3 Commits (3e415aca3d904fa6fa3cbedfdc7a2bdfd7fb6d41)

Author	SHA1	Message	Date
Ashwanth	88c8b44f2d	chore(dataobj): read non-projected predicate columns (#18797)	5 months ago
Robert Fratto	9129d8cdd0	chore(engine): use columnar logs.Reader for DataObjScan (#18577)	5 months ago
Robert Fratto	06cf52757b	chore(dataobj): Add columnar reading APIs to logs and streams sections (#17976) ... This PR introduces columnar reading APIs to both the logs and streams sections. As part of this change, both sections now expose the columns stored in the section, which are then used to define predicates on the readers. The columnar reading APIs emit a sequence of `arrow.Record`s, where each record has no more than the batch size passed to the `Reader.Read` method. Unlike the original row-based readers, the columnar readers: * Allow reading a subset of columns * Have column-based predicates that map literally to the new query engine To be able to represent a column's value for use in predicates, we import [github.com/apache/arrow-go/v18/arrow/scalar](https://pkg.go.dev/github.com/apache/arrow-go/v18@v18.3.0/arrow/scalar). Section Reader implementations perform mapping to and from the internal `dataset.Value`. The implementation of `logs.Reader` is almost an identical copy of the `streams.Reader` implementation. I've opted for duplicating the implementation in the short term, since there's no obvious way for how to deduplicate it in a way keeps the package structure easy to understand. We can change this in the future if a clean and simple approach presents itself. This PR does not yet update `DataObjScan` to make use of these new APIs; that's being left out of scope for another PR to handle.	7 months ago
Ashwanth	42eed6ded5	chore(dataobj): introduce InPredicate to replace long chain of OR operators (#16919)	9 months ago
Robert Fratto	cd11367148	chore(dataobj): Wire dataset.Reader into dataobj.LogsReader and dataobj.StreamsReader (#16701) ... Co-authored-by: Ashwanth Goli <iamashwanth@gmail.com>	10 months ago
Robert Fratto	7f0dc01e21	chore(dataobj): introduce more efficient dataset reading (#16429) ... This commit introduces a new API, dataset.Reader, which scans through values in datasets more efficiently than dataset.Iter. As a result, dataset.Iter has been removed in favour of the new Reader. dataset.Reader is more efficient than dataset.Iter because: - It avoids using iter.Pull; the number of values flowing through coroutines added a significant amount of CPU overhead. - It supports efficient uses of predicates, where non-predicate columns are only loaded after finding matching rows from predicate columns; this avoids loading unnecessary pages. - It adds initial support for bulk page downloading, so that we need fewer roundtrips to object storage when iterating over a dataset. (This is not fully implemented yet; see below). - Early performance benchmarks see a ~3.4x speed improvement over reading 7GB of uncompressed logs, going from 192 MB/s (with dataset.Iter) to 652 MB/s (with dataset.Reader). This commit is truly massive, and to avoid it getting any larger, I'm leaving some follow up work to additional commits: - Updating dataobj.LogsReader and dataobj.StreamsReader to use the new API. - Adding support for downloading pages in batches; dataset.Reader will request multiple pages at once, but our decoder still unwraps that into several GET requests to object storage. Signed-off-by: Robert Fratto <robertfratto@gmail.com> Co-authored-by: Cyril Tovena <cyril.tovena@gmail.com>	10 months ago