From 7e8551e8ea40c92361a1e961e5f8fb1a82f50d75 Mon Sep 17 00:00:00 2001
From: "codeflash-ai[bot]"
 <148906541+codeflash-ai[bot]@users.noreply.github.com>
Date: Thu, 27 Nov 2025 10:09:28 +0000
Subject: [PATCH] Optimize get_dependency_query_params
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The optimization implements **function-level caching for the expensive `get_dependant()` call**. The key insight is that `get_dependant(path="", call=dependency)` performs complex introspection on the dependency callable, but this result is deterministic and can be cached.

**Key changes:**
- Added a function attribute `_dependant_cache` dictionary to cache `get_dependant()` results keyed by the dependency callable
- Cache check before calling `get_dependant()`, only computing when not cached
- Cache storage after computation for future calls

**Why this speeds up the code:**
The line profiler shows `get_dependant()` consumes 52.1% of execution time in the original code (24.9ms out of 47.8ms total). In the optimized version, this drops to 49.6% but with fewer actual calls (26 vs 29 hits), indicating cache hits are avoiding expensive computations. The per-hit cost remains similar (~860μs), confirming the optimization works by reducing call frequency rather than making individual calls faster.

**Performance impact based on usage patterns:**
From the function references, this function is called in two key scenarios:
1. `deserialize_query_params()` - single dependency processing
2. `extract_query_params()` - **iterating over multiple dependencies in a loop**

The loop usage in `extract_query_params()` makes this optimization particularly valuable, as the same dependencies are likely processed repeatedly across requests. The test results show consistent 1-5% improvements across various parameter scenarios, with larger gains for complex dependencies.

**Best performance gains occur when:**
- The same dependency callable is processed multiple times (common in web request handling)
- Dependencies have complex signatures requiring expensive introspection
- Applications process many similar requests with the same endpoint dependencies
---
 src/titiler/core/titiler/core/utils.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/titiler/core/titiler/core/utils.py b/src/titiler/core/titiler/core/utils.py
index 0f7310ef8..4cec23ad1 100644
--- a/src/titiler/core/titiler/core/utils.py
+++ b/src/titiler/core/titiler/core/utils.py
@@ -162,7 +162,15 @@ def get_dependency_query_params(
 
     Important: We assume the `callable` in not a co-routine.
     """
-    dep = get_dependant(path="", call=dependency)
+    cache = getattr(get_dependency_query_params, "_dependant_cache", None)
+    if cache is None:
+        cache = {}
+        setattr(get_dependency_query_params, "_dependant_cache", cache)
+
+    dep = cache.get(dependency)
+    if dep is None:
+        dep = get_dependant(path="", call=dependency)
+        cache[dependency] = dep
 
     qp = (
         QueryParams(urlencode(params, doseq=True))