From 32535ef4ed56a8841471579341abd3f19399fc6d Mon Sep 17 00:00:00 2001
From: pedrocarlo <pedro.muniz.carlo@gmail.com>
Date: Thu, 6 Nov 2025 17:30:15 -0300
Subject: [PATCH] only emit affinity check on index seek + check if affinity is
 necessary at all

---
 core/translate/main_loop.rs             | 22 ++++++++++++++++------
 core/translate/optimizer/constraints.rs |  7 +++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/core/translate/main_loop.rs b/core/translate/main_loop.rs
index fd943a18f..14424ea7f 100644
--- a/core/translate/main_loop.rs
+++ b/core/translate/main_loop.rs
@@ -27,6 +27,7 @@ use crate::{
     },
     types::SeekOp,
     vdbe::{
+        affinity,
         builder::{CursorKey, CursorType, ProgramBuilder},
         insn::{CmpInsFlags, IdxInsertFlags, Insn},
         BranchOffset, CursorID,
@@ -1376,14 +1377,23 @@ fn emit_seek(
     }
     let num_regs = seek_def.size(&seek_def.start);
 
-    program.emit_insn(Insn::Affinity {
-        start_reg,
-        count: std::num::NonZeroUsize::new(num_regs).unwrap(),
-        affinities: seek_def
+    if is_index {
+        let affinities: String = seek_def
             .iter_affinity(&seek_def.start)
             .map(|affinity| affinity.aff_mask())
-            .collect(),
-    });
+            .collect();
+        if affinities.chars().any(|c| c != affinity::SQLITE_AFF_NONE) {
+            program.emit_insn(Insn::Affinity {
+                start_reg,
+                count: std::num::NonZeroUsize::new(num_regs).unwrap(),
+                affinities: seek_def
+                    .iter_affinity(&seek_def.start)
+                    .map(|affinity| affinity.aff_mask())
+                    .collect(),
+            });
+        }
+    }
+
     match seek_def.start.op {
         SeekOp::GE { eq_only } => program.emit_insn(Insn::SeekGE {
             is_index,
diff --git a/core/translate/optimizer/constraints.rs b/core/translate/optimizer/constraints.rs
index 80afeac68..4e6b6bbd0 100644
--- a/core/translate/optimizer/constraints.rs
+++ b/core/translate/optimizer/constraints.rs
@@ -83,9 +83,16 @@ impl Constraint {
         if op.is_comparison() {
             affinity = comparison_affinity(lhs, rhs, referenced_tables);
         }
+
         if side == BinaryExprSide::Lhs {
+            if affinity.expr_needs_no_affinity_change(lhs) {
+                affinity = Affinity::Blob;
+            }
             (self.operator, lhs.clone(), affinity)
         } else {
+            if affinity.expr_needs_no_affinity_change(rhs) {
+                affinity = Affinity::Blob;
+            }
             (self.operator, rhs.clone(), affinity)
         }
     }