INT32 _rtnIXScanner::resumeScan( BOOLEAN isReadOnly )
{
INT32 rc = SDB_OK ;
PD_TRACE_ENTRY ( SDB__RTNIXSCAN_RESUMESCAN ) ;
if ( !_indexCB )
{
PD_LOG ( PDERROR, "Failed to allocate memory for indexCB" ) ;
rc = SDB_OOM ;
goto error ;
}
if ( !_indexCB->isInitialized() )
{
rc = SDB_RTN_INDEX_NOTEXIST ;
goto done ;
}
if ( _indexCB->getFlag() != IXM_INDEX_FLAG_NORMAL )
{
rc = SDB_IXM_UNEXPECTED_STATUS ;
goto done ;
}
if ( !_init || _curIndexRID.isNull() || _savedObj.isEmpty() )
{
rc = SDB_OK ;
goto done ;
}
// for write mode, since we write _savedRID and _savedObj in advance, we
// don't do it here, so let's jump to done directly
if ( !isReadOnly )
{
goto done ;
}
// compare the historical index OID with the current index oid, to make
// sure the index is not changed during the time
if ( !_indexCB->isStillValid ( _indexOID ) ||
_indexLID != _indexCB->getLogicalID() )
{
rc = SDB_RTN_INDEX_NOTEXIST ;
goto done ;
}
{
// we assume _indexCB remains valid as long as the indexCBExtent still
// pointing to the same index oid (which should be unique against each
// index) because the storage unit should never be remapped in memory
// during its run
ixmExtent indexExtent ( _curIndexRID._extent, _su->index() ) ;
CHAR *dataBuffer = NULL ;
if ( indexExtent.isStillValid( _indexCB->getMBID() ) )
{
dataBuffer = indexExtent.getKeyData ( _curIndexRID._slot ) ;
}
if ( dataBuffer )
{
try
{
BSONObj curObj = ixmKey(dataBuffer).toBson() ;
// make sure key is the same
if ( curObj.shallowEqual(_savedObj) )
{
dmsRecordID onDiskRID = indexExtent.getRID (
_curIndexRID._slot ) ;
// make sure rid is the same
if ( onDiskRID == _savedRID )
{
// this means the last scaned record is still here, so let's
// reset _savedRID so that we'll call advance()
_savedRID.reset() ;
// if both key and rid are not changed, let's continue
goto done ;
}
}
}
catch ( std::exception &e )
{
PD_LOG ( PDERROR, "Failed to convert buffer to bson from "
"current rid: %d,%d: %s", _curIndexRID._extent,
_curIndexRID._slot, e.what() ) ;
rc = SDB_SYS ;
goto error ;
}
}
// when we get here, it means something changed and we need to
// relocateRID
// note relocateRID may relocate to the index that already read. However
// after advance() returning the RID we'll check if the index already has
// been read, so we should be save to not reset _savedRID
{
rc = relocateRID () ;
if ( rc )
{
PD_LOG ( PDERROR, "Failed to relocate RID, rc: %d", rc ) ;
goto error ;
}
}
}
done :
PD_TRACE_EXITRC ( SDB__RTNIXSCAN_RESUMESCAN, rc ) ;
return rc ;
error :
goto done ;
}
INT32 _rtnIXScanner::resumeScan( BOOLEAN isReadOnly )
{
INT32 rc = SDB_OK ;
PD_TRACE_ENTRY ( SDB__RTNIXSCAN_RESUMESCAN ) ;
if ( !_indexCB )
{
PD_LOG ( PDERROR, "Failed to allocate memory for indexCB" ) ;
rc = SDB_OOM ;
goto error ;
}
if ( !_indexCB->isInitialized() )
{
rc = SDB_RTN_INDEX_NOTEXIST ;
goto done ;
}
if ( _indexCB->getFlag() != IXM_INDEX_FLAG_NORMAL )
{
rc = SDB_IXM_UNEXPECTED_STATUS ;
goto done ;
}
if ( !_init || _curIndexRID.isNull() || _savedObj.isEmpty() )
{
rc = SDB_OK ;
goto done ;
}
if ( !isReadOnly )
{
goto done ;
}
if ( !_indexCB->isStillValid ( _indexOID ) ||
_indexLID != _indexCB->getLogicalID() )
{
rc = SDB_RTN_INDEX_NOTEXIST ;
goto done ;
}
{
ixmExtent indexExtent ( _curIndexRID._extent, _su->index() ) ;
CHAR *dataBuffer = NULL ;
if ( indexExtent.isStillValid( _indexCB->getMBID() ) )
{
dataBuffer = indexExtent.getKeyData ( _curIndexRID._slot ) ;
}
if ( dataBuffer )
{
try
{
BSONObj curObj = ixmKey(dataBuffer).toBson() ;
if ( curObj.shallowEqual(_savedObj) )
{
dmsRecordID onDiskRID = indexExtent.getRID (
_curIndexRID._slot ) ;
if ( onDiskRID == _savedRID )
{
_savedRID.reset() ;
goto done ;
}
}
}
catch ( std::exception &e )
{
PD_LOG ( PDERROR, "Failed to convert buffer to bson from "
"current rid: %d,%d: %s", _curIndexRID._extent,
_curIndexRID._slot, e.what() ) ;
rc = SDB_SYS ;
goto error ;
}
}
{
rc = relocateRID () ;
if ( rc )
{
PD_LOG ( PDERROR, "Failed to relocate RID, rc: %d", rc ) ;
goto error ;
}
}
}
done :
PD_TRACE_EXITRC ( SDB__RTNIXSCAN_RESUMESCAN, rc ) ;
return rc ;
error :
goto done ;
}