Currently, newly created segment could be chosen to be compaction
candidate, which is prone to bugs and segment file open failures. We
should skip last (maybe active) segment while doing segcompaction.
1.remove quick_compaction's rowset pick policy, call cu compaction when trigger
quick compaction
2. skip tablet's compaction task when compaction score is too small
Co-authored-by: yixiutt <yixiu@selectdb.com>
mem tracker can be logically divided into 4 layers: 1)process 2)type 3)query/load/compation task etc. 4)exec node etc.
type includes
enum Type {
GLOBAL = 0, // Life cycle is the same as the process, e.g. Cache and default Orphan
QUERY = 1, // Count the memory consumption of all Query tasks.
LOAD = 2, // Count the memory consumption of all Load tasks.
COMPACTION = 3, // Count the memory consumption of all Base and Cumulative tasks.
SCHEMA_CHANGE = 4, // Count the memory consumption of all SchemaChange tasks.
CLONE = 5, // Count the memory consumption of all EngineCloneTask. Note: Memory that does not contain make/release snapshots.
BATCHLOAD = 6, // Count the memory consumption of all EngineBatchLoadTask.
CONSISTENCY = 7 // Count the memory consumption of all EngineChecksumTask.
}
Object pointers are no longer saved between each layer, and the values of process and each type are periodically aggregated.
other fix:
In [fix](memtracker) Fix transmit_tracker null pointer because phamp is not thread safe #13528, I tried to separate the memory that was manually abandoned in the query from the orphan mem tracker. But in the actual test, the accuracy of this part of the memory cannot be guaranteed, so put it back to the orphan mem tracker again.
## Design
### Trigger
Every time when a rowset writer produces more than N (e.g. 10) segments, we trigger segment compaction. Note that only one segment compaction job for a single rowset at a time to ensure no recursing/queuing nightmare.
### Target Selection
We collect segments during every trigger. We skip big segments whose row num > M (e.g. 10000) coz we get little benefits from compacting them comparing our effort. Hence, we only pick the 'Longest Consecutive Small" segment group to do actual compaction.
### Compaction Process
A new thread pool is introduced to help do the job. We submit the above-mentioned 'Longest Consecutive Small" segment group to the pool. Then the worker thread does the followings:
- build a MergeIterator from the target segments
- create a new segment writer
- for each block readed from MergeIterator, the Writer append it
### SegID handling
SegID must remain consecutive after segment compaction.
If a rowset has small segments named seg_0, seg_1, seg_2, seg_3 and a big segment seg_4:
- we create a segment named "seg_0-3" to save compacted data for seg_0, seg_1, seg_2 and seg_3
- delete seg_0, seg_1, seg_2 and seg_3
- rename seg_0-3 to seg_0
- rename seg_4 to seg_1
It is worth noticing that we should wait inflight segment compaction tasks to finish before building rowset meta and committing this txn.
1.remove quick_compaction's rowset pick policy, call cu compaction when trigger
quick compaction
2. skip tablet's compaction task when compaction score is too small
Co-authored-by: yixiutt <yixiu@selectdb.com>
Fix _delete_sign_idx and _seq_col_idx when append_column or build_schema when load.
Tablet schema cache support recycle when schema sptr use count equals 1.
Add a http interface for flink-connector to sync ddl.
Improve tablet->tablet_schema() by max_version_schema.
Refactor TaggableLogger
Refactor status handling in agent task:
Unify log format in TaskWorkerPool
Pass Status to the top caller, and replace some OLAPInternalError with more detailed error message Status
Premature return with the opposite condition to reduce indention
1. use rlock in most logic instead of wrlock
2. filter stale rowset's delete bitmap in save meta
3. add a delete_bitmap lock to handle compaction and publish_txn confict
Co-authored-by: yixiutt <yixiu@selectdb.com>
some feature:
1. add min max key in segment footer to speed up get_row_ranges_by_keys
2. do not load pk bloom filter in query
Co-authored-by: yixiutt <yixiu@selectdb.com>
In our origin design, we calc delete bitmap in publish txn, and this operation
will cost too much time as it will load segment data and lookup row key in pre
rowset and segments.And publish version task should run in order, so it'll lead
to timeout in publish_txn.
In this pr, we seperate delete_bitmap calculation to tow part, one of it will be
done in flush mem table, so this work can run parallel. And we calc final
delete_bitmap in publish_txn, get a rowset_id set that should be included and
remove rowsets that has been compacted, the rowset difference between memtable_flush
and publish_txn is really small so publish_txn become very fast.In our test,
publish_txn cost about 10ms.
Co-authored-by: yixiutt <yixiu@selectdb.com>
* not need call delete handler to filter rows since they are filtered in rowset reader
* need not call delete eval in schema change and remove related code
Co-authored-by: yiguolei <yiguolei@gmail.com>
During load process, the same operation are performed on all replicas such as sort and aggregation,
which are resource-intensive.
Concurrent data load would consume much CPU and memory resources.
It's better to perform write process (writing data into MemTable and then data flush) on single replica
and synchronize data files to other replicas before transaction finished.
1.make version publish work in version order
2.update delete bitmap while publish version, load current version rowset
primary key and search in pre rowsets
3.speed up publish version task by parallel tablet publish task
Co-authored-by: yixiutt <yixiu@selectdb.com>
