Added s3_debug to be able to debug s3 connections

libmysqld/libmysql.c

@@ -5030,5 +5030,9 @@ uint8_t ms3_move(ms3_st *ms3, const char *source_bucket, const char *source_key,
   return 1;
 }
 
+void ms3_debug()
+{
+}
+
 C_MODE_END
 #endif /* WITH_S3_STORAGE_ENGINE */

mysql-test/suite/s3/basic.result

@@ -88,6 +88,7 @@ Variable_name	Value
 s3_access_key	X
 s3_block_size	X
 s3_bucket	X
+s3_debug	X
 s3_host_name	X
 s3_pagecache_age_threshold	X
 s3_pagecache_buffer_size	X

storage/maria/ha_s3.cc

@@ -78,6 +78,7 @@ static ulonglong s3_pagecache_buffer_size;
 static char *s3_bucket, *s3_access_key=0, *s3_secret_key=0, *s3_region;
 static char *s3_host_name;
 static char *s3_tmp_access_key=0, *s3_tmp_secret_key=0;
+static my_bool s3_debug= 0;
 handlerton *s3_hton= 0;
 
 /* Don't show access or secret keys to users if they exists */
@@ -117,6 +118,11 @@ static MYSQL_SYSVAR_ULONG(block_size, s3_block_size,
        "Block size for S3", 0, 0,
        4*1024*1024, 65536, 16*1024*1024, 8192);
 
+static MYSQL_SYSVAR_BOOL(debug, s3_debug,
+       PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
+      "Generates trace file from libmarias3 on stderr for debugging",
+       0, 0, 0);
+
 static MYSQL_SYSVAR_ENUM(protocol_version, s3_protocol_version,
                          PLUGIN_VAR_RQCMDARG,
                          "Protocol used to communication with S3. One of "
@@ -173,7 +179,6 @@ static MYSQL_SYSVAR_STR(region, s3_region,
       "AWS region",
        0, 0, "");
 
-
 ha_create_table_option s3_table_option_list[]=
 {
   /*
@@ -696,6 +701,8 @@ static int ha_s3_init(void *p)
   s3_pagecache.big_block_read= s3_block_read;
   s3_pagecache.big_block_free= s3_free;
   s3_init_library();
+  if (s3_debug)
+    ms3_debug();
   return res ? HA_ERR_INITIALIZATION : 0;
 }
 
@@ -716,6 +723,7 @@ static SHOW_VAR status_variables[]= {
 
 static struct st_mysql_sys_var* system_variables[]= {
   MYSQL_SYSVAR(block_size),
+  MYSQL_SYSVAR(debug),
   MYSQL_SYSVAR(protocol_version),
   MYSQL_SYSVAR(pagecache_age_threshold),
   MYSQL_SYSVAR(pagecache_buffer_size),