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Add rel_size_replica_cache (#11889)

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## Problem

See 
Discussion:
https://neondb.slack.com/archives/C033RQ5SPDH/p1746645666075799
Issue: https://github.com/neondatabase/cloud/issues/28609

Relation size cache is not correctly updated at PS in case of replicas.

## Summary of changes

1. Have two caches for relation size in timeline:
`rel_size_primary_cache` and `rel_size_replica_cache`.
2. `rel_size_primary_cache` is actually what we have now. The only
difference is that it is not updated in `get_rel_size`, only by WAL
ingestion
3. `rel_size_replica_cache` has limited size (LruCache) and it's key is
`(Lsn,RelTag)` . It is updated in `get_rel_size`. Only strict LSN
matches are accepted as cache hit.

---------

Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
This commit is contained in:
Konstantin Knizhnik
2025-05-20 18:38:27 +03:00
committed by GitHub
parent 568779fa8a
commit 2e3dc9a8c2
13 changed files with 395 additions and 148 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
libs/pageserver_api/src/config.rs
View File

@@ -491,6 +491,8 @@ pub struct TenantConfigToml {
/// Tenant level performance sampling ratio override. Controls the ratio of get page requests
/// that will get perf sampling for the tenant.
pub sampling_ratio: Option<Ratio>,
/// Capacity of relsize snapshot cache (used by replicas).
pub relsize_snapshot_cache_capacity: usize,
}
pub mod defaults {
@@ -730,6 +732,7 @@ pub mod tenant_conf_defaults {
pub const DEFAULT_GC_COMPACTION_VERIFICATION: bool = true;
pub const DEFAULT_GC_COMPACTION_INITIAL_THRESHOLD_KB: u64 = 5 * 1024 * 1024; // 5GB
pub const DEFAULT_GC_COMPACTION_RATIO_PERCENT: u64 = 100;
pub const DEFAULT_RELSIZE_SNAPSHOT_CACHE_CAPACITY: usize = 1000;
}
impl Default for TenantConfigToml {
@@ -787,6 +790,7 @@ impl Default for TenantConfigToml {
gc_compaction_initial_threshold_kb: DEFAULT_GC_COMPACTION_INITIAL_THRESHOLD_KB,
gc_compaction_ratio_percent: DEFAULT_GC_COMPACTION_RATIO_PERCENT,
sampling_ratio: None,
relsize_snapshot_cache_capacity: DEFAULT_RELSIZE_SNAPSHOT_CACHE_CAPACITY,
}
}
}

13
libs/pageserver_api/src/models.rs
View File

@@ -630,6 +630,8 @@ pub struct TenantConfigPatch {
pub gc_compaction_ratio_percent: FieldPatch<u64>,
#[serde(skip_serializing_if = "FieldPatch::is_noop")]
pub sampling_ratio: FieldPatch<Option<Ratio>>,
#[serde(skip_serializing_if = "FieldPatch::is_noop")]
pub relsize_snapshot_cache_capacity: FieldPatch<usize>,
}
/// Like [`crate::config::TenantConfigToml`], but preserves the information
@@ -759,6 +761,9 @@ pub struct TenantConfig {
#[serde(skip_serializing_if = "Option::is_none")]
pub sampling_ratio: Option<Option<Ratio>>,
#[serde(skip_serializing_if = "Option::is_none")]
pub relsize_snapshot_cache_capacity: Option<usize>,
}
impl TenantConfig {
@@ -804,6 +809,7 @@ impl TenantConfig {
mut gc_compaction_initial_threshold_kb,
mut gc_compaction_ratio_percent,
mut sampling_ratio,
mut relsize_snapshot_cache_capacity,
} = self;
patch.checkpoint_distance.apply(&mut checkpoint_distance);
@@ -905,6 +911,9 @@ impl TenantConfig {
.gc_compaction_ratio_percent
.apply(&mut gc_compaction_ratio_percent);
patch.sampling_ratio.apply(&mut sampling_ratio);
patch
.relsize_snapshot_cache_capacity
.apply(&mut relsize_snapshot_cache_capacity);
Ok(Self {
checkpoint_distance,
@@ -944,6 +953,7 @@ impl TenantConfig {
gc_compaction_initial_threshold_kb,
gc_compaction_ratio_percent,
sampling_ratio,
relsize_snapshot_cache_capacity,
})
}
@@ -1052,6 +1062,9 @@ impl TenantConfig {
.gc_compaction_ratio_percent
.unwrap_or(global_conf.gc_compaction_ratio_percent),
sampling_ratio: self.sampling_ratio.unwrap_or(global_conf.sampling_ratio),
relsize_snapshot_cache_capacity: self
.relsize_snapshot_cache_capacity
.unwrap_or(global_conf.relsize_snapshot_cache_capacity),
}
}
}