Skip to content

Optimize RedisValue / Equals #3116

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
pairbit wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Optimize RedisValue / Equals #3116

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
95f2658
RawStringEquals, GetHashCodeUtf8, fix buf StartsWith(Span) if not ASCII
pairbit Jun 26, 2026
c24cdd2
undo GetHashCode
pairbit Jun 26, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
63 changes: 53 additions & 10 deletions src/StackExchange.Redis/RedisValue.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -469,6 +469,18 @@ internal string RawString()
// memory / short-blob / sequence) compare by raw bytes in any combination
if (IsBlob(xType) && IsBlob(yType)) return BlobSequenceEqual(x, y);

switch (xType)
{
case StorageType.Sequence when yType == StorageType.String:
return y.RawStringEquals(x.RawSequence());
case StorageType.String when yType == StorageType.Sequence:
return x.RawStringEquals(y.RawSequence());
case StorageType.ByteArray or StorageType.MemoryManager or StorageType.ShortBlob when yType == StorageType.String:
return y.RawStringEquals(x.UnsafeRawSpan(out _));
case StorageType.String when yType is StorageType.ByteArray or StorageType.MemoryManager or StorageType.ShortBlob:
return x.RawStringEquals(y.UnsafeRawSpan(out _));
}

// otherwise (anything involving a string), compare as strings
return (string?)x == (string?)y;
}
Expand Down Expand Up @@ -559,12 +571,15 @@ internal static unsafe bool Equals(byte[]? x, byte[]? y)
return true;
}

private static int AddHashCode(ReadOnlySpan<byte> span, int acc)
// used by RedisKey, whose equality is byte-based (unlike RedisValue, which treats non-numeric
// buffers as strings - see GetHashCode(RedisValue))
internal static int GetHashCode(ReadOnlySpan<byte> span)
{
unchecked
{
int len = span.Length;
Debug.Assert(len > 0);
if (len == 0) return 0;
var acc = 728271210;

var span64 = MemoryMarshal.Cast<byte, long>(span);
for (int i = 0; i < span64.Length; i++)
Expand All @@ -582,16 +597,43 @@ private static int AddHashCode(ReadOnlySpan<byte> span, int acc)
}
}

// used by RedisKey, whose equality is byte-based (unlike RedisValue, which treats non-numeric
// buffers as strings - see GetHashCode(RedisValue))
internal static int GetHashCode(ReadOnlySpan<byte> span)
{
if (span.Length == 0) return 0;
private bool RawStringEquals(ReadOnlySpan<byte> span)
{
string s = RawString();
var length = s.Length;
if (length == 0) return span.IsEmpty;
var maxChars = Encoding.UTF8.GetMaxCharCount(span.Length);
if (length > maxChars) return false;

byte[]? leased = null;
var maxBytes = Encoding.UTF8.GetMaxByteCount(length);
Span<byte> bytes = maxBytes <= StackByteLimit ? stackalloc byte[maxBytes] : (leased = ArrayPool<byte>.Shared.Rent(maxBytes));
var written = Encoding.UTF8.GetBytes(s, bytes);
var result = span.SequenceEqual(bytes.Slice(0, written));
if (leased is not null) ArrayPool<byte>.Shared.Return(leased);
return result;
}

return AddHashCode(span, HashCodeStart);
private bool RawStringEquals(ReadOnlySequence<byte> seq)
{
string s = RawString();
var length = s.Length;
var seqLength = seq.Length;
if (length == 0) return seqLength == 0;
if (seq.Length > int.MaxValue) return false;
var maxChars = Encoding.UTF8.GetMaxCharCount(checked((int)seqLength));
if (length > maxChars) return false;

byte[]? leased = null;
var maxBytes = Encoding.UTF8.GetMaxByteCount(length);
Span<byte> bytes = maxBytes <= StackByteLimit ? stackalloc byte[maxBytes] : (leased = ArrayPool<byte>.Shared.Rent(maxBytes));
var written = Encoding.UTF8.GetBytes(s, bytes);
var result = seq.SequenceEqual(bytes.Slice(0, written));
if (leased is not null) ArrayPool<byte>.Shared.Return(leased);
return result;
}

private const int HashCodeStart = 728271210;
private const int StackByteLimit = 512;

internal void AssertNotNull()
{
Expand Down Expand Up @@ -1791,7 +1833,8 @@ public bool StartsWith(ReadOnlySpan<byte> value)
return buffer.Slice(0, len).StartsWith(value);
case StorageType.String:
var s = RawString().AsSpan();
if (s.Length < value.Length) return false; // not enough characters to match
// BUG if Not ASCII
// if (s.Length < value.Length) return false; // not enough characters to match
if (s.Length > value.Length) s = s.Slice(0, value.Length); // only need to match the prefix
var maxBytes = Encoding.UTF8.GetMaxByteCount(s.Length);
byte[]? lease = null;
Expand Down
Loading