sqlite-parquet-vtable/parquet/parquet_cursor.cc

363 lines
11 KiB
C++

#include "parquet_cursor.h"
ParquetCursor::ParquetCursor(ParquetTable* table) {
this->table = table;
reader = NULL;
reset(std::vector<Constraint>());
}
bool ParquetCursor::nextRowGroup() {
// TODO: skip row groups that cannot satisfy the constraints
if((rowGroupId + 1) >= numRowGroups)
return false;
rowGroupStartRowId = rowId;
rowGroupId++;
rowGroupMetadata = reader->metadata()->RowGroup(rowGroupId);
rowsLeftInRowGroup = rowGroupMetadata->num_rows();
rowGroup = reader->RowGroup(rowGroupId);
for(unsigned int i = 0; i < scanners.size(); i++)
scanners[i] = NULL;
while(types.size() < (unsigned int)rowGroupMetadata->num_columns()) {
types.push_back(rowGroupMetadata->schema()->Column(0)->physical_type());
}
while(logicalTypes.size() < (unsigned int)rowGroupMetadata->num_columns()) {
logicalTypes.push_back(rowGroupMetadata->schema()->Column(0)->logical_type());
}
for(unsigned int i = 0; i < (unsigned int)rowGroupMetadata->num_columns(); i++) {
types[i] = rowGroupMetadata->schema()->Column(i)->physical_type();
logicalTypes[i] = rowGroupMetadata->schema()->Column(i)->logical_type();
}
for(unsigned int i = 0; i < colRows.size(); i++) {
colRows[i] = rowId;
}
return true;
}
// Return true if it is _possible_ that the current
// row satisfies the constraints. Only return false
// if it definitely does not.
bool ParquetCursor::currentRowSatisfiesFilter() {
for(unsigned int i = 0; i < constraints.size(); i++) {
int column = constraints[i].getColumn();
ensureColumn(column);
int op = constraints[i].getOperator();
if(op == IsNull) {
return isNull(column);
} else if(op == IsNotNull) {
return !isNull(column);
}
}
return true;
}
void ParquetCursor::next() {
start:
if(rowsLeftInRowGroup == 0) {
if(!nextRowGroup()) {
// put rowId over the edge so eof returns true
rowId++;
return;
}
}
rowsLeftInRowGroup--;
rowId++;
if(!currentRowSatisfiesFilter())
goto start;
}
int ParquetCursor::getRowId() {
return rowId;
}
bool ParquetCursor::eof() {
return rowId >= numRows;
}
void ParquetCursor::ensureColumn(int col) {
// -1 signals rowid, which is trivially available
if(col == -1)
return;
// need to ensure a scanner exists (and skip the # of rows in the rowgroup)
while((unsigned int)col >= scanners.size()) {
scanners.push_back(std::shared_ptr<parquet::Scanner>());
// If it doesn't exist, it's the rowId as of the last nextRowGroup call
colRows.push_back(rowGroupStartRowId);
colNulls.push_back(false);
colIntValues.push_back(0);
colDoubleValues.push_back(0);
colByteArrayValues.push_back(parquet::ByteArray());
}
if(scanners[col].get() == NULL) {
std::shared_ptr<parquet::ColumnReader> colReader = rowGroup->Column(col);
scanners[col] = parquet::Scanner::Make(colReader);
// TODO: potentially skip rows if rowsLeftInRowGroup != rowGroupMetadata->num_rows()
}
// Actually fetch a value, stash data in colRows, colNulls, colValues
if(colRows[col] != rowId) {
// We may need to skip some records, eg, a query like
// SELECT a WHERE b = 10
// may have read b, but skipped a until b matches the predicate.
bool wasNull = false;
while(colRows[col] + 1 < rowId) {
switch(types[col]) {
case parquet::Type::INT32:
{
parquet::Int32Scanner* s = (parquet::Int32Scanner*)scanners[col].get();
int rv = 0;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::FLOAT:
{
parquet::FloatScanner* s = (parquet::FloatScanner*)scanners[col].get();
float rv = 0;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::DOUBLE:
{
parquet::DoubleScanner* s = (parquet::DoubleScanner*)scanners[col].get();
double rv = 0;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::BYTE_ARRAY:
{
parquet::ByteArrayScanner* s = (parquet::ByteArrayScanner*)scanners[col].get();
parquet::ByteArray ba;
s->NextValue(&ba, &wasNull);
break;
}
case parquet::Type::INT96:
{
parquet::Int96Scanner* s = (parquet::Int96Scanner*)scanners[col].get();
parquet::Int96 rv;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::INT64:
{
parquet::Int64Scanner* s = (parquet::Int64Scanner*)scanners[col].get();
long rv = 0;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::BOOLEAN:
{
parquet::BoolScanner* s = (parquet::BoolScanner*)scanners[col].get();
bool rv = false;
s->NextValue(&rv, &wasNull);
break;
}
case parquet::Type::FIXED_LEN_BYTE_ARRAY:
{
parquet::FixedLenByteArrayScanner* s = (parquet::FixedLenByteArrayScanner*)scanners[col].get();
parquet::FixedLenByteArray flba;
s->NextValue(&flba, &wasNull);
break;
}
default:
// Should be impossible to get here as we should have forbidden this at
// CREATE time -- maybe file changed underneath us?
