lib/dfa.c: increase the transitions table max size

Resolves: RHEL-17133

sed-regexp-cache-size.patch

@@ -0,0 +1,25 @@
+From 2d1641d76c0254e3c95f461d9a0fd080e0f29c3c Mon Sep 17 00:00:00 2001
+From: Jakub Martisko <jamartis@redhat.com>
+Date: Fri, 23 Jan 2026 13:21:41 +0100
+Subject: [PATCH] increase tr count
+
+---
+ lib/dfa.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/dfa.c b/lib/dfa.c
+index 0b694e1..d76e9ec 100644
+--- a/lib/dfa.c
++++ b/lib/dfa.c
+@@ -354,7 +354,7 @@ typedef struct
+ 
+ /* Maximum for any transition table count.  This should be at least 3,
+    for the initial state setup.  */
+-enum { MAX_TRCOUNT = 1024 };
++enum { MAX_TRCOUNT = 2048 };
+ 
+ /* A bracket operator.
+    e.g., [a-c], [[:alpha:]], etc.  */
+-- 
+2.52.0
+

sed.spec

@@ -12,6 +12,8 @@ Source1: http://sed.sourceforge.net/sedfaq.txt
 Patch0: sed-4.2.2-binary_copy_args.patch
 Patch2: sed-fuse.patch
 Patch3: sed-selinux-testsuite.patch
+Patch4: sed-regexp-cache-size.patch
+
 BuildRequires: glibc-devel, libselinux-devel, libacl-devel, automake, autoconf
 BuildRequires: perl-Getopt-Long
 Requires(post): /sbin/install-info
@@ -34,6 +36,7 @@ specified in a script file or from the command line.
 %patch0 -p1 -b .copy
 %patch2 -p1
 %patch3 -p2
+%patch4 -p1
 
 %build
 %configure --without-included-regex
@@ -73,6 +76,16 @@ fi
 %{_mandir}/man*/*
 
 %changelog
+* Fri Jan 23 2026  Jakub Martisko <jamartis@redhat.com> - 4.5-6
+- lib/dfa.c: Increase the maximum size of the transitions table
+- After changes introduced between sed 4.2 and 4.4, some regexps
+  started to hit the table size limits. This lead to repeated deletion
+  and rebuilding of the table, leading to massive performance drops.
+  While the core issue is still present, this change should at least
+  help by moving the threshold of the regexp complexity that triggers the 
+  table rebuilds.
+- Resolves: RHEL-17133
+
 * Tue Oct 05 2021  Jakub Martisko <jamartis@redhat.com> - 4.5-5
 - Minor cleanup - remove unused patch from the spec file too (related to 4.5-3)
 - Resolves: rhbz#1869253