const AUX_KEY_PREFIX: u8 = 0x62;
 /// The key prefix of ReplOrigin keys.
 pub const REPL_ORIGIN_KEY_PREFIX: u8 = 0x63;
 
+/// The key prefix of db directory keys.
+pub const DB_DIR_KEY_PREFIX: u8 = 0x64;
+
+/// The key prefix of rel directory keys.
+pub const REL_DIR_KEY_PREFIX: u8 = 0x65;
+
+/// The value of the rel directory keys that indicates the existence of a relation.
+pub const REL_EXISTS_MARKER: Bytes = Bytes::from_static(b"r");
+
+/// A tombstone in the sparse keyspace, which is an empty buffer.
+pub const SPARSE_TOMBSTONE_MARKER: Bytes = Bytes::from_static(b"");
+
 /// Check if the key falls in the range of metadata keys.
 pub const fn is_metadata_key_slice(key: &[u8]) -> bool {
     key[0] >= METADATA_KEY_BEGIN_PREFIX && key[0] < METADATA_KEY_END_PREFIX
@@ -110,6 +124,24 @@ impl Key {
         }
     }
 
+    pub fn rel_dir_sparse_key_range() -> Range<Self> {
+        Key {
+            field1: REL_DIR_KEY_PREFIX,
+            field2: 0,
+            field3: 0,
+            field4: 0,
+            field5: 0,
+            field6: 0,
+        }..Key {
+            field1: REL_DIR_KEY_PREFIX + 1,
+            field2: 0,
+            field3: 0,
+            field4: 0,
+            field5: 0,
+            field6: 0,
+        }
+    }
+
     /// This function checks more extensively what keys we can take on the write path.
     /// If a key beginning with 00 does not have a global/default tablespace OID, it
     /// will be rejected on the write path.
@@ -440,6 +472,36 @@ pub fn rel_dir_to_key(spcnode: Oid, dbnode: Oid) -> Key {
     }
 }
 
+#[inline(always)]
+pub fn rel_tag_sparse_key(spcnode: Oid, dbnode: Oid, relnode: Oid, forknum: u8) -> Key {
+    Key {
+        field1: REL_DIR_KEY_PREFIX,
+        field2: spcnode,
+        field3: dbnode,
+        field4: relnode,
+        field5: forknum,
+        field6: 1,
+    }
+}
+
+pub fn rel_tag_sparse_key_range(spcnode: Oid, dbnode: Oid) -> Range<Key> {
+    Key {
+        field1: REL_DIR_KEY_PREFIX,
+        field2: spcnode,
+        field3: dbnode,
+        field4: 0,
+        field5: 0,
+        field6: 0,
+    }..Key {
+        field1: REL_DIR_KEY_PREFIX,
+        field2: spcnode,
+        field3: dbnode,
+        field4: u32::MAX,
+        field5: u8::MAX,
+        field6: u32::MAX,
+    } // it's fine to exclude the last key b/c we only use field6 == 1
+}
+
 #[inline(always)]
 pub fn rel_block_to_key(rel: RelTag, blknum: BlockNumber) -> Key {
     Key {
@@ -734,9 +796,9 @@ impl Key {
         self.field1 == RELATION_SIZE_PREFIX
     }
 
-    pub fn sparse_non_inherited_keyspace() -> Range<Key> {
+    pub const fn sparse_non_inherited_keyspace() -> Range<Key> {
         // The two keys are adjacent; if we will have non-adjancent keys in the future, we should return a keyspace
-        debug_assert_eq!(AUX_KEY_PREFIX + 1, REPL_ORIGIN_KEY_PREFIX);
+        const_assert!(AUX_KEY_PREFIX + 1 == REPL_ORIGIN_KEY_PREFIX);
         Key {
             field1: AUX_KEY_PREFIX,
             field2: 0,