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Fixed bug#11753738 (formely known as bug#45235) - 5.1 DOES NOT SUPPORT 5.0-ONLY

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SYNTAX TRIGGERS IN ANY WAY

Table with triggers which were using deprecated (5.0-only) syntax became
unavailable for any DML and DDL after upgrade to 5.1 version of server.
Attempt to execute any statement on such a table resulted in parsing
error reported. Since this included DROP TRIGGER and DROP TABLE
statements (actually, the latter was allowed but was not functioning
properly for such tables) it was impossible to fix the problem without
manual operations on .TRG and .TRN files in data directory.

The problem was that failure to parse trigger body (due to 5.0-only
syntax) when opening trigger file for a table prevented the table
from being open. This made all operations on the table impossible
(except DROP TABLE which due to peculiarity in its implementation
dropped the table but left trigger files around).

This patch solves this problem by silencing error which occurs when
we parse trigger body during table open. Error message is preserved
for the future use and table is marked as having a broken trigger.
We also try to analyze parse tree to recover trigger name, which
will be needed in order to drop the broken trigger. DML statements
which invoke triggers on the table marked as having broken trigger
are prohibited and emit saved error message. The same happens for
DDL which change triggers except DROP TRIGGER and DROP TABLE which
try their best to do what was requested. Table becomes no longer
marked as having broken trigger when last such trigger is dropped.

mysql-test/r/trigger-compat.result:
  Add results for test case for bug#45235
mysql-test/t/trigger-compat.test:
  Add test case for bug#45235.
sql/sp_head.cc:
  Added protection against MEM_ROOT double restoring to
  sp_head::restore_thd_mem_root() method. Since this
  method can be sometimes called twice during parsing
  of stored routine (the first time during normal flow
  of parsing, and the second time when a syntax error
  is detected) we need to shortcut execution of the
  method to avoid damaging MEM_ROOT by the second
  consecutive call to this method.
sql/sql_trigger.cc:
  Added error handler Deprecated_trigger_syntax_handler to 
  catch non-OOM errors during parsing of trigger body.
  
  Added handling of parse errors into method 
  Table_triggers_list::check_n_load().
sql/sql_trigger.h:
  Added new members to handle broken triggers and error messages.
This commit is contained in:
Dmitry Shulga
2011-06-10 10:52:39 +07:00
parent 4412b5dab6
commit 1fea8c1b90
7 changed files with 464 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

