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malone-at-workmalone-at-work
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vef: add stateful TypeDecoder
TypeDecoder is an object that allocates buffers and VDF structs once per expression and reuses them across rows. It writes directly into the caller-provided String *out (following MySQL's val_str(String *buf) convention) and sets it to point at the scratch buffer — zero copies on the hot path. The returned pointer is valid until the next decode() call, which is sufficient for the protocol send path. val_external_str on both Field and Item now fills the buffer argument and returns it, consistent with val_str. One-shot decodes outside the row-reading path (e.g. Item_string::print()) use DecodeStringUncached. For the mem_root selection on Field: regular tables (NO_TMP_TABLE) use TABLE::mem_root, giving the decoder the same lifetime as its Field clone and avoiding orphaned allocations on the share. All temp table variants use TABLE_SHARE::mem_root because close_tmp_table() asserts TABLE::mem_root is empty — this covers both INTERNAL_TMP_TABLE and derived/CTE tables, which are initialized as INTERNAL_TMP_TABLE but overwritten to NON_TRANSACTIONAL_TMP_TABLE by sql_derived.cc.
1 parent 33807da commit bad2dea

16 files changed

Lines changed: 440 additions & 150 deletions

‎mysql-test/suite/villagesql/ps/r/ps_decode_context_reuse_complex.result‎

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
CREATE TABLE t1 (id INT, c1 COMPLEX, c2 COMPLEX);
2+
INSERT INTO t1 VALUES (1,'(1.0,2.0)','(3.0,4.0)'),(2,'(5.0,6.0)','(7.0,8.0)'),(3,'(1.0,2.0)','(5.0,6.0)');
3+
PREPARE stmt FROM 'SELECT vsql_complex.complex_add(c1, c2) AS result FROM t1 WHERE id = ?';
4+
SET @p = 1;
5+
EXECUTE stmt USING @p;
6+
result
7+
(4,6)
8+
SET @p = 2;
9+
EXECUTE stmt USING @p;
10+
result
11+
(12,14)
12+
SET @p = 3;
13+
EXECUTE stmt USING @p;
14+
result
15+
(6,8)
16+
DEALLOCATE PREPARE stmt;
17+
DROP TABLE t1;

‎mysql-test/suite/villagesql/ps/t/ps_decode_context_reuse_complex.test‎

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,31 @@
1+
# Test that TypeDecoder on Item_func is correctly reset between PS
2+
# re-executions. TypeDecoder is lazily allocated on thd->mem_root for
3+
# Items (VDF result expressions). Item::cleanup() nulls type_decoder_
4+
# between executions so the next execution re-allocates on the fresh
5+
# thd->mem_root. Without this reset, re-execution would use a dangling
6+
# pointer from the prior execution's mem_root.
7+
8+
--source include/villagesql/install_complex_extension.inc
9+
10+
CREATE TABLE t1 (id INT, c1 COMPLEX, c2 COMPLEX);
11+
INSERT INTO t1 VALUES (1,'(1.0,2.0)','(3.0,4.0)'),(2,'(5.0,6.0)','(7.0,8.0)'),(3,'(1.0,2.0)','(5.0,6.0)');
12+
13+
# Execute the same prepared statement three times with different parameter
14+
# values. Each execution must decode the COMPLEX result correctly using a
15+
# fresh TypeDecoder, not a stale pointer from a prior execution.
16+
PREPARE stmt FROM 'SELECT vsql_complex.complex_add(c1, c2) AS result FROM t1 WHERE id = ?';
17+
18+
SET @p = 1;
19+
EXECUTE stmt USING @p;
20+
21+
SET @p = 2;
22+
EXECUTE stmt USING @p;
23+
24+
SET @p = 3;
25+
EXECUTE stmt USING @p;
26+
27+
DEALLOCATE PREPARE stmt;
28+
29+
DROP TABLE t1;
30+
31+
--source include/villagesql/uninstall_complex_extension.inc

‎sql/dd/dd_table.cc‎

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -358,8 +358,11 @@ static void prepare_default_value_string(uchar *buf, TABLE *table,
358358
// For BINARY(0) and VARBINARY type with empty string as default value.
359359
f->val_str(&type);
360360
} else {
361-
// VillageSQL: val_external_str handles both custom and regular types
362-
f->val_external_str(&type);
361+
// VillageSQL: val_external_str handles both custom and regular types.
362+
// Copy if val_str returned a different pointer than the buffer we passed.
363+
if (const String *res = f->val_external_str(&type);
364+
res != nullptr && res != &type)
365+
type.copy(*res);
363366
}
364367

