The on-storage meta-data of an ntuple.
Represents the on-disk (on storage) information about an ntuple. The meta-data consists of a header and one or several footers. The header carries the ntuple schema, i.e. the fields and the associated columns and their relationships. The footer(s) carry information about one or several clusters. For every cluster, a footer stores its location and size, and for every column the range of element indexes as well as a list of pages and page locations.
The descriptor provide machine-independent (de-)serialization of headers and footers, and it provides lookup routines for ntuple objects (pages, clusters, ...). It is supposed to be usable by all RPageStorage implementations.
The serialization does not use standard ROOT streamers in order to not let it depend on libCore. The serialization uses the concept of frames: header, footer, and substructures have a preamble with version numbers and the size of the writte struct. This allows for forward and backward compatibility when the meta-data evolves.
Definition at line 628 of file RNTupleDescriptor.hxx.
Classes | |
class | RClusterDescriptorIterable |
Used to loop over all the clusters of an ntuple (in unspecified order) More... | |
class | RClusterGroupDescriptorIterable |
Used to loop over all the cluster groups of an ntuple (in unspecified order) More... | |
class | RColumnDescriptorIterable |
Used to loop over a field's associated columns. More... | |
struct | RCreateModelOptions |
Modifiers passed to CreateModel More... | |
class | RExtraTypeInfoDescriptorIterable |
Used to loop over all the extra type info record of an ntuple (in unspecified order) More... | |
class | RFieldDescriptorIterable |
Used to loop over a field's child fields. More... | |
class | RHeaderExtension |
Summarizes information about fields and the corresponding columns that were added after the header has been serialized. More... | |
Static Public Attributes | |
static constexpr unsigned int | kFeatureFlagTest = 137 |
Private Member Functions | |
RNTupleDescriptor | CloneSchema () const |
Creates a descriptor containing only the schema information about this RNTuple, i.e. | |
ROOT::DescriptorId_t | FindClusterId (ROOT::NTupleSize_t entryIdx) const |
Private Attributes | |
std::unordered_map< ROOT::DescriptorId_t, RClusterDescriptor > | fClusterDescriptors |
May contain only a subset of all the available clusters, e.g. | |
std::unordered_map< ROOT::DescriptorId_t, RClusterGroupDescriptor > | fClusterGroupDescriptors |
std::unordered_map< ROOT::DescriptorId_t, RColumnDescriptor > | fColumnDescriptors |
std::string | fDescription |
Free text from the user. | |
std::vector< RExtraTypeInfoDescriptor > | fExtraTypeInfoDescriptors |
std::set< unsigned int > | fFeatureFlags |
std::unordered_map< ROOT::DescriptorId_t, RFieldDescriptor > | fFieldDescriptors |
ROOT::DescriptorId_t | fFieldZeroId = ROOT::kInvalidDescriptorId |
Set by the descriptor builder. | |
std::uint64_t | fGeneration = 0 |
Once constructed by an RNTupleDescriptorBuilder, the descriptor is mostly immutable except for set of active the page locations. | |
std::unique_ptr< RHeaderExtension > | fHeaderExtension |
std::string | fName |
The ntuple name needs to be unique in a given storage location (file) | |
std::uint64_t | fNClusters = 0 |
Updated by the descriptor builder when the cluster groups are added. | |
std::uint64_t | fNEntries = 0 |
Updated by the descriptor builder when the cluster groups are added. | |
std::uint64_t | fNPhysicalColumns = 0 |
Updated by the descriptor builder when columns are added. | |
std::uint64_t | fOnDiskFooterSize = 0 |
Like fOnDiskHeaderSize, contains both cluster summaries and page locations. | |
std::uint64_t | fOnDiskHeaderSize = 0 |
Set by the descriptor builder when deserialized. | |
std::uint64_t | fOnDiskHeaderXxHash3 = 0 |
Set by the descriptor builder when deserialized. | |
std::vector< ROOT::DescriptorId_t > | fSortedClusterGroupIds |
References cluster groups sorted by entry range and thus allows for binary search. | |
Friends | |
RNTupleDescriptor | Internal::CloneDescriptorSchema (const RNTupleDescriptor &desc) |
class | Internal::RNTupleDescriptorBuilder |
#include <ROOT/RNTupleDescriptor.hxx>
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ROOT::RResult< void > ROOT::RNTupleDescriptor::AddClusterGroupDetails | ( | ROOT::DescriptorId_t | clusterGroupId, |
std::vector< RClusterDescriptor > & | clusterDescs ) |
Methods to load and drop cluster group details (cluster IDs and page locations)
Definition at line 601 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor ROOT::RNTupleDescriptor::Clone | ( | ) | const |
Definition at line 695 of file RNTupleDescriptor.cxx.
