From 4c0445540381de0d45a69630ad3e287bd7d1e5fb Mon Sep 17 00:00:00 2001
From: obdev <obdev@oceanbase.com>
Date: Sun, 11 Jul 2021 21:15:12 +0800
Subject: [PATCH] fix collation free compare with rowkey helper

---
 src/storage/ob_sstable_rowkey_helper.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/storage/ob_sstable_rowkey_helper.cpp b/src/storage/ob_sstable_rowkey_helper.cpp
index b6b7a543f8..06dab25e78 100644
--- a/src/storage/ob_sstable_rowkey_helper.cpp
+++ b/src/storage/ob_sstable_rowkey_helper.cpp
@@ -120,7 +120,12 @@ int ObRowkeyObjComparer::sstable_oracle_collation_free_cmp_func(
         // int32_t is always capable of stroing the max lenth of varchar or char
         for (int32_t i = 0; i < left_len; ++i) {
           if (*(uptr + i) != ' ') {
-            cmp = lhs_len > cmp_len ? ObObjCmpFuncs::CR_GT : ObObjCmpFuncs::CR_LT;
+            // mysql特殊行为：a\1 < a，但ab > a
+            if (*(uptr + i) < ' ') {
+              cmp = lhs_len > cmp_len ? ObObjCmpFuncs::CR_LT : ObObjCmpFuncs::CR_GT;
+            } else {
+              cmp = lhs_len > cmp_len ? ObObjCmpFuncs::CR_GT : ObObjCmpFuncs::CR_LT;
+            }
             break;
           }
         }
-- 
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