MDEV-21168: Active XA transactions stop slave from working after backup

was restored.

Optionally rollback prepared XA's on "mariabackup --prepare".

The fix MUST NOT be ported on 10.5+, as MDEV-742 fix solves the issue for
slaves.

1 files changed, 20 insertions, 14 deletions

diff --git a/sql/handler.cc b/sql/handler.cc
index 914a4dc07b1..d739ce7cd5b 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1806,29 +1806,33 @@ int ha_commit_or_rollback_by_xid(XID *xid, bool commit)
 
 
 #ifndef DBUG_OFF
-/**
-  @note
-    This does not need to be multi-byte safe or anything
-*/
-static char* xid_to_str(char *buf, XID *xid)
+/** Converts XID to string.
+
+@param[out] buf output buffer
+@param[in] xid XID to convert
+
+@return pointer to converted string
+
+@note This does not need to be multi-byte safe or anything */
+char *xid_to_str(char *buf, const XID &xid)
 {
   int i;
   char *s=buf;
   *s++='\'';
-  for (i=0; i < xid->gtrid_length+xid->bqual_length; i++)
+  for (i= 0; i < xid.gtrid_length + xid.bqual_length; i++)
   {
-    uchar c=(uchar)xid->data[i];
+    uchar c= (uchar) xid.data[i];
     /* is_next_dig is set if next character is a number */
     bool is_next_dig= FALSE;
     if (i < XIDDATASIZE)
     {
-      char ch= xid->data[i+1];
+      char ch= xid.data[i + 1];
       is_next_dig= (ch >= '0' && ch <='9');
     }
-    if (i == xid->gtrid_length)
+    if (i == xid.gtrid_length)
     {
       *s++='\'';
-      if (xid->bqual_length)
+      if (xid.bqual_length)
       {
         *s++='.';
         *s++='\'';
@@ -1949,7 +1953,8 @@ static my_bool xarecover_handlerton(THD *unused, plugin_ref plugin,
         {
 #ifndef DBUG_OFF
           char buf[XIDDATASIZE*4+6]; // see xid_to_str
-          DBUG_PRINT("info", ("ignore xid %s", xid_to_str(buf, info->list+i)));
+          DBUG_PRINT("info",
+                     ("ignore xid %s", xid_to_str(buf, info->list[i])));
 #endif
           xid_cache_insert(info->list+i, XA_PREPARED);
           info->found_foreign_xids++;
@@ -1979,7 +1984,8 @@ static my_bool xarecover_handlerton(THD *unused, plugin_ref plugin,
           if (rc == 0)
           {
             char buf[XIDDATASIZE*4+6]; // see xid_to_str
-            DBUG_PRINT("info", ("commit xid %s", xid_to_str(buf, info->list+i)));
+            DBUG_PRINT("info",
+                       ("commit xid %s", xid_to_str(buf, info->list[i])));
           }
 #endif
         }
@@ -1993,8 +1999,8 @@ static my_bool xarecover_handlerton(THD *unused, plugin_ref plugin,
           if (rc == 0)
           {
             char buf[XIDDATASIZE*4+6]; // see xid_to_str
-            DBUG_PRINT("info", ("rollback xid %s",
-                                xid_to_str(buf, info->list+i)));
+            DBUG_PRINT("info",
+                       ("rollback xid %s", xid_to_str(buf, info->list[i])));
           }
 #endif
         }