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cleanup: unpack_vcol_info_from_frm
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* do setup/cleanup for charset and arena only once per table
  not for every vcol
* don't copy every vcol expression into table's memroot for parsing,
  do it in a temporary String buffer that is freed at the end
* add asserts
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@vuvova
vuvova committed Dec 12, 2016
1 parent a72f1de commit 6b0f4c2
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Showing 2 changed files with 74 additions and 104 deletions.
10 changes: 8 additions & 2 deletions sql/sql_yacc.yy
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6221,15 +6221,21 @@ vcol_attribute:
;

parse_vcol_expr:
PARSE_VCOL_EXPR_SYM virtual_column_func
PARSE_VCOL_EXPR_SYM
{
/*
"PARSE_VCOL_EXPR" can only be used by the SQL server
when reading a '*.frm' file.
Prevent the end user from invoking this command.
*/
MYSQL_YYABORT_UNLESS(Lex->parse_vcol_expr);
Lex->last_field->vcol_info= $2;
}
expr
{
Virtual_column_info *v= add_virtual_expression(thd, $3);
if (!v)
MYSQL_YYABORT;
Lex->last_field->vcol_info= v;
}
;

Expand Down
168 changes: 66 additions & 102 deletions sql/table.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@
#define MYSQL57_GCOL_HEADER_SIZE 4

static Virtual_column_info * unpack_vcol_info_from_frm(THD *, MEM_ROOT *,
TABLE *, const uchar *, size_t, Virtual_column_info *, bool *);
TABLE *, String *, Virtual_column_info **, bool *);
static bool check_vcol_forward_refs(Field *, Virtual_column_info *);

/* INFORMATION_SCHEMA name */
Expand Down Expand Up @@ -971,8 +971,8 @@ static void mysql57_calculate_null_position(TABLE_SHARE *share,
expression
10.1-
byte 1 = 1 | 2
byte 2 = sql_type
byte 3 = stored_in_db
byte 2 = sql_type ; but TABLE::init_from_binary_frm_image()
byte 3 = stored_in_db ; has put expr_length here
[byte 4] = optional interval_id for sql_type (if byte 1 == 2)
expression
10.2+
Expand All @@ -986,20 +986,41 @@ static void mysql57_calculate_null_position(TABLE_SHARE *share,
bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
bool *error_reported)
{
CHARSET_INFO *save_character_set_client= thd->variables.character_set_client;
CHARSET_INFO *save_collation= thd->variables.collation_connection;
Query_arena *backup_stmt_arena_ptr= thd->stmt_arena;
const uchar *pos= table->s->vcol_defs.str;
const uchar *end= pos + table->s->vcol_defs.length;
Field **field_ptr= table->field - 1;
Field **vfield_ptr= table->vfield;
Field **dfield_ptr= table->default_field;
Virtual_column_info **check_constraint_ptr= table->check_constraints;
Query_arena backup_arena;
Virtual_column_info *vcol;
StringBuffer<MAX_FIELD_WIDTH> expr_str;
bool res= 1;
DBUG_ENTER("parse_vcol_defs");

if (check_constraint_ptr)
memcpy(table->check_constraints + table->s->field_check_constraints,
table->s->check_constraints,
table->s->table_check_constraints * sizeof(Virtual_column_info*));

DBUG_ASSERT(table->expr_arena == NULL);
/*
We need to use CONVENTIONAL_EXECUTION here to ensure that
any new items created by fix_fields() are not reverted.
*/
table->expr_arena= new (alloc_root(mem_root, sizeof(Query_arena)))
Query_arena(mem_root, Query_arena::STMT_CONVENTIONAL_EXECUTION);
if (!table->expr_arena)
DBUG_RETURN(1);

thd->set_n_backup_active_arena(table->expr_arena, &backup_arena);
thd->stmt_arena= table->expr_arena;
thd->update_charset(&my_charset_utf8mb4_general_ci, table->s->table_charset);
expr_str.append(&parse_vcol_keyword);

