The on-storage metadata of an RNTuple.
Represents the on-disk (on storage) information about an RNTuple. The metadata consists of a header, a footer, and potentially multiple page lists. The header carries the RNTuple schema, i.e. the fields and the associated columns and their relationships. The footer carries information about one or several cluster groups and links to their page lists. For every cluster group, a page list envelope stores cluster summaries and page locations. For every cluster, it stores for every column the range of element indexes as well as a list of pages and page locations.
The descriptor provides machine-independent (de-)serialization of headers and footers, and it provides lookup routines for RNTuple 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 envelopes and frames: header, footer, and page list envelopes have a preamble with a type ID and length. Substructures are serialized in frames and have a size and number of items (for list frames). This allows for forward and backward compatibility when the metadata evolves.
Definition at line 704 of file RNTupleDescriptor.hxx.
Classes | |
| class | RClusterDescriptorIterable |
| Used to loop over all the clusters of an RNTuple (in unspecified order) More... | |
| class | RClusterGroupDescriptorIterable |
| Used to loop over all the cluster groups of an RNTuple (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 RNTuple (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... | |
Public Types | |
| enum | EFeatureFlags { kFeatureFlag_NestedDeferredColumns = 0 , kFeatureFlag_COUNT , kFeatureFlag_Test = 137 } |
| All known feature flags. More... | |
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::vector< Experimental::RNTupleAttrSetDescriptor > | fAttributeSets |
| List of AttributeSets linked to this RNTuple. | |
| std::unordered_map< ROOT::DescriptorId_t, RClusterDescriptor > | fClusterDescriptors |
| Potentially a subset of all the available clusters. | |
| 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 |
| The generation of the descriptor. | |
| std::unique_ptr< RHeaderExtension > | fHeaderExtension |
| std::string | fName |
| The RNTuple 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. | |
| std::uint16_t | fVersionEpoch = 0 |
| Set by the descriptor builder when deserialized. | |
| std::uint16_t | fVersionMajor = 0 |
| Set by the descriptor builder when deserialized. | |
| std::uint16_t | fVersionMinor = 0 |
| Set by the descriptor builder when deserialized. | |
| std::uint16_t | fVersionPatch = 0 |
| Set by the descriptor builder when deserialized. | |
#include <ROOT/RNTupleDescriptor.hxx>
All known feature flags.
Note that the flag values represent the bit index, not the already-bitshifted integer.
| Enumerator | |
|---|---|
| kFeatureFlag_NestedDeferredColumns | Signals that the RNTuple contains at least one deferred column that is part of a collection and was extended (i.e. it appears in the footer). This can happen when merging two RNTuples that have the same collection field backed by columns with different encoding, e.g. a vector<float> whose elements are represented by SplitReal32 in the first ntuple and by Real32 in the second. Added in version 1.1.0.0 of the binary format. |
| kFeatureFlag_COUNT | |
| kFeatureFlag_Test | Reserved for forward-compatibility testing. |
Definition at line 774 of file 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 660 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor ROOT::RNTupleDescriptor::Clone | ( | ) | const |
Definition at line 796 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 771 of file RNTupleDescriptor.cxx.
| std::unique_ptr< ROOT::RNTupleModel > ROOT::RNTupleDescriptor::CreateModel | ( | const RCreateModelOptions & | options = RCreateModelOptions() | ) | const |
Re-create the C++ model from the stored metadata.
Definition at line 702 of file RNTupleDescriptor.cxx.
| ROOT::RResult< void > ROOT::RNTupleDescriptor::DropClusterGroupDetails | ( | ROOT::DescriptorId_t | clusterGroupId | ) |
Definition at line 688 of file RNTupleDescriptor.cxx.
| ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindClusterId | ( | ROOT::DescriptorId_t | physicalColumnId, |
| ROOT::NTupleSize_t | index ) const |
Definition at line 467 of file RNTupleDescriptor.cxx.
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Definition at line 529 of file RNTupleDescriptor.cxx.
| ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName | ) | const |
Searches for a top-level field.
Definition at line 436 of file RNTupleDescriptor.cxx.
| ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName, |
| ROOT::DescriptorId_t | parentId ) const |
Definition at line 392 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 441 of file RNTupleDescriptor.cxx.
| ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindNextClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 581 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 456 of file RNTupleDescriptor.cxx.
| ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindPrevClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 592 of file RNTupleDescriptor.cxx.
| ROOT::Experimental::RNTupleAttrSetDescriptorIterable ROOT::RNTupleDescriptor::GetAttrSetIterable | ( | ) | const |
Definition at line 1524 of file RNTupleDescriptor.cxx.
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Definition at line 863 of file RNTupleDescriptor.hxx.
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Definition at line 859 of file RNTupleDescriptor.hxx.
| ROOT::RNTupleDescriptor::RClusterGroupDescriptorIterable ROOT::RNTupleDescriptor::GetClusterGroupIterable | ( | ) | const |
Definition at line 1509 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor::RClusterDescriptorIterable ROOT::RNTupleDescriptor::GetClusterIterable | ( | ) | const |
Definition at line 1514 of file RNTupleDescriptor.cxx.
