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MDEV-33281 Implement optimizer hints

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- Using Lex_ident_sys to scan identifiers, like the SQL parser does.

  This fixes handling of double-quote-delimited and backtick-delimited identifiers,
  as well as handling of non-ASCII identifiers.

  Unescaping and converting from the client character set to the system
  character set is now done using Lex_ident_cli_st and Lex_ident_sys,
  like it's done in the SQL tokenizer/parser.
  Adding helper methods to_ident_cli() and to_ident_sys()
  in Optimizer_hint_parser::Token.

- Fixing the hint parser to report a syntax error when an empty identifiers:
    SELECT /*+ BKA(``) */ * FROM t1;

- Moving a part of the code from opt_hints_parser.h to opt_hints_parser.cc

  Moving these method definitions:
  - Optimizer_hint_tokenizer::find_keyword()
  - Optimizer_hint_tokenizer::get_token()

  to avoid huge pieces of the code in the header file.

- A Lex_ident_cli_st cleanup
  Fixing a few Lex_ident_cli_st methods to return Lex_ident_cli_st &
  instead of void, to use them easier in the caller code.

- Fixing the hint parser to display the correct line number

  Adding a new data type Lex_comment_st
  (a combination of LEX_CSTRING and a line number)
  Using it in sql_yacc.yy

- Getting rid of redundant dependencies on sql_hints_parser.h

  Moving void LEX::resolve_optimizer_hints() from sql_lex.h to sql_lex.cc

  Adding a class Optimizer_hint_parser_output, deriving from
  Optimizer_hint_parser::Hint_list. Fixing the hint parser to
  return a pointer to an allocated instance of Optimizer_hint_parser_output
  rather than an instance of Optimizer_hint_parser::Hint_list.
  This allows to use a forward declaration of Optimizer_hint_parser_output
  in sql_lex.h and thus avoid dependencies on sql_hints_parser.h.
This commit is contained in:
Alexander Barkov
2024-07-15 14:29:47 +04:00
committed by Oleg Smirnov
parent 877e4a386c
commit bd30c796fa
10 changed files with 257 additions and 147 deletions
Download Patch File Download Diff File Expand all files Collapse all files

112
sql/opt_hints_parser.h
View File

@@ -18,7 +18,7 @@
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
*/
#include "lex_ident_sys.h"
#include "simple_tokenizer.h"
#include "sql_list.h"
#include "simple_parser.h"
@@ -76,40 +76,6 @@ public:
tIDENT
};
protected:
TokenID find_keyword(const LEX_CSTRING &str)
{
switch (str.length)
{
case 3:
if ("BKA"_Lex_ident_column.streq(str)) return TokenID::keyword_BKA;
if ("BNL"_Lex_ident_column.streq(str)) return TokenID::keyword_BNL;
if ("MRR"_Lex_ident_column.streq(str)) return TokenID::keyword_MRR;
break;
case 6:
if ("NO_BKA"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_BKA;
if ("NO_BNL"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_BNL;
if ("NO_ICP"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_ICP;
if ("NO_MRR"_Lex_ident_column.streq(str)) return TokenID::keyword_NO_MRR;
break;
case 7:
if ("QB_NAME"_Lex_ident_column.streq(str))
return TokenID::keyword_QB_NAME;
break;
case 21:
if ("NO_RANGE_OPTIMIZATION"_Lex_ident_column.streq(str))
return TokenID::keyword_NO_RANGE_OPTIMIZATION;
break;
}
return TokenID::tIDENT;
}
public:
class Token: public Lex_cstring
{
protected:
@@ -132,32 +98,9 @@ public:
}
};
Token get_token(CHARSET_INFO *cs)
{
get_spaces();
if (eof())
return Token(Lex_cstring(m_ptr, m_ptr), TokenID::tEOF);
const char head= m_ptr[0];
if (head == '`' || head=='"')
{
const Token_with_metadata delimited_ident= get_quoted_string();
if (delimited_ident.length)
return Token(delimited_ident, TokenID::tIDENT);
}
const Token_with_metadata ident= get_ident();
if (ident.length)
return Token(ident, ident.m_extended_chars ?
TokenID::tIDENT : find_keyword(ident));
if (!get_char(','))
return Token(Lex_cstring(m_ptr - 1, 1), TokenID::tCOMMA);
if (!get_char('@'))
return Token(Lex_cstring(m_ptr - 1, 1), TokenID::tAT);
if (!get_char('('))
return Token(Lex_cstring(m_ptr - 1, 1), TokenID::tLPAREN);
if (!get_char(')'))
return Token(Lex_cstring(m_ptr - 1, 1), TokenID::tRPAREN);
return Token(Lex_cstring(m_ptr, m_ptr), TokenID::tNULL);
}
protected:
Token get_token(CHARSET_INFO *cs);
static TokenID find_keyword(const LEX_CSTRING &str);
};
@@ -167,6 +110,7 @@ class Optimizer_hint_parser: public Optimizer_hint_tokenizer,
private:
Token m_look_ahead_token;
THD *m_thd;
const char *m_start;
bool m_syntax_error;
bool m_fatal_error;
public:
@@ -174,6 +118,7 @@ public:
:Optimizer_hint_tokenizer(cs, hint),
m_look_ahead_token(get_token(cs)),
m_thd(thd),
m_start(hint.str),
m_syntax_error(false),
m_fatal_error(false)
{ }
@@ -187,6 +132,24 @@ public:
m_fatal_error= true;
return false;
}
// Calculate the line number inside the whole hint
uint lineno(const char *ptr) const
{
DBUG_ASSERT(m_start <= ptr);
DBUG_ASSERT(ptr <= m_end);
uint lineno= 0;
for ( ; ptr >= m_start; ptr--)
{
if (*ptr == '\n')
lineno++;
}
return lineno;
}
uint lineno() const
{
return lineno(m_ptr);
}
TokenID look_ahead_token_id() const
{
return is_error() ? TokenID::tNULL : m_look_ahead_token.id();
@@ -249,7 +212,7 @@ public:
bool parse_token_list(THD *thd); // For debug purposes
void push_warning_syntax_error(THD *thd);
void push_warning_syntax_error(THD *thd, uint lineno);
private:
@@ -280,6 +243,18 @@ private:
{
public:
using TOKEN::TOKEN;
Lex_ident_cli_st to_ident_cli() const
{
Lex_ident_cli_st cli;
if (length >= 2 && (str[0] == '`' || str[0] == '"'))
return cli.set_ident_quoted(str + 1, length - 2, true, str[0]);
return cli.set_ident(str, length, true);
}
Lex_ident_sys to_ident_sys(THD *thd) const
{
const Lex_ident_cli_st cli= to_ident_cli();
return Lex_ident_sys(thd, &cli);
}
};
class LParen: public TOKEN<PARSER, TokenID::tLPAREN>
@@ -627,4 +602,17 @@ public:
};
/*
This wrapper class is needed to use a forward declaration in sql_lex.h
instead of including the entire opt_hints_parser.h.
(forward declarations of qualified nested classes are not possible in C++)
*/
class Optimizer_hint_parser_output: public Optimizer_hint_parser::Hint_list
{
public:
using Hint_list::Hint_list;
};
#endif // OPT_HINTS_PARSER