while (pos < end)
{
uint type, expr_length;
Expand All @@ -1024,7 +1045,7 @@ bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
if (!*field_ptr)
{
open_table_error(table->s, OPEN_FRM_CORRUPTED, 1);
DBUG_RETURN(1);
goto end;
}
type= (*field_ptr)->vcol_info->stored_in_db
? VCOL_GENERATED_STORED : VCOL_GENERATED_VIRTUAL;
Expand All @@ -1034,39 +1055,37 @@ bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
else
pos+= pos[0] == 2 ? 4 : 3; // MariaDB from 5.2 to 10.1
}

expr_str.length(parse_vcol_keyword.length);
expr_str.append((char*)pos, expr_length);

switch (type) {
case VCOL_GENERATED_VIRTUAL:
case VCOL_GENERATED_STORED:
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, pos, expr_length,
(*field_ptr)->vcol_info, error_reported);
DBUG_ASSERT((*field_ptr)->vcol_info->expr == NULL);
(*field_ptr)->vcol_info= vcol;
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
&((*field_ptr)->vcol_info), error_reported);
*(vfield_ptr++)= *field_ptr;
break;
case VCOL_DEFAULT:
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, pos, expr_length,
(*field_ptr)->default_value,
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
&((*field_ptr)->default_value),
error_reported);
DBUG_ASSERT((*field_ptr)->default_value->expr == NULL);
(*field_ptr)->default_value= vcol;
*(dfield_ptr++)= *field_ptr;
break;
case VCOL_CHECK_FIELD:
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, pos, expr_length,
(*field_ptr)->check_constraint,
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
&((*field_ptr)->check_constraint),
error_reported);
DBUG_ASSERT((*field_ptr)->check_constraint->expr == NULL);
(*field_ptr)->check_constraint= vcol;
*check_constraint_ptr++= vcol;
*check_constraint_ptr++= (*field_ptr)->check_constraint;
break;
case VCOL_CHECK_TABLE:
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, pos, expr_length,
*check_constraint_ptr, error_reported);
*check_constraint_ptr++= vcol;
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
check_constraint_ptr, error_reported);
check_constraint_ptr++;
break;
}
if (!vcol)
DBUG_RETURN(1);
goto end;
pos+= expr_length;
}

Expand All @@ -1076,16 +1095,16 @@ bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
Field *field= *field_ptr;
if (field->has_default_now_unireg_check())
{
char buf[256];
size_t len= my_snprintf(buf, sizeof(buf), "current_timestamp(%u)", field->decimals());
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, (uchar*)buf, len,
(*field_ptr)->default_value,
expr_str.length(parse_vcol_keyword.length);
expr_str.append(STRING_WITH_LEN("current_timestamp("));
expr_str.append_ulonglong(field->decimals());
expr_str.append(')');
vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
&((*field_ptr)->default_value),
error_reported);
DBUG_ASSERT((*field_ptr)->default_value->expr == NULL);
(*field_ptr)->default_value= vcol;
*(dfield_ptr++)= *field_ptr;
if (!field->default_value->expr)
DBUG_RETURN(1);
goto end;
}
else if (field->has_update_default_function() && !field->default_value)
*(dfield_ptr++)= *field_ptr;
Expand All @@ -1107,10 +1126,16 @@ bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
if (check_vcol_forward_refs(field, field->vcol_info) ||
check_vcol_forward_refs(field, field->check_constraint) ||
check_vcol_forward_refs(field, field->default_value))
DBUG_RETURN(1);
goto end;
}

DBUG_RETURN(0);
res=0;
end:
thd->restore_active_arena(table->expr_arena, &backup_arena);
thd->stmt_arena= backup_stmt_arena_ptr;
if (save_character_set_client)
thd->update_charset(save_character_set_client, save_collation);
DBUG_RETURN(res);
}

