rocksdb/db
Vijay Nadimpalli d150e01474 New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
      const ReadOptions& options, ColumnFamilyHandle* column_family,
      const Slice& key, PinnableSlice* merge_operands,
      GetMergeOperandsOptions* get_merge_operands_options,
      int* number_of_operands)

Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);

Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604

Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist

Differential Revision: D16657366

Pulled By: vjnadimpalli

fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 14:26:44 -07:00
..
compaction Improve CPU Efficiency of ApproximateSize (part 2) (#5609) 2019-07-31 08:50:00 -07:00
db_impl New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
builder.cc Add more callers for table reader. (#5454) 2019-06-20 14:31:48 -07:00
builder.h Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
c_test.c Add C binding for secondary instance (#5505) 2019-06-27 08:58:54 -07:00
c.cc Fix memorty leak in rocksdb_wal_iter_get_batch function (#5515) 2019-07-15 12:59:39 -07:00
column_family_test.cc Make format 2019-05-31 15:24:43 -07:00
column_family.cc Integrate block cache tracer into db_impl (#5433) 2019-06-13 15:43:10 -07:00
column_family.h Integrate block cache tracer into db_impl (#5433) 2019-06-13 15:43:10 -07:00
compact_files_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
compacted_db_impl.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
compacted_db_impl.h Export Import sst files (#5495) 2019-07-17 12:27:14 -07:00
comparator_db_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
convenience.cc Add more callers for table reader. (#5454) 2019-06-20 14:31:48 -07:00
corruption_test.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
cuckoo_table_db_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
db_basic_test.cc Support GetAllKeyVersions() for non-default cf (#5544) 2019-07-07 22:43:52 -07:00
db_blob_index_test.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
db_block_cache_test.cc Move the uncompression dictionary object out of the block cache (#5584) 2019-07-23 16:01:44 -07:00
db_bloom_filter_test.cc Unordered Writes (#5218) 2019-05-13 17:47:21 -07:00
db_compaction_filter_test.cc Apply modernize-use-override (2nd iteration) 2019-02-14 14:41:36 -08:00
db_compaction_test.cc Combine the read-ahead logic for user reads and compaction reads (#5431) 2019-06-19 14:10:46 -07:00
db_dynamic_level_test.cc Fix flaky DBDynamicLevelTest.DynamicLevelMaxBytesBase2 (#4668) 2018-11-12 16:42:16 -08:00
db_encryption_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
db_filesnapshot.cc Add missing check before calling PurgeObsoleteFiles in EnableFileDeletions (#5448) 2019-06-13 14:43:13 -07:00
db_flush_test.cc Ref and unref cfd before and after calling WaitForFlushMemTables (#5513) 2019-07-01 14:12:02 -07:00
db_info_dumper.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
db_info_dumper.h Change RocksDB License 2017-07-15 16:11:23 -07:00
db_inplace_update_test.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
db_io_failure_test.cc Disable DBIOFailureTest.NoSpaceCompactRange in LITE (#4596) 2018-10-29 14:36:31 -07:00
db_iter_stress_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
db_iter_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
db_iter.cc WriteUnPrepared: improve read your own write functionality (#5573) 2019-07-23 08:08:19 -07:00
db_iter.h Make format 2019-05-31 15:24:43 -07:00
db_iterator_test.cc Fix lower bound check error when iterate across file boundary (#5540) 2019-07-04 17:28:30 -07:00
db_log_iter_test.cc Apply modernize-use-override (2nd iteration) 2019-02-14 14:41:36 -08:00
db_memtable_test.cc Fix tsan complaint in ConcurrentMergeWrite test (#5308) 2019-05-15 11:21:48 -07:00
db_merge_operand_test.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
db_merge_operator_test.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
db_options_test.cc fix rocksdb lite and clang contrun test failures (#5477) 2019-06-17 21:16:29 -07:00
db_properties_test.cc Deprecate ttl option from CompactionOptionsFIFO (#4965) 2019-02-15 09:51:41 -08:00
db_range_del_test.cc Fix merging range tombstone covering put during flush/compaction (#5406) 2019-06-04 10:24:14 -07:00
db_sst_test.cc Fix bugs in WAL trash file handling (#5520) 2019-07-06 21:07:32 -07:00
db_statistics_test.cc Make statistics's stats_level change thread-safe (#5030) 2019-03-01 10:42:09 -08:00
db_table_properties_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
db_tailing_iter_test.cc Remove managed iterator 2018-07-17 14:43:18 -07:00
db_test2.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
db_test_util.cc Unordered Writes (#5218) 2019-05-13 17:47:21 -07:00
db_test_util.h simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
