diff --git a/ChangeLog b/ChangeLog
index 2bb4e08..ae26ad8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -201,6 +201,10 @@ PCRE2_EXTRA_MATCH_WORD, and PCRE2_EXTRA_MATCH_LINE. This fixes two bugs:
 44. Added configuration options for the SELinux compatible execmem allocator in
 JIT.
 
+45. Increased the limit for searching for a "must be present" code unit in 
+subjects from 1000 to 2000 for 8-bit searches, since they use memchr() and are 
+much faster.
+
 
 Version 10.23 14-February-2017
 ------------------------------
diff --git a/src/pcre2_internal.h b/src/pcre2_internal.h
index 02e1b9f..bc52b9a 100644
--- a/src/pcre2_internal.h
+++ b/src/pcre2_internal.h
@@ -557,9 +557,14 @@ enum { PCRE2_MATCHEDBY_INTERPRETER,     /* pcre2_match() */
 #define MAGIC_NUMBER  0x50435245UL   /* 'PCRE' */
 
 /* The maximum remaining length of subject we are prepared to search for a
-req_unit match. */
+req_unit match. In 8-bit mode, memchr() is used and is much faster than the 
+search loop that has to be used in 16-bit and 32-bit modes. */
 
+#if PCRE2_CODE_UNIT_WIDTH == 8
+#define REQ_CU_MAX 2000
+#else
 #define REQ_CU_MAX 1000
+#endif
 
 /* Offsets for the bitmap tables in the cbits set of tables. Each table
 contains a set of bits for a class map. Some classes are built by combining