The RDataSource implementation for RNTuple.
It lets RDataFrame read RNTuple data.
An RDataFrame that reads RNTuple data can be constructed using FromRNTuple().
For each column containing an array or a collection, a corresponding column #colname
is available to access colname.size()
without reading and deserializing the collection values.
Definition at line 46 of file RNTupleDS.hxx.
Public Member Functions | |
RNTupleDS (std::unique_ptr< ROOT::Experimental::Detail::RPageSource > pageSource) | |
~RNTupleDS () | |
void | Finalize () final |
Convenience method called after concluding an event-loop. | |
const std::vector< std::string > & | GetColumnNames () const final |
Returns a reference to the collection of the dataset's column names. | |
std::unique_ptr< ROOT::Detail::RDF::RColumnReaderBase > | GetColumnReaders (unsigned int, std::string_view, const std::type_info &) final |
If the other GetColumnReaders overload returns an empty vector, this overload will be called instead. | |
std::vector< std::pair< ULong64_t, ULong64_t > > | GetEntryRanges () final |
Return ranges of entries to distribute to tasks. | |
std::string | GetLabel () final |
Return a string representation of the datasource type. | |
std::string | GetTypeName (std::string_view colName) const final |
Type of a column as a string, e.g. | |
bool | HasColumn (std::string_view colName) const final |
Checks if the dataset has a certain column. | |
void | Initialize () final |
Convenience method called before starting an event-loop. | |
bool | SetEntry (unsigned int slot, ULong64_t entry) final |
Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot. | |
void | SetNSlots (unsigned int nSlots) final |
Inform RDataSource of the number of processing slots (i.e. | |
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virtual | ~RDataSource ()=default |
virtual void | FinalizeSlot (unsigned int) |
Convenience method called at the end of the data processing associated to a slot. | |
template<typename T > | |
std::vector< T ** > | GetColumnReaders (std::string_view columnName) |
Called at most once per column by RDF. | |
virtual void | InitSlot (unsigned int, ULong64_t) |
Convenience method called at the start of the data processing associated to a slot. | |
Protected Member Functions | |
Record_t | GetColumnReadersImpl (std::string_view name, const std::type_info &) final |
type-erased vector of pointers to pointers to column values - one per slot | |
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virtual std::string | AsString () |
Private Member Functions | |
void | AddField (const RNTupleDescriptor &desc, std::string_view colName, DescriptorId_t fieldId, std::vector< DescriptorId_t > skeinIDs) |
Provides the RDF column "colName" given the field identified by fieldID. | |
Private Attributes | |
std::vector< size_t > | fActiveColumns |
std::vector< std::string > | fColumnNames |
std::vector< std::unique_ptr< ROOT::Experimental::Internal::RNTupleColumnReader > > | fColumnReaderPrototypes |
We prepare a column reader prototype for every column. | |
std::vector< std::string > | fColumnTypes |
bool | fHasSeenAllRanges = false |
unsigned | fNSlots = 0 |
std::vector< std::unique_ptr< ROOT::Experimental::Detail::RPageSource > > | fSources |
Clones of the first source, one for each slot. | |
Additional Inherited Members | |
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using | Record_t = std::vector< void * > |
#include <ROOT/RNTupleDS.hxx>
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explicit |
Definition at line 270 of file RNTupleDS.cxx.
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default |
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private |
Provides the RDF column "colName" given the field identified by fieldID.
For records and collections, AddField recurses into the sub fields. The skeinIDs is the list of field IDs of the outer collections of fieldId. For instance, if fieldId refers to an std::vector<Jet>
, with struct Jet { float pt; float eta; }; AddField will recurse into Jet.pt and Jet.eta and provide the two inner fields as std::vector<float> each.
Definition at line 156 of file RNTupleDS.cxx.
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finalvirtual |
Convenience method called after concluding an event-loop.
See Initialize for more details.
Reimplemented from ROOT::RDF::RDataSource.
Definition at line 340 of file RNTupleDS.cxx.
