# Nodetool compactionhistory **compactionhistory** - Provides the history of compaction operations. For example: `nodetool compactionhistory` Example output: ```yaml id shard_id keyspace_name columnfamily_name compaction_name started_at compacted_at bytes_in bytes_out rows_merged sstables_in sstables_out total_tombstone_purge_attempt total_tombstone_purge_failure_due_to_overlapping_with_memtable total_tombstone_purge_failure_due_to_overlapping_with_uncompacting_sstable 17536e70-5358-11e6-9d5f-000000000000 0 ks test Compact 2024-12-17T16:19:55.914 2024-12-17T16:39:55.914 11000 5583 {1: 78, 2: 6} [{generation: 2a5db691-bc8d-11ef-a5f9-bbbda77f5688, origin: memtable, size: 5468}, {generation: 28c58a60-bc8d-11ef-a5f9-bbbda77f5688, origin: memtable, size: 5532}] [{generation: 2a5fb260-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 5583}] 3 0 1 4e164760-5354-11e6-9d5f-000000000000 1 ks test Compact 2024-12-17T16:19:55.913 2024-12-17T16:39:55.913 10919 5490 {1: 56, 2: 2} [{generation: 2a5db691-bc8d-11ef-ad72-bbbca77f5688, origin: memtable, size: 5433}, {generation: 28c58a60-bc8d-11ef-ad72-bbbca77f5688, origin: memtable, size: 5486}] [{generation: 2a5f8b50-bc8d-11ef-ad72-bbbca77f5688, origin: compaction, size: 5490}] 1 0 0 17abc7a0-5358-11e6-9710-000000000001 0 system raft Compact 2024-12-17T16:19:52.570 2024-12-17T16:39:52.570 102199 96181 {1: 20, 2: 3} [{generation: 285b08c0-bc8d-11ef-a5f9-bbbda77f5688, origin: memtable, size: 13683}, {generation: 2798ca30-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 88516}] [{generation: 28614a50-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 96181}] 1 0 0 18537950-5358-11e6-be35-000000000002 0 system_schema columns Compact 2024-12-17T16:19:52.563 2024-12-17T16:39:52.563 25478 19882 {1: 506} [{generation: 28545200-bc8d-11ef-a5f9-bbbda77f5688, origin: memtable, size: 5744}, {generation: 279a02b0-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 19734}] [{generation: 286011d0-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 19882}] 15 0 0 19452c50-5358-11e6-8491-000000000003 0 system topology Compact 2024-12-17T16:19:52.555 2024-12-17T16:39:52.555 22197 14236 {2: 4} [{generation: 00000000-0000-1000-0000-000000000002, origin: memtable, size: 9296}, {generation: 285ba501-bc8d-11ef-a5f9-bbbda77f5688, origin: memtable, size: 12901}] [{generation: 285e3d10-bc8d-11ef-a5f9-bbbda77f5688, origin: compaction, size: 14236}] 0 0 0 ``` Explanation: | Parameter | Description | |----------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------| | id | id of the compaction | | shard_id | id of the shard the compaction was executed on | | keyspace_name | keyspace name that the compaction performed on | | columnfamily_name | columnfamily name that the compaction performed on | | compaction_type | type of compaction, e.g. major, regular, reshard, cleanup, etc. | | started_at | timestamp when the compaction started | | compacted_at | timestamp when the compaction completed | | bytes_in | SSTable size before the compaction | | bytes_out | SSTable size after the compaction | | rows_merged | histogram of merged data (takes into account clustering rows, static rows, range tombstones, etc.) | | sstables_in | list of sstables that were the input of the compaction | | sstables_out | list of sstables that were the output of the compaction (usually one; with ICS/LCS it can be more) | | total_tombstone_purge_attempt | total amount of tombstones that were candidates for garbage-collection | | total_tombstone_purge_failure_due_to_overlapping_with_memtable | purgeable tombstone which couldn’t be collected because memtable contains possibly shadowed data | | total_tombstone_purge_failure_due_to_overlapping_with_uncompacting_sstable | purgeable tombstone which couldn’t be collected because other sstables contains possibly shadowed data | [Nodetool Reference](https://docs.scylladb.com/manual/master/operating-scylla/nodetool.md)