BUG#16217 forced to introduce a separate mysql client command to adopt its

internal charset to one associated with currently being handled query. 
To note such a query can come from interactive client either.

There was a discussion within replication team and Monty who's suggestion won.
It avoids straightforward parsing of all `set' queries that could affect client side 
character set. 
According to the idea, mysql client does not parse `set' queries but rather cares of
`charset new_cs_name' command.
This command is generated by mysqlbinlog in form of exclaiming comment (Lars' suggestion)
so that enlightened clients like `mysql' knows what to do with it.

Interactive human can switch between many multi-byte charsets during the session 
providing the command explicitly. 
To note that setting new internal mysql's charset does not
trigger sending any `SET' sql statement to the server. 


client/mysql.cc:
  BUG#16217 revealed the problem of switching between charsets in mysql client.
  Such switching is necessary in a case when being scanned query consists of 
  multi-byte chars and internal charset was initialized differently. mysql finds 
  `/' escape and misiterprete it 
  while in fact one could be a part of a multi-byte symbol like the bug page reported. 
  
  This patch extends mysql `charset' command, '\C' shortcut.
mysql-test/r/ctype_ucs_binlog.result:
  comment line generated by mysqlbinlog for processing of logs with multi-byte chars.
mysql-test/r/mysql.result:
  results are altered due to #16217
mysql-test/r/mysqlbinlog.result:
  Results are altered due to #16217
mysql-test/r/mysqlbinlog2.result:
  commeted command for mysql client due to multi-byte binlog
mysql-test/r/rpl_charset.result:
  commented command for mysql due to multi-byte binlogs
mysql-test/r/rpl_timezone.result:
  commented command for mysql client due to multi-byte binlogs
mysql-test/r/user_var-binlog.result:
  commented command for mysql client due to multi-byte binlogs
mysql-test/t/mysql.test:
  Main test for mysql client is extended to check `charset' command.
mysql-test/t/mysqlbinlog.test:
  Checking how /*! \C cs_name */ are added to the output of mysqlbinlog.
  The exclaiming comment is for further processing by mysql client.
  The added part mimics the failure to recover tables from binlog - see BUG#16217.
sql/log_event.cc:
  Sending into output instructions for mysql client to switch internally 
  to appropriate charset.
  mysql client is supposed to be invoked with --default-character-set=
  "to default character set of the server created the binlog".

1 files changed, 25 insertions, 1 deletions

diff --git a/client/mysql.cc b/client/mysql.cc
index 98af6561966..8d578aac58b 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -194,7 +194,7 @@ static int com_quit(String *str,char*),
 	   com_connect(String *str,char*), com_status(String *str,char*),
 	   com_use(String *str,char*), com_source(String *str, char*),
 	   com_rehash(String *str, char*), com_tee(String *str, char*),
-           com_notee(String *str, char*),
+           com_notee(String *str, char*), com_charset(String *str,char*),
            com_prompt(String *str, char*), com_delimiter(String *str, char*),
      com_warnings(String *str, char*), com_nowarnings(String *str, char*);
 
@@ -268,6 +268,8 @@ static COMMANDS commands[] = {
     "Set outfile [to_outfile]. Append everything into given outfile." },
   { "use",    'u', com_use,    1,
     "Use another database. Takes database name as argument." },
+  { "charset",    'C', com_charset,    1,
+    "Switch to another charset. Might be needed for processing binlog with multi-byte charsets." },
   { "warnings", 'W', com_warnings,  0,
     "Show warnings after every statement." },
   { "nowarning", 'w', com_nowarnings, 0,
@@ -1909,6 +1911,28 @@ com_clear(String *buffer,char *line __attribute__((unused)))
   return 0;
 }
 
+	/* ARGSUSED */
+static int
+com_charset(String *buffer __attribute__((unused)), char *line)
+{
+  char buff[256], *param;
+  CHARSET_INFO * new_cs;
+  strmake(buff, line, sizeof(buff) - 1);
+  param= get_arg(buff, 0);
+  if (!param || !*param)
+  {
+    return put_info("Usage: \\C char_setname | charset charset_name", 
+		    INFO_ERROR, 0);
+  }
+  new_cs= get_charset_by_csname(param, MY_CS_PRIMARY, MYF(MY_WME));
+  if (new_cs)
+  {
+    charset_info= new_cs;
+    put_info("Charset changed", INFO_INFO);
+  }
+  else put_info("Charset is not found", INFO_INFO);
+  return 0;
+}
 
 /*
   Execute command