db_test.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
db_universal_compaction_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
db_wal_test.cc Fix bugs in DBWALTest.kTolerateCorruptedTailRecords triggered by #5520 (#5550) 2019-07-09 11:18:32 -07:00
db_write_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
dbformat_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
dbformat.cc Avoid user key copying for Get/Put/Write with user-timestamp (#5502) 2019-07-25 15:27:39 -07:00
dbformat.h Avoid user key copying for Get/Put/Write with user-timestamp (#5502) 2019-07-25 15:27:39 -07:00
deletefile_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
error_handler_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
error_handler.cc Make format 2019-05-31 15:24:43 -07:00
error_handler.h Fix typos in comments (#4456) 2018-10-04 20:46:50 -07:00
event_helpers.cc Fix wrong info log printing for num_range_deletions (#5617) 2019-07-23 19:38:16 -07:00
event_helpers.h Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
experimental.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
external_sst_file_basic_test.cc Fix ingested file and direcotry not being sync (#5435) 2019-06-21 10:15:38 -07:00
external_sst_file_ingestion_job.cc Fix ingested file and direcotry not being sync (#5435) 2019-06-21 10:15:38 -07:00
external_sst_file_ingestion_job.h Fix ingested file and direcotry not being sync (#5435) 2019-06-21 10:15:38 -07:00
external_sst_file_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
fault_injection_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
file_indexer_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
file_indexer.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
file_indexer.h Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
filename_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
flush_job_test.cc Integrate block cache tracer into db_impl (#5433) 2019-06-13 15:43:10 -07:00
flush_job.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
flush_job.h Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
flush_scheduler.cc Remove global locks from FlushScheduler (#5372) 2019-06-10 16:50:26 -07:00
flush_scheduler.h Unordered Writes (#5218) 2019-05-13 17:47:21 -07:00
forward_iterator_bench.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
forward_iterator.cc Add more callers for table reader. (#5454) 2019-06-20 14:31:48 -07:00
forward_iterator.h Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
import_column_family_job.cc Export Import sst files (#5495) 2019-07-17 12:27:14 -07:00
import_column_family_job.h Export Import sst files (#5495) 2019-07-17 12:27:14 -07:00
import_column_family_test.cc Fix tsan and valgrind failures in import_column_family_test 2019-07-19 13:25:36 -07:00
internal_stats.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
internal_stats.h Fix MyRocks compile warnings-treated-as-errors on Fedora 30, gcc 9.1.1 (#5553) 2019-07-12 17:30:51 -07:00
job_context.h WritePrepared: Fix visible key compacted out by compaction (#4883) 2019-01-15 21:34:38 -08:00
listener_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
log_format.h Fix an inaccurate comment (#4315) 2018-08-24 18:13:20 -07:00
log_reader.cc Support for single-primary, multi-secondary instances (#4899) 2019-03-26 16:45:31 -07:00
log_reader.h secondary instance: add support for WAL tailing on OpenAsSecondary 2019-04-24 12:08:44 -07:00
log_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
log_writer.cc LogWriter to only flush after finish generating whole record (#5328) 2019-05-21 12:33:17 -07:00
log_writer.h Close WAL files before deletion (#5233) 2019-04-25 10:11:41 -07:00
logs_with_prep_tracker.cc Skip deleted WALs during recovery 2018-05-03 15:43:09 -07:00
logs_with_prep_tracker.h Skip deleted WALs during recovery 2018-05-03 15:43:09 -07:00
lookup_key.h Avoid user key copying for Get/Put/Write with user-timestamp (#5502) 2019-07-25 15:27:39 -07:00
malloc_stats.cc Support jemalloc compiled with --with-jemalloc-prefix (#5521) 2019-07-02 12:07:01 -07:00
malloc_stats.h Change RocksDB License 2017-07-15 16:11:23 -07:00
manual_compaction_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
memtable_list_test.cc Integrate block cache tracer into db_impl (#5433) 2019-06-13 15:43:10 -07:00
memtable_list.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
memtable_list.h New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
memtable.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
memtable.h New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
merge_context.h Introduce a new MultiGet batching implementation (#5011) 2019-04-11 14:28:26 -07:00
merge_helper_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
