15 Commits (3e415aca3d904fa6fa3cbedfdc7a2bdfd7fb6d41)

Author	SHA1	Message	Date
Robert Fratto	f6091a67d1	chore(engine): move to toggleable section prefetching (#19142) ... dataset.readerDownloader was originally introduced in #16429, an attempt to balance peak memory usage of reading a section with read times by downloading a configurable size of pages in advance. In practice, each roundtrip to object storage adds too much of a latency hit, and we've started to set the cache limit high enough to ensure that each reader only needs a single prefetch. Given what we've found, it no longer makes sense to control peak memory usage via the prefetch size. Other options, such as downloading directly to disk, may be explored in the future. In the meantime, this PR removes the ability to specify a cache size. All non-pruned pages will be bulk requested using the range reader (#19067) on the first read call. Pages which have left the potential read window will continue to be eagerly removed for garbage collection. However, we don't want to prefetch when the dataset is entirely in memory, which is the case when the logs section builder is performing k-way merge over in-memory sections. To lower the memory usage of builders, prefetching is configurable. For this initial PR, prefetching is only disabled for the logs section builder; all other reads force prefetching. Signed-off-by: Robert Fratto <robertfratto@gmail.com>	4 months ago
Robert Fratto	595715146f	chore(dataobj)!: introduce new centralized dataset encoding format (#18871) ... Signed-off-by: Robert Fratto <robertfratto@gmail.com>	5 months ago
Ashwanth	5203a0c9ad	chore(dataobj): add reader stats (#18694)	5 months ago
Robert Fratto	9129d8cdd0	chore(engine): use columnar logs.Reader for DataObjScan (#18577)	5 months ago
benclive	1f0edcd4ac	feat: Initial index-builder implementation (#18297)	6 months ago
Robert Fratto	26cb50e65a	chore(dataobj): Improve performance of dataset.Value API (#18339) ... Co-authored-by: Ashwanth <iamashwanth@gmail.com>	6 months ago
benclive	a238816751	perf: Use map for InPredicate when reading dataobj (#18325)	6 months ago
Ashwanth	5c02493fe2	chore(dataobj): avoid reading a predicate column more than once (#18324)	6 months ago
Ashwanth	5961923836	chore(dataobj): apply predicates sequentially (#17283)	8 months ago
Ashwanth	7dd4ab4b09	chore(dataobj): correct stats calculation for prepredicate bytes read (#17279)	9 months ago
benclive	9e68fb01f4	feat(dataobj): Add query stats collection to the dataobj readers (#17128)	9 months ago
Ashwanth	42eed6ded5	chore(dataobj): introduce InPredicate to replace long chain of OR operators (#16919)	9 months ago
Robert Fratto	9be95a3e8c	chore(dataobj): reduce memory overhead of merging logs stripes (#16833)	10 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