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Code Activity

MDEV-23844 Atomic DROP TABLE (single table)

Browse Source 
Logging logic:
- Log tables, just before they are dropped, to the ddl log
- After the last table for the statement is dropped, log an xid for the
  whole ddl log event

In case of crash:
- Remove first any active DROP TABLE events from the ddl log that matches
  xids found in binary log (this mean the drop was successful and was
  propery logged).
- Loop over all active DROP TABLE events
  - Ensure that the table is completely dropped
- Write a DROP TABLE entry to the binary log with the dropped tables.

Other things:
- Added code to ha_drop_table() to be able to tell the difference if
  a get_new_handler() failed because of out-of-memory or because the
  handler refused/was not able to create a a handler. This was needed
  to get sequences to work as sequences needs a share object to be passed
  to get_new_handler()
- TC_LOG_BINLOG::recover() was changed to always collect Xid's from the
  binary log and always call ddl_log_close_binlogged_events(). This was
  needed to be able to collect DROP TABLE events with embedded Xid's
  (used by ddl log).
- Added a new variable "$grep_script" to binlog filter to be able to find
  only rows that matches a regexp.
- Had to adjust some test that changed because drop statements are a bit
  larger in the binary log than before (as we have to store the xid)

Other things:
- MDEV-25588 Atomic DDL: Binlog query event written upon recovery is corrupt
  fixed (in the original commit).
This commit is contained in:
Monty
2020-12-04 18:23:40 +02:00
committed by Sergei Golubchik
parent 47010ccffa
commit e3cfb7c803
15 changed files with 1136 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
sql/sql_table.cc
View File

