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src/sydra/compat/stats.zig

Purpose​

Provides simple, process-wide counters used by the Postgres-compatibility translator/pgwire surfaces.

The counters are atomic so they can be incremented from multiple threads.

Used by​

Public API​

pub const Snapshot​

A copyable struct representing counter values at a point in time:

  • translations: u64
  • fallbacks: u64
  • cache_hits: u64

pub const Stats = struct { ... }​

Fields​

  • translation_count: std.atomic.Value(u64)
  • fallback_count: std.atomic.Value(u64)
  • cache_hit_count: std.atomic.Value(u64)

All counters use .seq_cst operations.

Stats struct + helpers (excerpt)
pub const Stats = struct {
    translation_count: std.atomic.Value(u64) = std.atomic.Value(u64).init(0),
    fallback_count: std.atomic.Value(u64) = std.atomic.Value(u64).init(0),
    cache_hit_count: std.atomic.Value(u64) = std.atomic.Value(u64).init(0),

    pub fn noteTranslation(self: *Stats) void {
        _ = self.translation_count.fetchAdd(1, .seq_cst);
    }

    pub fn snapshot(self: *Stats) Snapshot {
        return .{
            .translations = self.translation_count.load(.seq_cst),
            .fallbacks = self.fallback_count.load(.seq_cst),
            .cache_hits = self.cache_hit_count.load(.seq_cst),
        };
    }
};

Counter methods​

  • pub fn noteTranslation(self: *Stats) void
  • pub fn noteFallback(self: *Stats) void
  • pub fn noteCacheHit(self: *Stats) void

Each increments its corresponding atomic counter.

Snapshot + reset​

  • pub fn snapshot(self: *Stats) Snapshot
    • Loads all counters and returns a Snapshot.
  • pub fn reset(self: *Stats) void
    • Stores 0 into all counters.

pub fn global() *Stats​

Returns a pointer to a file-scoped global_stats instance.

pub fn formatSnapshot(snapshot: Snapshot, writer) !void​

Formats snapshot fields in a single line:

translations=123 fallbacks=4 cache_hits=99