365368
if (type.length()) {

‎sql/field.cc‎

Lines changed: 15 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -10619,31 +10619,27 @@ const char *get_field_name_or_expression(THD *thd, const Field *field) {
1061910619
String *Field::val_external_str(String *buf) const {
1062010620
if (!has_type_context()) return val_str(buf);
1062110621

10622-
// Get the encoded data directly from the field
10623-
const uchar *encoded_data = data_ptr();
10624-
size_t encoded_length = data_length();
10625-
1062610622
bool is_valid = true;
10627-
if (villagesql::DecodeString(*get_type_context(), encoded_data,
10628-
encoded_length, *current_thd->mem_root, buf,
10629-
is_valid) &&
10630-
!is_valid) {
10631-
THD *thd = current_thd;
10632-
if (!thd->lex->is_ignore() && thd->is_strict_mode()) {
10633-
const ErrConvString errmsg(pointer_cast<const char *>(encoded_data),
10634-
encoded_length, &my_charset_bin);
10635-
const Diagnostics_area *da = thd->get_stmt_da();
10636-
push_warning_printf(thd, Sql_condition::SL_WARNING,
10637-
ER_TRUNCATED_WRONG_VALUE_FOR_FIELD,
10638-
ER_THD(thd, ER_TRUNCATED_WRONG_VALUE_FOR_FIELD),
10639-
get_type_context()->type_name().c_str(), errmsg.ptr(),
10640-
this->field_name, da->current_row_for_condition());
10623+
if (!villagesql::DecodeStringForField(this, buf, is_valid)) {
10624+
if (!is_valid) {
10625+
THD *thd = current_thd;
10626+
if (!thd->lex->is_ignore() && thd->is_strict_mode()) {
10627+
const uchar *encoded_data = data_ptr();
10628+
size_t encoded_length = data_length();
10629+
const ErrConvString errmsg(pointer_cast<const char *>(encoded_data),
10630+
encoded_length, &my_charset_bin);
10631+
const Diagnostics_area *da = thd->get_stmt_da();
10632+
push_warning_printf(
10633+
thd, Sql_condition::SL_WARNING, ER_TRUNCATED_WRONG_VALUE_FOR_FIELD,
10634+
ER_THD(thd, ER_TRUNCATED_WRONG_VALUE_FOR_FIELD),
10635+
get_type_context()->type_name().c_str(), errmsg.ptr(),
10636+
this->field_name, da->current_row_for_condition());
10637+
}
1064110638
}
1064210639
// OOMs will just return nullptr, but have called my_error.
1064310640
return nullptr;
1064410641
}
1064510642

10646-
// Success: the decoded string is in buf.
1064710643
return buf;
1064810644
}
1064910645

‎sql/field.h‎

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -64,6 +64,7 @@
6464
#include "villagesql/schema/descriptor/type_context.h"
6565

6666
namespace villagesql {
67+
class TypeDecoder;
6768
class TypeEncoder;
6869
} // namespace villagesql
6970

@@ -1891,6 +1892,8 @@ class Field {
18911892
private:
18921893
const villagesql::TypeContext *custom_type{nullptr};
18931894
villagesql::TypeEncoder *type_encoder_{nullptr};
1895+
// mutable: lazily initialised by the const val_external_str() path.
1896+
mutable villagesql::TypeDecoder *type_decoder_{nullptr};
18941897

18951898
public:
18961899
const villagesql::TypeContext *get_type_context() const {
@@ -1903,6 +1906,11 @@ class Field {
19031906
void set_type_encoder(villagesql::TypeEncoder *encoder) {
19041907
type_encoder_ = encoder;
19051908
}
1909+
1910+
villagesql::TypeDecoder *get_type_decoder() const { return type_decoder_; }
1911+
void set_type_decoder(villagesql::TypeDecoder *decoder) const {
1912+
type_decoder_ = decoder;
1913+
}
19061914
};
19071915

19081916
/**

‎sql/item.cc‎

Lines changed: 5 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -290,17 +290,8 @@ String *Item::val_external_str(String *str) {
290290
String *binary_data = val_str(str);
291291
if (!has_type_context() || null_value) return binary_data;
292292

