Description:
After reading bug report of MysqlBug39268 (http://bugs.mysql.com/bug.php?id=39268), I feel that if we can provide startTransaction() function with a NdbDictionary::Table parameter as hint, we can get a better performance, and we can get the NdbDictionary::Table parameter from the parameter of getNdbOperation() function.
According to this rule, I check the source code of mysql-cluster-gpl-7.1.9a, and I find some code fragments which are the same situation as mysqlbug39268. I think these code fragments will cause performance problem, and they should be patched in the same way as mysqlbug39268.
The places I find are:
mysql-cluster-gpl-7.1.9a/storage/ndb/tools/restore/consumer_restore.cpp : 917
NdbTransaction * trans= m_ndb->startTransaction();
mysql-cluster-gpl-7.1.9a/storage/ndb/tools/restore/consumer_restore.cpp : 924
NdbOperation * op= trans->getNdbOperation(ndbtab);
NdbTransaction * trans= m_ndb->startTransaction();
if (!trans)
{
err << NDB_APPLY_TABLE << ": "
<< m_ndb->getNdbError() << endl;
return false;
}
NdbOperation * op= trans->getNdbOperation(ndbtab);
==============================================================================
mysql-cluster-gpl-7.1.9a/storage/ndb/tools/restore/consumer_restore.cpp : 2177
NdbTransaction * trans = m_ndb->startTransaction();
mysql-cluster-gpl-7.1.9a/storage/ndb/tools/restore/consumer_restore.cpp : 2191
NdbOperation * op = trans->getNdbOperation(table);
NdbTransaction * trans = m_ndb->startTransaction();
if (trans == NULL)
{
errobj = m_ndb->getNdbError();
if (errobj.status == NdbError::TemporaryError)
{
goto retry;
}
err << "Cannot start transaction: " << errobj << endl;
exitHandler();
} // if
TransGuard g(trans);
const NdbDictionary::Table * table = get_table(tup.m_table->m_dictTable);
NdbOperation * op = trans->getNdbOperation(table);
===============================================================================
ysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 1732
if ((trans= ndb->startTransaction()) == 0)
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 1782
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
false positive:
while (1)
{
if ((trans= ndb->startTransaction()) == 0)
goto err;
{
NdbOperation *op= 0;
int r= 0;
/* read the bitmap exlusive */
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
DBUG_ASSERT(r == 0);
r|= op->readTupleExclusive();
DBUG_ASSERT(r == 0);
/* db */
ndb_pack_varchar(col[SCHEMA_DB_I], tmp_buf, db, strlen(db));
r|= op->equal(SCHEMA_DB_I, tmp_buf);
DBUG_ASSERT(r == 0);
/* name */
ndb_pack_varchar(col[SCHEMA_NAME_I], tmp_buf, table_name,
strlen(table_name));
r|= op->equal(SCHEMA_NAME_I, tmp_buf);
DBUG_ASSERT(r == 0);
/* slock */
r|= op->getValue(SCHEMA_SLOCK_I, (char*)slock.bitmap) == 0;
DBUG_ASSERT(r == 0);
}
if (trans->execute(NdbTransaction::NoCommit))
goto err;
if (opt_ndb_extra_logging > 19)
{
uint32 copy[SCHEMA_SLOCK_SIZE/4];
memcpy(copy, bitbuf, sizeof(copy));
bitmap_clear_bit(&slock, node_id);
sql_print_information("NDB: reply to %s.%s(%u/%u) from %x%x to %x%x",
db, table_name,
table_id, table_version,
copy[0], copy[1],
slock.bitmap[0],
slock.bitmap[1]);
}
else
{
bitmap_clear_bit(&slock, node_id);
}
{
NdbOperation *op= 0;
int r= 0;
/* now update the tuple */
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
DBUG_ASSERT(r == 0);
r|= op->updateTuple();
DBUG_ASSERT(r == 0);
================================================================================
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 1732
if ((trans= ndb->startTransaction()) == 0)
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 1739
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
while (1)
{
if ((trans= ndb->startTransaction()) == 0)
goto err;
{
NdbOperation *op= 0;
int r= 0;
/* read the bitmap exlusive */
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
DBUG_ASSERT(r == 0);
r|= op->readTupleExclusive();
DBUG_ASSERT(r == 0);
================================================================================
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 4057
NdbTransaction *trans= ndb->startTransaction();
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 4075
if ((_op= trans->getNdbOperation(reptab)) == NULL) abort();
NdbTransaction *trans= ndb->startTransaction();
if (trans == NULL)
{
ndberror= ndb->getNdbError();
break;
}
NdbRecAttr *col_binlog_type_rec_attr[2];
NdbRecAttr *col_conflict_fn_rec_attr[2]= {NULL, NULL};
uint32 ndb_binlog_type[2];
const uint sz= 256;
char ndb_conflict_fn_buf[2*sz];
char *ndb_conflict_fn[2]= {ndb_conflict_fn_buf, ndb_conflict_fn_buf+sz};
NdbOperation *op[2];
uint32 i, id= 0;
for (i= 0; i < 2; i++)
{
NdbOperation *_op;
DBUG_PRINT("info", ("reading[%u]: %s,%s,%u", i, db, table_name, id));
if ((_op= trans->getNdbOperation(reptab)) == NULL) abort();
===============================================================================
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 2121
if ((trans= ndb->startTransaction()) == 0)
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_binlog.cc : 2127
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
if ((trans= ndb->startTransaction()) == 0)
goto err;
while (1)
{
NdbOperation *op= 0;
int r= 0;
r|= (op= trans->getNdbOperation(ndbtab)) == 0;
===============================================================================
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_lock_ext.h : 63
if ((trans= ndb->startTransaction()) == 0)
mysql-cluster-gpl-7.1.9a/sql/ha_ndbcluster_lock_ext.h : 70
trans= ndb->startTransaction();
if (trans == NULL)
{
ndb_error= ndb->getNdbError();
goto error_handler;
}
op= trans->getNdbOperation(ndbtab);
How to repeat:
code review
Suggested fix:
call startTransaction() with the parameter of getNdbOperation(), and call getNdbOperation() with no parameter.