std::ostringstream ss;
ss << __FILE__ << ":" << __LINE__ << ": column " << col << " has unsupported type: " <<
parquet::TypeToString(types[col]);
throw std::invalid_argument(ss.str());
break;
}
colRows[col]++;
}
colRows[col] = rowId;
wasNull = false;
switch(types[col]) {
case parquet::Type::INT32:
{
parquet::Int32Scanner* s = (parquet::Int32Scanner*)scanners[col].get();
int rv = 0;
if(s->NextValue(&rv, &wasNull)) {
colIntValues[col] = rv;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::FLOAT:
{
parquet::FloatScanner* s = (parquet::FloatScanner*)scanners[col].get();
float rv = 0;
if(s->NextValue(&rv, &wasNull)) {
colDoubleValues[col] = rv;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::DOUBLE:
{
parquet::DoubleScanner* s = (parquet::DoubleScanner*)scanners[col].get();
double rv = 0;
if(s->NextValue(&rv, &wasNull)) {
colDoubleValues[col] = rv;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::BYTE_ARRAY:
{
parquet::ByteArrayScanner* s = (parquet::ByteArrayScanner*)scanners[col].get();
if(!s->NextValue(&colByteArrayValues[col], &wasNull)) {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::INT96:
{
// INT96 tracks a date with nanosecond precision, convert to ms since epoch.
// ...see https://github.com/apache/parquet-format/pull/49 for more
//
// First 8 bytes: nanoseconds into the day
// Last 4 bytes: Julian day
// To get nanoseconds since the epoch:
// (julian_day - 2440588) * (86400 * 1000 * 1000 * 1000) + nanoseconds
parquet::Int96Scanner* s = (parquet::Int96Scanner*)scanners[col].get();
parquet::Int96 rv;
rv.value[0] = 0;
rv.value[1] = 0;
rv.value[2] = 0;
if(s->NextValue(&rv, &wasNull)) {
__int128 ns = rv.value[0] + ((unsigned long)rv.value[1] << 32);
__int128 julianDay = rv.value[2];
__int128 nsSinceEpoch = (julianDay - 2440588);
nsSinceEpoch *= 86400;
nsSinceEpoch *= 1000 * 1000 * 1000;
nsSinceEpoch += ns;
nsSinceEpoch /= 1000000;
colIntValues[col] = nsSinceEpoch;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::INT64:
{
parquet::Int64Scanner* s = (parquet::Int64Scanner*)scanners[col].get();
long rv = 0;
if(s->NextValue(&rv, &wasNull)) {
colIntValues[col] = rv;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::BOOLEAN:
{
parquet::BoolScanner* s = (parquet::BoolScanner*)scanners[col].get();
bool rv = false;
if(s->NextValue(&rv, &wasNull)) {
colIntValues[col] = rv ? 1 : 0;
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
case parquet::Type::FIXED_LEN_BYTE_ARRAY:
{
parquet::FixedLenByteArrayScanner* s = (parquet::FixedLenByteArrayScanner*)scanners[col].get();
parquet::FixedLenByteArray flba;
if(s->NextValue(&flba, &wasNull)) {
colByteArrayValues[col].ptr = flba.ptr;
// TODO: cache this
colByteArrayValues[col].len = rowGroupMetadata->schema()->Column(col)->type_length();
} else {
throw std::invalid_argument("unexpectedly lacking a next value");
}
break;
}
default:
// Should be impossible to get here as we should have forbidden this at
// CREATE time -- maybe file changed underneath us?
std::ostringstream ss;
ss << __FILE__ << ":" << __LINE__ << ": column " << col << " has unsupported type: " <<
parquet::TypeToString(types[col]);
throw std::invalid_argument(ss.str());
break;
}
colNulls[col] = wasNull;
}
}
bool ParquetCursor::isNull(int col) {
// -1 is rowid, which is trivially non null
if(col == -1)
return false;
return colNulls[col];
}
int ParquetCursor::getInt32(int col) {
return colIntValues[col];
}
long ParquetCursor::getInt64(int col) {
return colIntValues[col];
}
double ParquetCursor::getDouble(int col) {
return colDoubleValues[col];
}
parquet::ByteArray* ParquetCursor::getByteArray(int col) {
return &colByteArrayValues[col];
}
parquet::Type::type ParquetCursor::getPhysicalType(int col) {
return types[col];
}
parquet::LogicalType::type ParquetCursor::getLogicalType(int col) {
return logicalTypes[col];
}
void ParquetCursor::close() {
if(reader != NULL) {
reader->Close();
}
}
void ParquetCursor::reset(std::vector<Constraint> constraints) {
close();
this->constraints = constraints;
rowId = -1;
// TODO: consider having a long lived handle in ParquetTable that can be borrowed
// without incurring the cost of opening the file from scratch twice
reader = parquet::ParquetFileReader::OpenFile(table->file.data());
rowGroupId = -1;
// TODO: handle the case where rowgroups have disjoint schemas?
// TODO: or at least, fail fast if detected
rowsLeftInRowGroup = 0;
numRows = reader->metadata()->num_rows();
numRowGroups = reader->metadata()->num_row_groups();
}
ParquetTable* ParquetCursor::getTable() { return table; }