diff --git a/extra/mariadb/0007-MDEV-20646.patch b/extra/mariadb/0007-MDEV-20646.patch
new file mode 100644
index 000000000..53ca497e9
--- /dev/null
+++ b/extra/mariadb/0007-MDEV-20646.patch
@@ -0,0 +1,45 @@
+commit d4edb0510ec1189f65850bb47977e94ed98b1f71
+Author: Sergei Petrunia <psergey@askmonty.org>
+Date:   Wed Nov 13 18:53:59 2019 +0300
+
+    MDEV-20646: 10.3.18 is slower than 10.3.17
+    
+    Fix incorrect change introduced in the fix for MDEV-20109.
+    
+    The patch tried to compute a more precise estimate for the record_count
+    value in SJ-Materialization-Scan strategy (in
+    Sj_materialization_picker::check_qep).  However the new formula is worse
+    as it produces extremely optimistic results in common cases where
+    SJ-Materialization-Scan should be used)
+    
+    The old formula produces pessimistic results in cases when Sj-Materialization-
+    Scan is unlikely to be a good choice anyway. So, the old behavior is better.
+
+diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
+index aeafc13998a..a8afd952a4d 100644
+--- a/sql/opt_subselect.cc
++++ b/sql/opt_subselect.cc
+@@ -3029,7 +3029,22 @@ bool Sj_materialization_picker::check_qep(JOIN *join,
+ 
+     *strategy= SJ_OPT_MATERIALIZE_SCAN;
+     *read_time=    prefix_cost;
+-    *record_count= prefix_rec_count / mat_info->rows_with_duplicates;
++    /*
++      Note: the next line means we did not remove the subquery's fanout from
++      *record_count. It needs to be removed, as the join prefix is
++
++        ntX  SJM-SCAN(it1 ... itN) | (ot1 ... otN) ...
++
++      here, the SJM-SCAN may have introduced subquery's fanout (duplicate rows,
++      rows that don't have matches in ot1_i). All this fanout is gone after
++      table otN (or earlier) but taking it into account is hard.
++
++      Some consolation here is that SJM-Scan strategy is applicable when the
++      subquery is smaller than tables otX. If the subquery has large cardinality,
++      we can greatly overestimate *record_count here, but it doesn't matter as
++      SJ-Materialization-Lookup is a better strategy anyway.
++    */
++    *record_count= prefix_rec_count;
+     *handled_fanout= mat_nest->sj_inner_tables;
+     return TRUE;
+   }
diff --git a/extra/mariadb/PKGBUILD b/extra/mariadb/PKGBUILD
index b3383ff06..b7bff56a3 100644
--- a/extra/mariadb/PKGBUILD
+++ b/extra/mariadb/PKGBUILD
@@ -9,23 +9,29 @@ pkgbase=mariadb
 pkgname=('mariadb-libs' 'mariadb-clients' 'mariadb' 'mytop')
 pkgdesc='Fast SQL database server, derived from MySQL'
 pkgver=10.4.10
-pkgrel=1
+pkgrel=2
 arch=('x86_64')
 license=('GPL')
 url='https://mariadb.org/'
 makedepends=('boost' 'bzip2' 'cmake' 'jemalloc' 'libaio' 'libxml2' 'lz4' 'lzo'
              'openssl' 'systemd' 'zlib' 'zstd')
 validpgpkeys=('199369E5404BD5FC7D2FE43BCBCB082A1BB943DB') # MariaDB Package Signing Key <package-signing-key@mariadb.org>
-source=("https://downloads.mariadb.org/interstitial/mariadb-${pkgver}/source/mariadb-${pkgver}.tar.gz"{,.asc}
+# The default links with mirror redirection fail for signatures, specific
+# mirrors may be out of date every now and then. Let's use the upstream
+# rsync source and hope it does not hurt them too much.
+# https://mariadb.com/kb/en/library/mirror-sites-for-mariadb/
+source=("rsync://rsync.osuosl.org/mariadb/mariadb-${pkgver}/source/mariadb-${pkgver}.tar.gz"{,.asc}
         '0001-arch-specific.patch'
         '0002-systemd-sysusers-tmpfiles.patch'
         '0005-fix-galera_recovery-with-fs.protected_regular-enabled.patch'
+        '0007-MDEV-20646.patch'
         '0001-libatomic.patch')
 sha256sums=('cd50fddf86c2a47405737e342f78ebd40d5716f0fb32b976245de713bed01421'
             'SKIP'
             'ce72ea1563ad773e00e8b1c299babea176abae1102827c2f743921e9de615041'
             '3e83467af80fbd53400a201a34fc858b88509ea8e88b10709947eb66545f9457'
             'c8c801f80924ccb97b499552fe1c532b3ebf8f86cdfc0d23715d4adb1a8810f0'
+            '825d4ab1601c9e97bf24857bcfd8bed2b6d8ad15a4c2411c7867bff2333b09d8'
             '1c7360453b6e964c6546cbbb10fff697f6227554eba716b2a1df74f7c2613d95')
 
 prepare() {
@@ -47,6 +53,9 @@ prepare() {
   # https://github.com/MariaDB/server/pull/1137
   patch -Np1 < ../0005-fix-galera_recovery-with-fs.protected_regular-enabled.patch
 
+  # MDEV-20646: 10.3.18 is slower than 10.3.17
+  patch -Np1 < ../0007-MDEV-20646.patch
+
   if [[ $CARCH == arm || $CARCH == armv6h ]]; then
     patch -p1 -i ../0001-libatomic.patch
   fi