/**
Expand Down Expand Up @@ -2834,106 +2859,45 @@ static bool fix_and_check_vcol_expr(THD *thd, TABLE *table,

static Virtual_column_info *
unpack_vcol_info_from_frm(THD *thd, MEM_ROOT *mem_root, TABLE *table,
const uchar *expr_str, size_t expr_str_length,
Virtual_column_info *vcol, bool *error_reported)
String *expr_str, Virtual_column_info **vcol_ptr,
bool *error_reported)
{
char *vcol_expr_str;
int str_len;
CHARSET_INFO *save_character_set_client, *save_collation;
Query_arena *backup_stmt_arena_ptr;
Query_arena backup_arena;
Query_arena *vcol_arena= 0;
Create_field vcol_storage; // placeholder for vcol_info
Parser_state parser_state;
Virtual_column_info *vcol_info= 0;
Virtual_column_info *vcol= *vcol_ptr, *vcol_info= 0;
LEX *old_lex= thd->lex;
LEX lex;
bool error;
DBUG_ENTER("unpack_vcol_info_from_frm");

save_character_set_client= thd->variables.character_set_client;
save_collation= thd->variables.collation_connection;
backup_stmt_arena_ptr= thd->stmt_arena;

/*
Step 1: Construct the input string for the parser.
The string to be parsed has to be of the following format:
"PARSE_VCOL_EXPR (<expr_string_from_frm>)".
*/
DBUG_ASSERT(vcol->expr == NULL);

if (!(vcol_expr_str= (char*) alloc_root(mem_root,
expr_str_length +
parse_vcol_keyword.length + 3)))
DBUG_RETURN(0);
memcpy(vcol_expr_str, parse_vcol_keyword.str, parse_vcol_keyword.length);
str_len= parse_vcol_keyword.length;
vcol_expr_str[str_len++]= '(';
memcpy(vcol_expr_str + str_len, expr_str, expr_str_length);
str_len+= expr_str_length;
vcol_expr_str[str_len++]= ')';
vcol_expr_str[str_len++]= 0;

if (parser_state.init(thd, vcol_expr_str, str_len))
goto err;

/*
Step 2: Setup thd for parsing.
*/
vcol_arena= table->expr_arena;
if (!vcol_arena)
{
/*
We need to use CONVENTIONAL_EXECUTION here to ensure that
any new items created by fix_fields() are not reverted.
*/
Query_arena expr_arena(mem_root,
Query_arena::STMT_CONVENTIONAL_EXECUTION);
if (!(vcol_arena= (Query_arena *) alloc_root(mem_root,
sizeof(Query_arena))))
goto err;
*vcol_arena= expr_arena;
table->expr_arena= vcol_arena;
}
thd->set_n_backup_active_arena(vcol_arena, &backup_arena);
thd->stmt_arena= vcol_arena;
if (parser_state.init(thd, expr_str->c_ptr(), expr_str->length()))
goto end;

if (init_lex_with_single_table(thd, table, &lex))
goto err;
goto end;

lex.parse_vcol_expr= TRUE;
lex.parse_vcol_expr= true;
lex.last_field= &vcol_storage;

/*
Step 3: Use the parser to build an Item object from vcol_expr_str.
*/
if (vcol->utf8)
{
thd->update_charset(&my_charset_utf8mb4_general_ci,
table->s->table_charset);
}
error= parse_sql(thd, &parser_state, NULL);
if (error)
goto err;
goto end;

vcol_storage.vcol_info->stored_in_db= vcol->stored_in_db;
vcol_storage.vcol_info->name= vcol->name;
vcol_storage.vcol_info->utf8= vcol->utf8;
if (!fix_and_check_vcol_expr(thd, table, vcol_storage.vcol_info))
{
vcol_info= vcol_storage.vcol_info; // Expression ok
*vcol_ptr= vcol_info= vcol_storage.vcol_info; // Expression ok
DBUG_ASSERT(vcol_info->expr);
goto end;
}
*error_reported= TRUE;

err:
thd->free_items();
end:
thd->stmt_arena= backup_stmt_arena_ptr;
if (vcol_arena)
thd->restore_active_arena(vcol_arena, &backup_arena);
end_lex_with_single_table(thd, table, old_lex);
if (vcol->utf8)
thd->update_charset(save_character_set_client, save_collation);

DBUG_RETURN(vcol_info);
}
Expand Down

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