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Core/DBLayer: Optimized prepared statement query results by eliminating unneeded buffer copies

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* Improved error logs for using incorrect Field getters to also include table name, field name and field index.
This commit is contained in:
Shauren
2015-08-26 17:00:26 +02:00
parent 614b5832ba
commit 65dbc7082a
5 changed files with 130 additions and 94 deletions
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118
src/server/database/Database/QueryResult.cpp
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@@ -26,7 +26,10 @@ _result(result),
_fields(fields)
{
_currentRow = new Field[_fieldCount];
ASSERT(_currentRow);
#ifdef TRINITY_DEBUG
for (uint32 i = 0; i < _fieldCount; i++)
_currentRow[i].SetMetadata(&_fields[i], i);
#endif
}
PreparedResultSet::PreparedResultSet(MYSQL_STMT* stmt, MYSQL_RES *result, uint64 rowCount, uint32 fieldCount) :
@@ -35,11 +38,11 @@ m_rowPosition(0),
m_fieldCount(fieldCount),
m_rBind(NULL),
m_stmt(stmt),
m_res(result),
m_metadataResult(result),
m_isNull(NULL),
m_length(NULL)
{
if (!m_res)
if (!m_metadataResult)
return;
if (m_stmt->bind_result_done)
@@ -66,50 +69,44 @@ m_length(NULL)
return;
}
//- This is where we prepare the buffer based on metadata
uint32 i = 0;
MYSQL_FIELD* field = mysql_fetch_field(m_res);
while (field)
{
size_t size = Field::SizeForType(field);
m_rowCount = mysql_stmt_num_rows(m_stmt);
m_rBind[i].buffer_type = field->type;
m_rBind[i].buffer = malloc(size);
memset(m_rBind[i].buffer, 0, size);
//- This is where we prepare the buffer based on metadata
MYSQL_FIELD* field = mysql_fetch_fields(m_metadataResult);
for (uint32 i = 0; i < m_fieldCount; ++i)
{
size_t size = Field::SizeForType(&field[i]);
m_rBind[i].buffer_type = field[i].type;
m_rBind[i].buffer = new char[size * m_rowCount];
m_rBind[i].buffer_length = size;
m_rBind[i].length = &m_length[i];
m_rBind[i].is_null = &m_isNull[i];
m_rBind[i].error = NULL;
m_rBind[i].is_unsigned = field->flags & UNSIGNED_FLAG;
++i;
field = mysql_fetch_field(m_res);
m_rBind[i].is_unsigned = field[i].flags & UNSIGNED_FLAG;
}
//- This is where we bind the bind the buffer to the statement
if (mysql_stmt_bind_result(m_stmt, m_rBind))
{
TC_LOG_WARN("sql.sql", "%s:mysql_stmt_bind_result, cannot bind result from MySQL server. Error: %s", __FUNCTION__, mysql_stmt_error(m_stmt));
delete[] m_rBind;
mysql_stmt_free_result(m_stmt);
CleanUp();
delete[] m_isNull;
delete[] m_length;
return;
}
m_rowCount = mysql_stmt_num_rows(m_stmt);
m_rows.resize(uint32(m_rowCount));
m_rows.resize(uint32(m_rowCount) * m_fieldCount);
while (_NextRow())
{
m_rows[uint32(m_rowPosition)] = new Field[m_fieldCount];
for (uint64 fIndex = 0; fIndex < m_fieldCount; ++fIndex)
for (uint32 fIndex = 0; fIndex < m_fieldCount; ++fIndex)
{
unsigned long buffer_length = m_rBind[fIndex].buffer_length;
unsigned long fetched_length = *m_rBind[fIndex].length;
if (!*m_rBind[fIndex].is_null)
m_rows[uint32(m_rowPosition)][fIndex].SetByteValue(m_rBind[fIndex].buffer,
m_rBind[fIndex].buffer_length,
m_rBind[fIndex].buffer_type,
*m_rBind[fIndex].length);
else
{
void* buffer = m_stmt->bind[fIndex].buffer;
switch (m_rBind[fIndex].buffer_type)
{
case MYSQL_TYPE_TINY_BLOB:
@@ -118,24 +115,42 @@ m_length(NULL)
case MYSQL_TYPE_BLOB:
case MYSQL_TYPE_STRING:
case MYSQL_TYPE_VAR_STRING:
m_rows[uint32(m_rowPosition)][fIndex].SetByteValue("",
m_rBind[fIndex].buffer_length,
m_rBind[fIndex].buffer_type,
*m_rBind[fIndex].length);
break;
default:
m_rows[uint32(m_rowPosition)][fIndex].SetByteValue(nullptr,
m_rBind[fIndex].buffer_length,
m_rBind[fIndex].buffer_type,
*m_rBind[fIndex].length);
// warning - the string will not be null-terminated if there is no space for it in the buffer
// when mysql_stmt_fetch returned MYSQL_DATA_TRUNCATED
// we cannot blindly null-terminate the data either as it may be retrieved as binary blob and not specifically a string
// in this case using Field::GetCString will result in garbage
// TODO: remove Field::GetCString and use boost::string_ref (currently proposed for TS as string_view, maybe in C++17)
if (fetched_length < buffer_length)
*((char*)buffer + fetched_length) = '\0';
break;
}
m_rows[uint32(m_rowPosition) * m_fieldCount + fIndex].SetByteValue(
buffer,
m_rBind[fIndex].buffer_type,
fetched_length);
// move buffer pointer to next part
m_stmt->bind[fIndex].buffer = (char*)buffer + buffer_length;
}
else
{
m_rows[uint32(m_rowPosition) * m_fieldCount + fIndex].SetByteValue(
nullptr,
m_rBind[fIndex].buffer_type,
*m_rBind[fIndex].length);
}
#ifdef TRINITY_DEBUG
m_rows[uint32(m_rowPosition) * m_fieldCount + fIndex].SetMetadata(&field[fIndex], fIndex);
#endif
}
m_rowPosition++;
}
m_rowPosition = 0;
/// All data is buffered, let go of mysql c api structures
CleanUp();
mysql_stmt_free_result(m_stmt);
}
ResultSet::~ResultSet()
@@ -145,8 +160,7 @@ ResultSet::~ResultSet()
PreparedResultSet::~PreparedResultSet()
{
for (uint32 i = 0; i < uint32(m_rowCount); ++i)
delete[] m_rows[i];
CleanUp();
}
bool ResultSet::NextRow()
@@ -215,18 +229,18 @@ void ResultSet::CleanUp()
void PreparedResultSet::CleanUp()
{
/// More of the in our code allocated sources are deallocated by the poorly documented mysql c api
if (m_res)
mysql_free_result(m_res);
if (m_metadataResult)
mysql_free_result(m_metadataResult);
FreeBindBuffer();
mysql_stmt_free_result(m_stmt);
if (m_rBind)
{
for (uint32 i = 0; i < m_fieldCount; ++i)
{
delete[]((char*)m_rBind[i].buffer);
m_rBind[i].buffer = nullptr;
}
delete[] m_rBind;
}
void PreparedResultSet::FreeBindBuffer()
{
for (uint32 i = 0; i < m_fieldCount; ++i)
free (m_rBind[i].buffer);
delete[] m_rBind;
m_rBind = nullptr;
}
}