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 645 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... | |
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 |
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. | |
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 632 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor ROOT::RNTupleDescriptor::Clone | ( | ) | const |
Definition at line 768 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 743 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 674 of file RNTupleDescriptor.cxx.
ROOT::RResult< void > ROOT::RNTupleDescriptor::DropClusterGroupDetails | ( | ROOT::DescriptorId_t | clusterGroupId | ) |
Definition at line 660 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindClusterId | ( | ROOT::DescriptorId_t | physicalColumnId, |
ROOT::NTupleSize_t | index ) const |
Definition at line 437 of file RNTupleDescriptor.cxx.
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Definition at line 499 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName | ) | const |
Searches for a top-level field.
Definition at line 406 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindFieldId | ( | std::string_view | fieldName, |
ROOT::DescriptorId_t | parentId ) const |
Definition at line 362 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 411 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindNextClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 551 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 426 of file RNTupleDescriptor.cxx.
ROOT::DescriptorId_t ROOT::RNTupleDescriptor::FindPrevClusterId | ( | ROOT::DescriptorId_t | clusterId | ) | const |
Definition at line 562 of file RNTupleDescriptor.cxx.
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Definition at line 777 of file RNTupleDescriptor.hxx.
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Definition at line 773 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RClusterGroupDescriptorIterable ROOT::RNTupleDescriptor::GetClusterGroupIterable | ( | ) | const |
Definition at line 1463 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RClusterDescriptorIterable ROOT::RNTupleDescriptor::GetClusterIterable | ( | ) | const |
Definition at line 1468 of file RNTupleDescriptor.cxx.
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Definition at line 769 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ) | const |
Definition at line 1446 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1452 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RColumnDescriptorIterable ROOT::RNTupleDescriptor::GetColumnIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1458 of file RNTupleDescriptor.cxx.
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Definition at line 806 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RExtraTypeInfoDescriptorIterable ROOT::RNTupleDescriptor::GetExtraTypeInfoIterable | ( | ) | const |
Definition at line 1473 of file RNTupleDescriptor.cxx.
std::vector< std::uint64_t > ROOT::RNTupleDescriptor::GetFeatureFlags | ( | ) | const |
Definition at line 612 of file RNTupleDescriptor.cxx.
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Definition at line 765 of file RNTupleDescriptor.hxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | const RFieldDescriptor & | fieldDesc | ) | const |
Definition at line 1410 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 1415 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetFieldIterable | ( | ROOT::DescriptorId_t | fieldId | ) | const |
Definition at line 1423 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 1428 of file RNTupleDescriptor.cxx.
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Definition at line 822 of file RNTupleDescriptor.hxx.
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Returns the logical parent of all top-level RNTuple data fields.
Definition at line 821 of file RNTupleDescriptor.hxx.
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Definition at line 852 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 845 of file RNTupleDescriptor.hxx.
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Definition at line 813 of file RNTupleDescriptor.hxx.
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Definition at line 805 of file RNTupleDescriptor.hxx.
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Definition at line 811 of file RNTupleDescriptor.hxx.
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Definition at line 812 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 817 of file RNTupleDescriptor.hxx.
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Definition at line 814 of file RNTupleDescriptor.hxx.
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Definition at line 808 of file RNTupleDescriptor.hxx.
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Definition at line 809 of file RNTupleDescriptor.hxx.
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Definition at line 810 of file RNTupleDescriptor.hxx.
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Definition at line 763 of file RNTupleDescriptor.hxx.
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Definition at line 762 of file RNTupleDescriptor.hxx.
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Definition at line 761 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 381 of file RNTupleDescriptor.cxx.
ROOT::RNTupleDescriptor::RFieldDescriptorIterable ROOT::RNTupleDescriptor::GetTopLevelFields | ( | ) | const |
Definition at line 1435 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 1440 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 393 of file RNTupleDescriptor.cxx.
Definition at line 841 of file RNTupleDescriptor.hxx.
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Definition at line 853 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 79 of file RNTupleDescriptorFmt.cxx.
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Definition at line 646 of file RNTupleDescriptor.hxx.
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Potentially a subset of all the available clusters.
Definition at line 699 of file RNTupleDescriptor.hxx.
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Definition at line 693 of file RNTupleDescriptor.hxx.
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Definition at line 664 of file RNTupleDescriptor.hxx.
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Free text from the user.
Definition at line 656 of file RNTupleDescriptor.hxx.
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Definition at line 666 of file RNTupleDescriptor.hxx.
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Definition at line 662 of file RNTupleDescriptor.hxx.
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Definition at line 663 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder.
Definition at line 658 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 691 of file RNTupleDescriptor.hxx.
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Definition at line 667 of file RNTupleDescriptor.hxx.
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The RNTuple name needs to be unique in a given storage location (file)
Definition at line 654 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 682 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when the cluster groups are added.
Definition at line 681 of file RNTupleDescriptor.hxx.
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Updated by the descriptor builder when columns are added.
Definition at line 660 of file RNTupleDescriptor.hxx.
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Like fOnDiskHeaderSize, contains both cluster summaries and page locations.
Definition at line 679 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 677 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 678 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 697 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 672 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 673 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 674 of file RNTupleDescriptor.hxx.
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Set by the descriptor builder when deserialized.
Definition at line 675 of file RNTupleDescriptor.hxx.
Definition at line 710 of file RNTupleDescriptor.hxx.