This commit introduces code that is intended to replace the current
implicit state machine used by PartitionData. The existing code is still
in use, the new code is NOT used in this commit. A follow-up commit will
switch over to minimise the diff.
This change has two main goals;
* encapsulation & simplification for callers
* robust implementation so developing correct additions is easier
This is a significant refactor of the partition buffering logic to
encapsulate the various states of data (buffering, snapshot, persisting
and the mixed states between them) within the Partition. This alleviates
the rest of the system from having to be concerned with the differences
between "buffering" data, and "unpersisted data", "snapshot data",
"persisting data", "persisting with snapshots" etc - callers now invoke
a method called get_query_data() and they are provided with all the
relevant data for a partition. This abstraction change alone
significantly reduces code and test complexity in the rest of the
ingester.
For the second goal, the new implementation leverages an explicit state
machine, encoded using typestates. Typestate ensures compile-time
correctness of transitions and method calls, and the explicit FSM itself
helps ensure the system progresses in the desired manner - this fixes
and helps prevent bugs caused by implicit states such as:
https://github.com/influxdata/influxdb_iox/issues/5805
This state machine makes the system states explicit and
self-descriptive, helping to reduce the cost of developer on-boarding
(no prior knowledge of "how this bit works") and reduces ongoing
developer burden. This explicit nature also de-risks adding new
functionality - it should be relatively easy to add concurrent snapshot
generation or incremental compaction without introducing bugs. The state
transition logic is abstracted away from callers, minimising the
overhead of this strategy.
Asserts write buffer seeking behaviour, including:
* Seeking past already persisted data correctly
* Skipping to next available op in non-contiguous offset stream
* Skipping to next available op for dropped ops due to retention
* Panics when seeking beyond available data (into the future)
Removes a pair of tests that covered some of the above due to their
tight coupling with ingester internals.
This commit adds a new test that exercises all major external APIs of
the ingester:
* Writing data via the write buffer
* Waiting for data to be readable via the progress API
* Querying data and and asserting the contents
This should provide basic integration coverage for the Ingester
internals. This commit also removes a similar test (though with less
coverage) that was tightly coupled to the existing buffering structures.
Adds a test helper type that maintains the in-memory state for a single
ingester integration test, and provides easy-to-use methods to
manipulate and inspect the ingester instance.
An existing function to map the complex IngesterQueryResponse type to a
simple set of RecordBatch existed in test code - this has been lifted
onto an inherent method on the response type itself for reuse.
* fix: only emit ttbr metric for applied ops
* fix: move DmlApplyAction to s/w accessible
* chore: test for skipped ingest; comments and log improvements
* fix: fixed ingester test re skipping write
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>
* fix: Avoid some allocations by collecting instead of inserting into a vec
* refactor: Encode that adding columns is for one table at a time
* test: Add another test of column limits
* test: Add below/above limit tests for create_or_get_many
* fix: Explicitly DO NOT check column limits when inserting many columns
* feat: Cache the max_columns_per_table on the NamespaceSchema
* feat: Add a function to validate column limits in-memory
* fix: Provide more useful information when over column limits
* fix: Swap types to remove intermediate allocation
* docs: Explain the interactions of the cache and the column limits
* test: Actually set up test that showcases column limit race condition
* fix: Allow writing to existing columns even if table is over column limit
Co-authored-by: Dom <dom@itsallbroken.com>
Copies the existing monotonic partition persistence check into the
partition too - this ensures that even if the partitions are persisted
in order, they are never marked as persisted OUT of order.
Removes the catalog queries previously used to look up various
information about the partition/table/namespace that was already in
memory.
As part of this change, the compaction helper function is changed to
accept the inputs it needs, rather than a struct of data from the
catalog - this significantly simplifies testing.
This commit also adds additional context to all log messages in the
persist() fn.
This commit changes the table ID lookup query from an expensive,
JOIN multi-query to a simple, single table, indexed lookup.
As this is on the hot path, this should help with the recovery rate of
the ingesters.
This commit removes tombstone support from the ingester, and deletes
associated code/helpers/tests. This commit does NOT remove tombstone
support from any other service, but MAY include removing overlapping
test coverage.
This also removes the tombstone support from the Ingester -> Querier RPC
response message.