148
sql/sql_trigger.cc
View File

@ -19,6 +19,7 @@
#include "sp_head.h"
#include "sql_trigger.h"
#include "parse_file.h"
#include <mysys_err.h>
/*************************************************************************/
@ -292,6 +293,52 @@ private:
};
/**
An error handler that catches all non-OOM errors which can occur during
parsing of trigger body. Such errors are ignored and corresponding error
message is used to construct a more verbose error message which contains
name of problematic trigger. This error message is later emitted when
one tries to perform DML or some of DDL on this table.
Also, if possible, grabs name of the trigger being parsed so it can be
used to correctly drop problematic trigger.
*/
class Deprecated_trigger_syntax_handler : public Internal_error_handler
{
private:
char m_message[MYSQL_ERRMSG_SIZE];
LEX_STRING *m_trigger_name;
public:
Deprecated_trigger_syntax_handler() : m_trigger_name(NULL) {}
virtual bool handle_error(uint sql_errno, const char *message,
MYSQL_ERROR::enum_warning_level level, THD *thd)
{
if (sql_errno != EE_OUTOFMEMORY &&
sql_errno != ER_OUT_OF_RESOURCES)
{
if(thd->lex->spname)
m_trigger_name= &thd->lex->spname->m_name;
if (m_trigger_name)
my_snprintf(m_message, sizeof(m_message),
"Trigger '%s' has an error in its body: '%s'",
m_trigger_name->str, message);
else
my_snprintf(m_message, sizeof(m_message),
"Unknown trigger has an error in its body: '%s'",
message);
return true;
}
return false;
}
LEX_STRING *get_trigger_name() { return m_trigger_name; }
char *get_error_message() { return m_message; }
};
/**
Create or drop trigger for table.
@ -575,6 +622,8 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables,
LEX_STRING *trg_connection_cl_name;
LEX_STRING *trg_db_cl_name;
if (check_for_broken_triggers())
return true;
/* Trigger must be in the same schema as target table. */
if (my_strcasecmp(table_alias_charset, table->s->db.str,
@ -848,7 +897,7 @@ static bool rm_trigger_file(char *path, const char *db,
@param path char buffer of size FN_REFLEN to be used
for constructing path to .TRN file.
@param db trigger's database name
@param table_name trigger's name
@param trigger_name trigger's name
@retval
False success
@ -1312,12 +1361,11 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
lex_start(thd);
thd->spcont= NULL;
if (parse_sql(thd, & parser_state, creation_ctx))
{
/* Currently sphead is always deleted in case of a parse error */
DBUG_ASSERT(lex.sphead == 0);
goto err_with_lex_cleanup;
}
Deprecated_trigger_syntax_handler error_handler;
thd->push_internal_handler(&error_handler);
bool parse_error= parse_sql(thd, & parser_state, creation_ctx);
thd->pop_internal_handler();
/*
Not strictly necessary to invoke this method here, since we know
that we've parsed CREATE TRIGGER and not an
@ -1328,6 +1376,52 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
*/
lex.set_trg_event_type_for_tables();
if (parse_error)
{
if (!triggers->m_has_unparseable_trigger)
triggers->set_parse_error_message(error_handler.get_error_message());
/* Currently sphead is always set to NULL in case of a parse error */
DBUG_ASSERT(lex.sphead == 0);
if (error_handler.get_trigger_name())
{
LEX_STRING *trigger_name;
const LEX_STRING *orig_trigger_name= error_handler.get_trigger_name();
if (!(trigger_name= alloc_lex_string(&table->mem_root)) ||
!(trigger_name->str= strmake_root(&table->mem_root,
orig_trigger_name->str,
orig_trigger_name->length)))
goto err_with_lex_cleanup;
trigger_name->length= orig_trigger_name->length;
if (triggers->names_list.push_back(trigger_name,
&table->mem_root))
goto err_with_lex_cleanup;
}
else
{
/*
The Table_triggers_list is not constructed as a list of
trigger objects as one would expect, but rather of lists of
properties of equal length. Thus, even if we don't get the
trigger name, we still fill all in all the lists with
placeholders as we might otherwise create a skew in the
lists. Obviously, this has to be refactored.
*/
LEX_STRING *empty= alloc_lex_string(&table->mem_root);
if (!empty)
goto err_with_lex_cleanup;
empty->str= const_cast<char*>("");
empty->length= 0;
if (triggers->names_list.push_back(empty, &table->mem_root))
goto err_with_lex_cleanup;
}
lex_end(&lex);
continue;
}
lex.sphead->set_info(0, 0, &lex.sp_chistics, (ulong) *trg_sql_mode);
int event= lex.trg_chistics.event;
@ -1368,8 +1462,8 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
if (triggers->names_list.push_back(&lex.sphead->m_name,
&table->mem_root))
goto err_with_lex_cleanup;
goto err_with_lex_cleanup;
if (!(on_table_name= alloc_lex_string(&table->mem_root)))
goto err_with_lex_cleanup;
@ -1394,9 +1488,8 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
char fname[NAME_LEN + 1];
DBUG_ASSERT((!my_strcasecmp(table_alias_charset, lex.query_tables->db, db) ||
(check_n_cut_mysql50_prefix(db, fname, sizeof(fname)) &&
!my_strcasecmp(table_alias_charset, lex.query_tables->db, fname))) &&
(!my_strcasecmp(table_alias_charset, lex.query_tables->table_name,
table_name) ||
!my_strcasecmp(table_alias_charset, lex.query_tables->db, fname))));
DBUG_ASSERT((!my_strcasecmp(table_alias_charset, lex.query_tables->table_name, table_name) ||
(check_n_cut_mysql50_prefix(table_name, fname, sizeof(fname)) &&
!my_strcasecmp(table_alias_charset, lex.query_tables->table_name, fname))));
#endif
@ -1680,6 +1773,13 @@ bool Table_triggers_list::drop_all_triggers(THD *thd, char *db, char *name)
while ((trigger= it_name++))
{
/*
Trigger, which body we failed to parse during call
Table_triggers_list::check_n_load(), might be missing name.
Such triggers have zero-length name and are skipped here.
*/
if (trigger->length == 0)
continue;
if (rm_trigname_file(path, db, trigger->str))
{
/*
@ -1903,6 +2003,11 @@ bool Table_triggers_list::change_table_name(THD *thd, const char *db,
}
if (table.triggers)
{
if (table.triggers->check_for_broken_triggers())
{
result= 1;
goto end;
}
LEX_STRING old_table_name= { (char *) old_table, strlen(old_table) };
LEX_STRING new_table_name= { (char *) new_table, strlen(new_table) };
/*
@ -1991,6 +2096,9 @@ bool Table_triggers_list::process_triggers(THD *thd,
sp_head *sp_trigger= bodies[event][time_type];
SELECT_LEX *save_current_select;
if (check_for_broken_triggers())
return true;
if (sp_trigger == NULL)
return FALSE;
@ -2069,6 +2177,22 @@ void Table_triggers_list::mark_fields_used(trg_event_type event)
}
/**
Signals to the Table_triggers_list that a parse error has occured when
reading a trigger from file. This makes the Table_triggers_list enter an
error state flagged by m_has_unparseable_trigger == true. The error message
will be used whenever a statement invoking or manipulating triggers is
issued against the Table_triggers_list's table.
@param error_message The error message thrown by the parser.
*/
void Table_triggers_list::set_parse_error_message(char *error_message)
{
m_has_unparseable_trigger= true;
strcpy(m_parse_error_message, error_message);
}
/**
Trigger BUG#14090 compatibility hook.