293-
// Decode using TypeContext's to_string function
294293
bool is_valid = true;
295-
if (villagesql::DecodeString(
296-
*get_type_context(), pointer_cast<const uchar *>(binary_data->ptr()),
297-
binary_data->length(), *current_thd->mem_root, str, is_valid)) {
298-
if (!is_valid) {
299-
// Invalid custom type data - set null and return nullptr
300-
null_value = true;
301-
return nullptr;
302-
}
303-
// OOM or other error (my_error already called)
294+
if (!villagesql::DecodeStringForItem(this, *binary_data, str, is_valid)) {
304295
null_value = true;
305296
return nullptr;
306297
}
@@ -3631,12 +3622,11 @@ void Item_string::print(const THD *, String *str,
36313622
// Custom types: decode binary representation to string format.
36323623
if (has_type_context()) {
36333624
str->append('\'');
3634-
String decoded;
36353625
bool is_valid;
3636-
if (!villagesql::DecodeString(
3637-
*get_type_context(), (const uchar *)str_value.ptr(),
3638-
str_value.length(), *current_thd->mem_root, &decoded, is_valid)) {
3639-
str->append(decoded);
3626+
String decoded_buf;
3627+
if (villagesql::DecodeStringUncached(get_type_context(), str_value,
3628+
&decoded_buf, is_valid)) {
3629+
str->append(decoded_buf);
36403630
}
36413631
str->append('\'');
36423632
return;

‎sql/item.h‎

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -80,6 +80,7 @@
8080
#include "villagesql/include/item_helpers.h"
8181

8282
namespace villagesql {
83+
class TypeDecoder;
8384
class TypeEncoder;
8485
} // namespace villagesql
8586

@@ -1284,6 +1285,7 @@ class Item : public Parse_tree_node {
12841285
virtual void cleanup() {
12851286
marker = MARKER_NONE;
12861287
type_encoder_ = nullptr;
1288+
type_decoder_ = nullptr;
12871289
}
12881290
/**
12891291
Called when an item has been removed, can be used to notify external
@@ -3756,6 +3758,7 @@ class Item : public Parse_tree_node {
37563758
protected:
37573759
const villagesql::TypeContext *custom_type{nullptr};
37583760
villagesql::TypeEncoder *type_encoder_{nullptr};
3761+
villagesql::TypeDecoder *type_decoder_{nullptr};
37593762

37603763
public:
37613764
virtual const villagesql::TypeContext *get_type_context() const {
@@ -3767,6 +3770,10 @@ class Item : public Parse_tree_node {
37673770
void set_type_encoder(villagesql::TypeEncoder *encoder) {
37683771
type_encoder_ = encoder;
37693772
}
3773+
villagesql::TypeDecoder *get_type_decoder() const { return type_decoder_; }
3774+
void set_type_decoder(villagesql::TypeDecoder *decoder) {
3775+
type_decoder_ = decoder;
3776+
}
37703777
};
37713778

37723779
/**

‎sql/key.cc‎

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -323,8 +323,11 @@ void field_unpack(String *to, Field *field, uint max_length, bool prefix_key) {
323323
return;
324324
}
325325
const CHARSET_INFO *cs = field->charset();
326-
// VillageSQL: val_external_str handles both custom and regular types
327-
field->val_external_str(&tmp);
326+
// VillageSQL: val_external_str handles both custom and regular types.
327+
// For custom types the return value is a different pointer, so copy it.
328+
if (const String *res = field->val_external_str(&tmp);
329+
res != nullptr && res != &tmp)
330+
tmp.copy(*res);
328331
/*
329332
For BINARY(N) strip trailing zeroes to make
330333
the error message nice-looking

‎sql/sql_show.cc‎

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1710,8 +1710,11 @@ static bool print_default_clause(THD *thd, Field *field, String *def_value,
17101710
type.length(length + 1);
17111711
quoted = false;
17121712
} else {
1713-
// VillageSQL: val_external_str handles both custom and regular types
1714-
field->val_external_str(&type);
1713+
// VillageSQL: val_external_str handles both custom and regular types.
1714+
// For custom types the return value is a different pointer, so copy it.
1715+
if (const String *res = field->val_external_str(&type);
1716+
res != nullptr && res != &type)
1717+
type.copy(*res);
17151718
}
17161719

17171720
if (type.length()) {

‎villagesql/types/CMakeLists.txt‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,7 @@
1414
# along with this program; if not, see <https://www.gnu.org/licenses/>.
1515

1616
SET(VILLAGESQL_TYPES_SOURCES
17+
type_decoder.cc
1718
type_encoder.cc
1819
type_op.cc
1920
util.cc

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