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Creates a descriptor containing only the schema information about this RNTuple, i.e.
all the information needed to create a new RNTuple with the same schema as this one but not necessarily the same clustering. This is used when merging two RNTuples.
Definition at line 670 of file RNTupleDescriptor.cxx.
std::unique_ptr< ROOT::Experimental::RNTupleModel > ROOT::RNTupleDescriptor::CreateModel | ( | const RCreateModelOptions & | options = RCreateModelOptions() | ) | const |
Re-create the C++ model from the stored meta-data.
Definition at line 644 of file RNTupleDescriptor.cxx.
ROOT::RResult< void > ROOT::RNTupleDescriptor::DropClusterGroupDetails | ( | ROOT::DescriptorId_t | clusterGroupId | ) |
Definition at line 629 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindClusterId | ( | ROOT::DescriptorId_t | physicalColumnId, |
ROOT::NTupleSize_t | index ) const |
Definition at line 406 of file RNTupleDescriptor.cxx.
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Definition at line 468 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName | ) | const |
Searches for a top-level field.
Definition at line 375 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName, |
ROOT::DescriptorId_t | parentId ) const |
Definition at line 344 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindLogicalColumnId | ( | ROOT::DescriptorId_t | fieldId, |
std::uint32_t | columnIndex, | ||
std::uint16_t | representationIndex ) const |
Definition at line 380 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindNextClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 520 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindPhysicalColumnId | ( | ROOT::DescriptorId_t | fieldId, |
std::uint32_t | columnIndex, | ||
std::uint16_t | representationIndex ) const |
Definition at line 395 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindPrevClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 531 of file RNTupleDescriptor.cxx.
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Definition at line 755 of file RNTupleDescriptor.hxx.
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Definition at line 751 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RClusterGroupDescriptorIterable ROOT::RNTupleDescriptor::GetClusterGroupIterable | ( | ) | const |
Definition at line 1380 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RClusterDescriptorIterable ROOT::RNTupleDescriptor::GetClusterIterable | ( | ) | const |
Definition at line 1385 of file RNTupleDescriptor.cxx.
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Definition at line 747 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ) | const |
Definition at line 1363 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1369 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1375 of file RNTupleDescriptor.cxx.
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Definition at line 784 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RExtraTypeInfoDescriptorIterable ROOT::RNTupleDescriptor::GetExtraTypeInfoIterable | ( | ) | const |
Definition at line 1390 of file RNTupleDescriptor.cxx.
std::vector< std::uint64_t > ROOT::RNTupleDescriptor::GetFeatureFlags | ( | ) | const |
Definition at line 581 of file RNTupleDescriptor.cxx.
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Definition at line 743 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1327 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | const RFieldDescriptor & | fieldDesc, |
const std::function< bool(ROOT::DescriptorId_t, ROOT::DescriptorId_t)> & | comparator ) const |
Definition at line 1332 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1340 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | ROOT::DescriptorId_t | fieldId, |
const std::function< bool(ROOT::DescriptorId_t, ROOT::DescriptorId_t)> & | comparator ) const |
Definition at line 1345 of file RNTupleDescriptor.cxx.
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Definition at line 800 of file RNTupleDescriptor.hxx.
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Returns the logical parent of all top-level NTuple data fields.
Definition at line 799 of file RNTupleDescriptor.hxx.
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Definition at line 827 of file RNTupleDescriptor.hxx.