@ -56,6 +56,7 @@
#include "tztime.h"
#include "sql_insert.h" // binlog_drop_table
#include "ddl_log.h"
#include "debug_sync.h" // debug_crash_here()
#include <algorithm>
#ifdef __WIN__
@ -1139,9 +1140,11 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
char path[FN_REFLEN + 1];
LEX_CSTRING alias= null_clex_str;
StringBuffer<160> unknown_tables(system_charset_info);
uint not_found_errors= 0;
DDL_LOG_STATE ddl_log_state;
const char *comment_start;
uint not_found_errors= 0, table_count= 0, non_temp_tables_count= 0;
int error= 0;
int non_temp_tables_count= 0;
uint32 comment_len;
bool trans_tmp_table_deleted= 0, non_trans_tmp_table_deleted= 0;
bool non_tmp_table_deleted= 0;
bool is_drop_tmp_if_exists_added= 0;
@ -1154,6 +1157,8 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
DBUG_ENTER("mysql_rm_table_no_locks");
unknown_tables.length(0);
comment_len= get_comment(thd, if_exists ? 17:9, &comment_start);
/*
Prepares the drop statements that will be written into the binary
log as follows:
@ -1204,6 +1209,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
built_non_trans_tmp_query.set_charset(system_charset_info);
built_non_trans_tmp_query.copy(built_trans_tmp_query);
}
bzero(&ddl_log_state, sizeof(ddl_log_state));
for (table= tables; table; table= table->next_local)
{
@ -1213,6 +1219,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
bool table_dropped= 0;
const LEX_CSTRING db= table->db;
const LEX_CSTRING table_name= table->table_name;
LEX_CSTRING cpath= {0,0};
handlerton *hton= 0;
Table_type table_type;
size_t path_length= 0;
@ -1347,6 +1354,8 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
continue;
}
lex_string_set3(&cpath, path, (size_t) (path_end - path));
{
char engine_buf[NAME_CHAR_LEN + 1];
LEX_CSTRING engine= { engine_buf, 0 };
@ -1363,6 +1372,17 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
thd->replication_flags= 0;
was_view= table_type == TABLE_TYPE_VIEW;
if (!table_count++)
{
LEX_CSTRING comment= {comment_start, (size_t) comment_len};
if (ddl_log_drop_table_init(thd, &ddl_log_state, &comment))
{
error= 1;
goto err;
}
}
if ((table_type == TABLE_TYPE_UNKNOWN) || (was_view && !drop_view) ||
(table_type != TABLE_TYPE_SEQUENCE && drop_sequence))
{
@ -1376,6 +1396,8 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
was_table|= wrong_drop_sequence;
error= table_type == TABLE_TYPE_UNKNOWN ? ENOENT : -1;
tdc_remove_table(thd, db.str, table_name.str);
if (wrong_drop_sequence)
goto report_error;
}
else
{
@ -1411,7 +1433,17 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
log_if_exists= 1;
bool enoent_warning= !dont_log_query && !(hton && hton->discover_table);
error= ha_delete_table(thd, hton, path, &db, &table_name, enoent_warning);
if (ddl_log_drop_table(thd, &ddl_log_state, hton, &cpath, &db,
&table_name))
{
error= -1;
goto err;
}
debug_crash_here("ddl_log_drop_before_delete_table");
error= ha_delete_table(thd, hton, path, &db, &table_name,
enoent_warning);
debug_crash_here("ddl_log_drop_after_delete_table");
if (!error)
table_dropped= 1;
@ -1473,11 +1505,18 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
scan all engines try to drop the table from there.
This is to ensure we don't have any partial table files left.
*/
if (non_existing_table_error(error) && !wrong_drop_sequence)
if (non_existing_table_error(error))
{
int ferror= 0;
DBUG_ASSERT(!was_view);
if (ddl_log_drop_table(thd, &ddl_log_state, hton, &cpath, &db,
&table_name))
{
error= -1;
goto err;
}
/* Remove extension for delete */
*path_end= '\0';
ferror= ha_delete_table_force(thd, path, &db, &table_name);
@ -1509,13 +1548,19 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
if (thd->replication_flags & OPTION_IF_EXISTS)
log_if_exists= 1;
debug_crash_here("ddl_log_drop_before_drop_trigger");
ddl_log_update_phase(&ddl_log_state, DDL_DROP_PHASE_TRIGGER);
debug_crash_here("ddl_log_drop_before_drop_trigger2");
if (likely(!error) || non_existing_table_error(error))
{
if (Table_triggers_list::drop_all_triggers(thd, &db, &table_name,
MYF(MY_WME | MY_IGNORE_ENOENT)))
error= error ? error : -1;
}
debug_crash_here("ddl_log_drop_after_drop_trigger");
report_error:
if (error)
{
StringBuffer<FN_REFLEN> tbl_name(system_charset_info);
@ -1565,6 +1610,7 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
table_name.str, (uint)table_name.length);
mysql_audit_drop_table(thd, table);
}
ddl_log_update_phase(&ddl_log_state, DDL_DROP_PHASE_BINLOG);
if (!dont_log_query &&
(!error || table_dropped || non_existing_table_error(error)))
@ -1621,6 +1667,7 @@ err:
query_cache_invalidate3(thd, tables, 0);
if (!dont_log_query && mysql_bin_log.is_open())
{
debug_crash_here("ddl_log_drop_before_binlog");
if (non_trans_tmp_table_deleted)
{
/* Chop of the last comma */
@ -1648,8 +1695,6 @@ err:
if (non_tmp_table_deleted)
{
String built_query;
const char *comment_start;
uint32 comment_len;
built_query.set_charset(thd->charset());
built_query.append(STRING_WITH_LEN("DROP "));
@ -1659,8 +1704,7 @@ err:
built_query.append(STRING_WITH_LEN("IF EXISTS "));
/* Preserve comment in original query */
if ((comment_len= get_comment(thd, if_exists ? 17:9,
&comment_start)))
if (comment_len)
{
built_query.append(comment_start, comment_len);
built_query.append(' ');
@ -1670,13 +1714,18 @@ err:
normal_tables.chop();
built_query.append(normal_tables.ptr(), normal_tables.length());
built_query.append(generated_by_server);
thd->binlog_xid= thd->query_id;
ddl_log_update_xid(&ddl_log_state, thd->binlog_xid);
error |= (thd->binlog_query(THD::STMT_QUERY_TYPE,
built_query.ptr(),
built_query.length(),
TRUE, FALSE, FALSE, 0) > 0);
thd->binlog_xid= 0;
}
debug_crash_here("ddl_log_drop_after_binlog");
}
}
ddl_log_complete(&ddl_log_state);
if (!drop_temporary)
{