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inlinefinalvirtual |
Returns a reference to the collection of the dataset's column names.
Implements ROOT::RDF::RDataSource.
Definition at line 78 of file RNTupleDS.hxx.
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finalvirtual |
If the other GetColumnReaders overload returns an empty vector, this overload will be called instead.
[in] | slot | The data processing slot that needs to be considered |
[in] | name | The name of the column for which a column reader needs to be returned |
[in] | tid | A type_info At least one of the two must return a non-empty/non-null value. |
Reimplemented from ROOT::RDF::RDataSource.
Definition at line 286 of file RNTupleDS.cxx.
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finalprotectedvirtual |
type-erased vector of pointers to pointers to column values - one per slot
Implements ROOT::RDF::RDataSource.
Definition at line 279 of file RNTupleDS.cxx.
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finalvirtual |
Return ranges of entries to distribute to tasks.
They are required to be contiguous intervals with no entries skipped. Supposing a dataset with nEntries, the intervals must start at 0 and end at nEntries, e.g. [0-5],[5-10] for 10 entries. This function will be invoked repeatedly by RDataFrame as it needs additional entries to process. The same entry range should not be returned more than once. Returning an empty collection of ranges signals to RDataFrame that the processing can stop.
Implements ROOT::RDF::RDataSource.
Definition at line 301 of file RNTupleDS.cxx.
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inlinefinalvirtual |
Return a string representation of the datasource type.
The returned string will be used by ROOT::RDF::SaveGraph() to represent the datasource in the visualization of the computation graph. Concrete datasources can override the default implementation.
Reimplemented from ROOT::RDF::RDataSource.
Definition at line 82 of file RNTupleDS.hxx.
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finalvirtual |
Type of a column as a string, e.g.
GetTypeName("x") == "double"
. Required for jitting e.g. df.Filter("x>0")
.
[in] | colName | The name of the column |
Implements ROOT::RDF::RDataSource.
Definition at line 324 of file RNTupleDS.cxx.
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finalvirtual |
Checks if the dataset has a certain column.
[in] | colName | The name of the column |
Implements ROOT::RDF::RDataSource.
Definition at line 330 of file RNTupleDS.cxx.
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finalvirtual |
Convenience method called before starting an event-loop.
This method might be called multiple times over the lifetime of a RDataSource, since users can run multiple event-loops with the same RDataFrame. Ideally, Initialize
should set the state of the RDataSource so that multiple identical event-loops will produce identical results.
Reimplemented from ROOT::RDF::RDataSource.
Definition at line 335 of file RNTupleDS.cxx.
Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot.
[in] | slot | The data processing slot that needs to be considered |
[in] | entry | The entry which needs to be pointed to by the reader pointers Slots are adopted to accommodate parallel data processing. Different workers will loop over different ranges and will be labelled by different "slot" values. Returns true if the entry has to be processed, false otherwise. |
Implements ROOT::RDF::RDataSource.
Definition at line 296 of file RNTupleDS.cxx.
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finalvirtual |
Inform RDataSource of the number of processing slots (i.e.
worker threads) used by the associated RDataFrame. Slots numbers are used to simplify parallel execution: RDataFrame guarantees that different threads will always pass different slot values when calling methods concurrently.
Implements ROOT::RDF::RDataSource.
Definition at line 342 of file RNTupleDS.cxx.
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private |
Definition at line 56 of file RNTupleDS.hxx.
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private |
Definition at line 54 of file RNTupleDS.hxx.
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private |
We prepare a column reader prototype for every column.
If a column reader is actually requested in GetColumnReaders(), we move a clone of the prototype into the hands of RDataFrame. Only the clone connects to the backing page store and acquires I/O resources.
Definition at line 53 of file RNTupleDS.hxx.
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private |
Definition at line 55 of file RNTupleDS.hxx.
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private |
Definition at line 59 of file RNTupleDS.hxx.
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private |
Definition at line 58 of file RNTupleDS.hxx.
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private |
Clones of the first source, one for each slot.
Definition at line 48 of file RNTupleDS.hxx.