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Return header extension information; if the descriptor does not have a header extension, return nullptr
Definition at line 820 of file RNTupleDescriptor.hxx.
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Definition at line 791 of file RNTupleDescriptor.hxx.
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Definition at line 783 of file RNTupleDescriptor.hxx.
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Definition at line 789 of file RNTupleDescriptor.hxx.
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Definition at line 790 of file RNTupleDescriptor.hxx.
ROOT::NTupleSize_t ROOT::RNTupleDescriptor::GetNElements | ( | ROOT::DescriptorId_t | physicalColumnId | ) | const |
Definition at line 331 of file RNTupleDescriptor.cxx.
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We know the number of entries from adding the cluster summaries.
Definition at line 795 of file RNTupleDescriptor.hxx.
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Definition at line 792 of file RNTupleDescriptor.hxx.
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Definition at line 786 of file RNTupleDescriptor.hxx.
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Definition at line 787 of file RNTupleDescriptor.hxx.
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Definition at line 788 of file RNTupleDescriptor.hxx.
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Definition at line 741 of file RNTupleDescriptor.hxx.
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Definition at line 740 of file RNTupleDescriptor.hxx.
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Definition at line 739 of file RNTupleDescriptor.hxx.
std::string ROOT::RNTupleDescriptor::GetQualifiedFieldName | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Walks up the parents of the field ID and returns a field name of the form a.b.c.d In case of invalid field ID, an empty string is returned.
Definition at line 363 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetTopLevelFields | ( | ) | const |
Definition at line 1352 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetTopLevelFields | ( | const std::function< bool(ROOT::DescriptorId_t, ROOT::DescriptorId_t)> & | comparator | ) | const |
Definition at line 1357 of file RNTupleDescriptor.cxx.
Definition at line 816 of file RNTupleDescriptor.hxx.
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Definition at line 828 of file RNTupleDescriptor.hxx.
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bool ROOT::RNTupleDescriptor::operator== | ( | const RNTupleDescriptor & | other | ) | const |
Definition at line 316 of file RNTupleDescriptor.cxx.
void ROOT::RNTupleDescriptor::PrintInfo | ( | std::ostream & | output | ) | const |
Definition at line 81 of file RNTupleDescriptorFmt.cxx.
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Definition at line 629 of file RNTupleDescriptor.hxx.
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May contain only a subset of all the available clusters, e.g.
the clusters of the current file from a chain of files
Definition at line 678 of file RNTupleDescriptor.hxx.
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Definition at line 671 of file RNTupleDescriptor.hxx.
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Definition at line 647 of file RNTupleDescriptor.hxx.
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Free text from the user.
Definition at line 639 of file RNTupleDescriptor.hxx.
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Definition at line 649 of file RNTupleDescriptor.hxx.
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Definition at line 645 of file RNTupleDescriptor.hxx.
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Definition at line 646 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder.
Definition at line 641 of file RNTupleDescriptor.hxx.
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Once constructed by an RNTupleDescriptorBuilder, the descriptor is mostly immutable except for set of active the page locations.
During the lifetime of the descriptor, page location information for clusters can be added or removed. When this happens, the generation should be increased, so that users of the descriptor know that the information changed. The generation is increased, e.g., by the page source's exclusive lock guard around the descriptor. It is used, e.g., by the descriptor cache in RNTupleReader.
Definition at line 669 of file RNTupleDescriptor.hxx.
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Definition at line 650 of file RNTupleDescriptor.hxx.
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The ntuple name needs to be unique in a given storage location (file)
Definition at line 637 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 660 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 659 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when columns are added.
Definition at line 643 of file RNTupleDescriptor.hxx.
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Like fOnDiskHeaderSize, contains both cluster summaries and page locations.
Definition at line 657 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 655 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 656 of file RNTupleDescriptor.hxx.
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References cluster groups sorted by entry range and thus allows for binary search.
Note that this list is empty during the descriptor building process and will only be created when the final descriptor is extracted from the builder.
Definition at line 675 of file RNTupleDescriptor.hxx.
Definition at line 689 of file RNTupleDescriptor.hxx.