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Definition at line 855 of file RNTupleDescriptor.hxx.
| ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ) | const |
Definition at line 1492 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1498 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1504 of file RNTupleDescriptor.cxx.
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Definition at line 894 of file RNTupleDescriptor.hxx.
| ROOT::RNTupleDescriptor::RExtraTypeInfoDescriptorIterable ROOT::RNTupleDescriptor::GetExtraTypeInfoIterable | ( | ) | const |
Definition at line 1519 of file RNTupleDescriptor.cxx.
| std::vector< std::uint64_t > ROOT::RNTupleDescriptor::GetFeatureFlags | ( | ) | const |
Definition at line 640 of file RNTupleDescriptor.cxx.
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Definition at line 851 of file RNTupleDescriptor.hxx.
| ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1456 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 1461 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1469 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 1474 of file RNTupleDescriptor.cxx.
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Definition at line 911 of file RNTupleDescriptor.hxx.
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Returns the logical parent of all top-level RNTuple data fields.
Definition at line 910 of file RNTupleDescriptor.hxx.
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Definition at line 941 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 934 of file RNTupleDescriptor.hxx.
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Definition at line 901 of file RNTupleDescriptor.hxx.
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Definition at line 893 of file RNTupleDescriptor.hxx.
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Definition at line 903 of file RNTupleDescriptor.hxx.
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Definition at line 899 of file RNTupleDescriptor.hxx.
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Definition at line 900 of file RNTupleDescriptor.hxx.
| ROOT::NTupleSize_t ROOT::RNTupleDescriptor::GetNElements | ( | ROOT::DescriptorId_t | physicalColumnId | ) | const |
Definition at line 361 of file RNTupleDescriptor.cxx.
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We know the number of entries from adding the cluster summaries.
Definition at line 906 of file RNTupleDescriptor.hxx.
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Definition at line 902 of file RNTupleDescriptor.hxx.
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Definition at line 896 of file RNTupleDescriptor.hxx.
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Definition at line 897 of file RNTupleDescriptor.hxx.
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Definition at line 898 of file RNTupleDescriptor.hxx.
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Definition at line 843 of file RNTupleDescriptor.hxx.
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Definition at line 842 of file RNTupleDescriptor.hxx.
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Definition at line 841 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 411 of file RNTupleDescriptor.cxx.
| ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetTopLevelFields | ( | ) | const |
Definition at line 1481 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 1486 of file RNTupleDescriptor.cxx.
| std::string ROOT::RNTupleDescriptor::GetTypeNameForComparison | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Adjust the type name of the passed RFieldDescriptor for comparison with another renormalized type name.
Definition at line 423 of file RNTupleDescriptor.cxx.
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Definition at line 845 of file RNTupleDescriptor.hxx.
Definition at line 930 of file RNTupleDescriptor.hxx.
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Definition at line 942 of file RNTupleDescriptor.hxx.
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| bool ROOT::RNTupleDescriptor::operator== | ( | const RNTupleDescriptor & | other | ) | const |
Definition at line 346 of file RNTupleDescriptor.cxx.
| void ROOT::RNTupleDescriptor::PrintInfo | ( | std::ostream & | output | ) | const |
Definition at line 79 of file RNTupleDescriptorFmt.cxx.
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Definition at line 796 of file RNTupleDescriptor.hxx.
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Definition at line 705 of file RNTupleDescriptor.hxx.
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List of AttributeSets linked to this RNTuple.
Definition at line 761 of file RNTupleDescriptor.hxx.
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Potentially a subset of all the available clusters.
Definition at line 759 of file RNTupleDescriptor.hxx.
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Definition at line 753 of file RNTupleDescriptor.hxx.
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Definition at line 724 of file RNTupleDescriptor.hxx.
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Free text from the user.
Definition at line 716 of file RNTupleDescriptor.hxx.
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Definition at line 726 of file RNTupleDescriptor.hxx.
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Definition at line 722 of file RNTupleDescriptor.hxx.
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Definition at line 723 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder.
Definition at line 718 of file RNTupleDescriptor.hxx.
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The generation of the descriptor.
Once constructed by an RNTupleDescriptorBuilder, the descriptor is mostly immutable except for the set of active 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 751 of file RNTupleDescriptor.hxx.
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Definition at line 727 of file RNTupleDescriptor.hxx.
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The RNTuple name needs to be unique in a given storage location (file)
Definition at line 714 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 742 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 741 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when columns are added.
Definition at line 720 of file RNTupleDescriptor.hxx.
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Like fOnDiskHeaderSize, contains both cluster summaries and page locations.
Definition at line 739 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 737 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 738 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 757 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 732 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 733 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 734 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 735 of file RNTupleDescriptor.hxx.