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MDEV-39430: Store non-default system variables #5019

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MDEV-39430: Store non-default system variables #5019

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110 changes: 90 additions & 20 deletions sql/opt_context_store_replay.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ using namespace json_reader;
as "REPLACE INTO table_name VALUES(...);" statements.
The table_name would either be the table referred in the query or
one of MYSQL.TABLE_STATS, MYSQL.COLUMN_STATS, MYSQL.INDEX_STATS.
functions store_system_variables(), and dump_eits_stats() are used
functions store_variables(), and dump_eits_stats() are used
for achieving this purpose. All these statements are also recorded in
the "optimizer_context" Information Schema table.
*/
Expand Down Expand Up @@ -405,6 +405,36 @@ static bool is_optimizer_related_var(const char **sys_vars,
return false;
}

static void store_variable(THD *thd, String &sql_script, bool is_global,
const char *var_name, const char *value, size_t len,
bool req_quote)
{
sql_script.append(STRING_WITH_LEN("SET "));

if (is_global)
sql_script.append(STRING_WITH_LEN("GLOBAL "));
else
sql_script.append(STRING_WITH_LEN("@"));

sql_script.append(var_name, strlen(var_name));
sql_script.append(STRING_WITH_LEN("="));

if (value)
{
if (req_quote)
sql_script.append(STRING_WITH_LEN("'"));

sql_script.append(value, len);

if (req_quote)
sql_script.append(STRING_WITH_LEN("'"));
}
else
sql_script.append(STRING_WITH_LEN("NULL"));

sql_script.append(STRING_WITH_LEN(";\n\n"));
}

/*
@brief
Save current values of optimizer variables: append to sql_script
Expand All @@ -416,34 +446,41 @@ static void store_system_variables(THD *thd, String &sql_script)
// hold the lock until the end of this method.
// follows the same pattern as in sql_show.cc#fill_variables()
mysql_prlock_rdlock(&LOCK_system_variables_hash);

if (!thd->variables.dynamic_variables_ptr ||
global_system_variables.dynamic_variables_head >
thd->variables.dynamic_variables_head)
sync_dynamic_session_variables(thd, true);

SHOW_VAR *all_session_vars= enumerate_sys_vars(thd, true, SHOW_OPT_SESSION);
size_t len;
StringBuffer<1024> buf;
const char *pos;

for (SHOW_VAR *show_var= all_session_vars; show_var->name != NULL;
show_var++)
{
if (is_optimizer_related_var(excluded_sys_vars, show_var->name))
sys_var *var= (sys_var *) show_var->value;
bool is_global_var= var->check_type(SHOW_OPT_SESSION);
bool req_quote;

// don't store the variables related to
// 1. context
// 2. thread
// 3. read_only
if (is_optimizer_related_var(excluded_sys_vars, show_var->name) ||
var->is_readonly() || strstr(show_var->name, "thread") != NULL)
continue;

if (strstr(show_var->name, "optimizer") != NULL ||
is_optimizer_related_var(opt_related_sys_vars, show_var->name))
is_optimizer_related_var(opt_related_sys_vars, show_var->name) ||
(var->value_origin != sys_var::COMPILE_TIME)) // has non-default value
{
sys_var *var= (sys_var *) show_var->value;
mysql_mutex_lock(&LOCK_global_system_variables);
pos= get_one_variable(thd, show_var, SHOW_OPT_SESSION, show_var->type,
NULL, &charset_info, buf.c_ptr_safe(), &len);
mysql_mutex_unlock(&LOCK_global_system_variables);
sql_script.append(STRING_WITH_LEN("SET "));

if (var->check_type(SHOW_OPT_SESSION))
sql_script.append(STRING_WITH_LEN("GLOBAL "));

sql_script.append(show_var->name, strlen(show_var->name));
sql_script.append(STRING_WITH_LEN("="));
switch (var->show_type())
{
case SHOW_DOUBLE:
Expand All @@ -455,25 +492,58 @@ static void store_system_variables(THD *thd, String &sql_script)
case SHOW_SLONG:
case SHOW_SLONGLONG:
case SHOW_SIZE_T:
sql_script.append(pos, len);
req_quote= false;
break;
default:
sql_script.append(STRING_WITH_LEN("'"));
sql_script.append(pos, len);
sql_script.append(STRING_WITH_LEN("'"));
req_quote= true;
break;
}
sql_script.append(STRING_WITH_LEN(";\n\n"));
store_variable(thd, sql_script, is_global_var, show_var->name, pos, len,
req_quote);
}
}
mysql_prlock_unlock(&LOCK_system_variables_hash);
}

// static void store_user_variables(THD *thd, String &sql_script)
// {
// HASH *user_vars_hash= &thd->user_vars;

// // A buffer to hold the string representation of the variable's value.
// char val_buffer[MAX_FIELD_WIDTH];
// String str_val(val_buffer, sizeof(val_buffer), system_charset_info);
// char *replay_ctx_var= thd->variables.optimizer_replay_context;

// for (uint i= 0; i < user_vars_hash->records; i++)
// {
// user_var_entry *entry=
// (user_var_entry *) my_hash_element(user_vars_hash, i);

// if (entry && strcmp(entry->name.str, replay_ctx_var) != 0)
// {
// bool is_null;
// String *value_str= entry->val_str(&is_null, &str_val, 0);
// if (is_null)
// store_variable(thd, sql_script, false, entry->name.str, NULL, 0,
// true);
// else
// store_variable(thd, sql_script, false, entry->name.str,
// value_str->c_ptr_safe(), value_str->length(), true);
// }
// }
// }

static void store_variables(THD *thd, String &sql_script)
{
// store_user_variables(thd, sql_script);
store_system_variables(thd, sql_script);
}

/*
@brief
Append the "create database db_name" DDL statement to sql_script, if it is
not already present in the db_name_hash.
Also, append "use database db_name" if the flag req_use_db_stmt is set.
Append the "create database db_name" DDL statement to sql_script, if it
is not already present in the db_name_hash. Also, append "use database
db_name" if the flag req_use_db_stmt is set.

@return
0 OK
Expand Down Expand Up @@ -552,8 +622,8 @@ bool store_optimizer_context(THD *thd)
Json_writer ctx_writer;
Json_writer_object context(&ctx_writer);
Json_writer_array context_list(&ctx_writer, "list_contexts");
sql_script.append(STRING_WITH_LEN("SET NAMES utf8mb4;\n\n "));
store_system_variables(thd, sql_script);
sql_script.append(STRING_WITH_LEN("SET NAMES utf8mb4;\n\n"));
store_variables(thd, sql_script);
HASH table_name_hash;
HASH db_name_hash;
List<TABLE_LIST> tables_list;
Expand Down
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