This has the nice side effect of removing a whole lot of thread spawning
in the ingester tests for the Executor, speeding everything up!
Changes the get() code path to abort the background load task when the
caller will resolve the sort key.
Note that an aborted future will leave the DeferredSortKey without a
background task to fetch the key, and the next caller will have to query
the catalog. Given the rarity of aborted futures, and desire to minimise
catalog load, this seems like a decent trade-off.
This commit also documents the many-readers eager loading problem.
This commit carries the SortKey in the PartitionData, and configures the
ingester to use deferred sort key lookups, smearing the lookups across a
fixed period of time after initialising the PartitionData, instead of
querying for the sort key at persist time.
This allows large numbers of PartitionData to be initialised without
causing a equally large spike in catalog load to resolve the sort key -
instead this load is spread out randomly to reduce peak query rps.
Adds a new DeferredSortKey type that fetches a partition's sort key from
the catalog in the background, or on-demand if not yet pre-fetched.
From the caller's perspective, little has changed compared to reading it
from the catalog directly - the sort key is always returned when calling
get(), regardless of the mechanism, and retries are handled
transparently. Internally the sort key MAY have been pre-fetched in the
background between the DeferredSortKey being initialised, and the call
to get().
The background task waits a (uniformly) random duration of time before
issuing the catalog query to pre-fetch the sort key. This allows large
numbers of DeferredSortKey to (randomly) smear the lookup queries over a
large duration of time. This allows a large number of DeferredSortKey to
be initialised in a short period of time, without creating an equally
large spike in queries against the catalog in the same time period.
- treat OOM protection as "resource exhausted"
- use `DataFusionError` in more places instead of opaque `Box<dyn Error>`
- improve conversion from/into `DataFusionError` to preserve more
semantics
Overall, this improves our error handling. DF can now return errors like
"resource exhausted" and gRPC should now automatically generate a
sensible status code for it.
Fixes#5799.
Changes the ingester's NamespaceData to carry a ref-counted string
identifier as well as the ID.
The backing storage for the name in NamespaceData is shared with the
index map in ShardData, so it is effectively free!
This commit changes the persist() call so that it passes through all
relevant IDs so that the impl can locate the partition in the buffer
tree - this will enable elimination of many queries against the catalog
in the future.
This commit also cleans up the persist() impl, deferring queries until
the result will be used to avoid unnecessary load, improves logging &
error handling, and documents a TOCTOU bug in code:
https://github.com/influxdata/influxdb_iox/issues/5777
Changes the TableData to hold a map of partition key -> PartitionData,
and partition ID -> PartitionData simultaneously. This allows for cheap
lookups when the caller holds an ID.
This commit also manages to internalise the partition map within the
TableData - one less pub / peeking!
This commit also switches from a BTreeMap to a HashMap as the backing
collection, as maintaining key ordering doesn't appear to be necessary.
Changes the ShardData to hold a map of namespace name -> NamespaceData,
and namespace ID -> NamespaceData simultaneously.
This allows for cheap lookups when the caller holds an ID, and is part
of preparatory work to transition away from using string names in the
ingester for tables.
This commit also switches from a BTreeMap to a HashMap as the backing
collection, as maintaining key ordering doesn't appear to be necessary.
Changes the NamespaceData to hold a map of table name -> TableData, and
table ID -> TableData simultaneously.
This allows for cheap lookups when the caller holds an ID, and is part
of preparatory work to transition away from using string names in the
ingester for tables.
This commit also switches from a BTreeMap to a HashMap as the backing
collection, as maintaining key ordering doesn't appear to be necessary.
Fixes a case where the ingester may incorrectly record a write as having
been buffered in memory, when in fact the buffering failed.
This could cause the effective buffer size to be reduced over time as
more and more data is spuriously "added" to the buffer, but never
released back to the memory tracker as it is never persisted.
Changes the NoopLifecycleHandle to MockLifecycleCall, and adds code
causing it to log all calls made to the log_write() method.
This will allow tests to assert calls and their values in DML buffering
tests.
Dom Dwyer
Andrew Lamb
Marco Neumann
dependabot[bot]
Luke Bond
Carol (Nichols || Goulding)
kodiakhq[bot]