merge_helper.cc Fix merging range tombstone covering put during flush/compaction (#5406) 2019-06-04 10:24:14 -07:00
merge_helper.h Remove v1 RangeDelAggregator (#4778) 2018-12-17 17:33:46 -08:00
merge_operator.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
merge_test.cc Make format 2019-05-31 15:24:43 -07:00
obsolete_files_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
options_file_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
perf_context_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
pinned_iterators_manager.h Change RocksDB License 2017-07-15 16:11:23 -07:00
plain_table_db_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
pre_release_callback.h WritePrepared: reduce prepared_mutex_ overhead (#5420) 2019-06-10 11:53:31 -07:00
prefix_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
range_del_aggregator_bench.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
range_del_aggregator_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
range_del_aggregator.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
range_del_aggregator.h Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
range_tombstone_fragmenter_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
range_tombstone_fragmenter.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
range_tombstone_fragmenter.h Add compaction logic to RangeDelAggregatorV2 (#4758) 2018-12-17 13:20:51 -08:00
read_callback.h WriteUnPrepared: improve read your own write functionality (#5573) 2019-07-23 08:08:19 -07:00
repair_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
repair.cc Add more callers for table reader. (#5454) 2019-06-20 14:31:48 -07:00
snapshot_checker.h WritePrepared: fix issue with snapshot released during compaction (#4858) 2019-01-16 09:55:32 -08:00
snapshot_impl.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
snapshot_impl.h Refresh snapshot list during long compactions (2nd attempt) (#5278) 2019-05-03 17:30:22 -07:00
table_cache.cc Improve CPU Efficiency of ApproximateSize (part 1) (#5613) 2019-07-23 15:34:33 -07:00
table_cache.h Improve CPU Efficiency of ApproximateSize (part 1) (#5613) 2019-07-23 15:34:33 -07:00
table_properties_collector_test.cc Organizing rocksdb/db directory 2019-05-31 11:57:01 -07:00
table_properties_collector.cc Feature for sampling and reporting compressibility (#4842) 2019-03-18 12:15:34 -07:00
table_properties_collector.h Feature for sampling and reporting compressibility (#4842) 2019-03-18 12:15:34 -07:00
transaction_log_impl.cc Replace Corruption with TryAgain status when new tail is not visible to TransactionLogIterator (#5474) 2019-06-19 08:10:08 -07:00
transaction_log_impl.h Move some file related files outside util/ (#5375) 2019-05-29 20:47:06 -07:00
version_builder_test.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
version_builder.cc simplify include directive involving inttypes (#5402) 2019-06-06 13:56:07 -07:00
version_builder.h Support for single-primary, multi-secondary instances (#4899) 2019-03-26 16:45:31 -07:00
version_edit_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
version_edit.cc Move some logging related files to logging/ (#5387) 2019-05-31 17:23:59 -07:00
version_edit.h Fix MyRocks compile warnings-treated-as-errors on Fedora 30, gcc 9.1.1 (#5553) 2019-07-12 17:30:51 -07:00
version_set_test.cc Integrate block cache tracer into db_impl (#5433) 2019-06-13 15:43:10 -07:00
version_set.cc New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
version_set.h New API to get all merge operands for a Key (#5604) 2019-08-06 14:26:44 -07:00
wal_manager_test.cc Replace Corruption with TryAgain status when new tail is not visible to TransactionLogIterator (#5474) 2019-06-19 08:10:08 -07:00
wal_manager.cc Fix bugs in WAL trash file handling (#5520) 2019-07-06 21:07:32 -07:00
wal_manager.h Fix bugs in WAL trash file handling (#5520) 2019-07-06 21:07:32 -07:00
write_batch_base.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
write_batch_internal.h WriteUnPrepared: savepoint support (#5627) 2019-07-31 13:39:39 -07:00
write_batch_test.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
write_batch.cc WriteUnPrepared: savepoint support (#5627) 2019-07-31 13:39:39 -07:00
write_callback_test.cc WritePrepared: reduce prepared_mutex_ overhead (#5420) 2019-06-10 11:53:31 -07:00
write_callback.h Change RocksDB License 2017-07-15 16:11:23 -07:00
write_controller_test.cc Move test related files under util/ to test_util/ (#5377) 2019-05-30 11:25:51 -07:00
write_controller.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
write_controller.h Change RocksDB License 2017-07-15 16:11:23 -07:00
write_thread.cc Move some memory related files from util/ to memory/ (#5382) 2019-05-30 17:44:09 -07:00
write_thread.h Fix skip WAL for whole write_group when leader's callback fail (#4838) 2019-01-03 12:40:42 -08:00