| timestamp_ns | UInt64 | 15.74 MiB | 22.28 MiB | 1.41 | 2.95 million | 7.92 | | Timestamp of the sampling moment in nanoseconds. |
| event_time_microseconds | DateTime64(6) | 12.05 MiB | 22.28 MiB | 1.85 | 2.95 million | 7.92 | | Timestamp of the sampling moment with microseconds precision. |
| size | Int64 | 8.66 MiB | 22.28 MiB | 2.57 | 2.95 million | 7.92 | | For trace types Memory, MemorySample or MemoryPeak is the amount of memory allocated, for other trace types is 0. |
| trace | Array(UInt64) | 6.48 MiB | 527.29 MiB | 81.36 | 2.95 million | 187.5 | | Stack trace at the moment of sampling. Each element is a virtual memory address inside ClickHouse server process. |
| query_id | String | 1.70 MiB | 167.21 MiB | 98.49 | 2.95 million | 59.46 | | Query identifier that can be used to get details about a query that was running from the query_log system table. |
| thread_id | UInt64 | 439.64 KiB | 22.28 MiB | 51.89 | 2.95 million | 7.92 | | Thread identifier. |
| event_time | DateTime | 278.38 KiB | 11.14 MiB | 40.97 | 2.95 million | 3.96 | | Timestamp of the sampling moment. |
| trace_type | Enum8('Real' = 0, 'CPU' = 1, 'Memory' = 2, 'MemorySample' = 3, 'MemoryPeak' = 4, 'ProfileEvent' = 5) | 83.10 KiB | 2.78 MiB | 34.31 | 2.95 million | 0.99 | | Trace type: `Real` represents collecting stack traces by wall-clock time. `CPU` represents collecting stack traces by CPU time. `Memory` represents collecting allocations and deallocations when memory allocation exceeds the subsequent watermark. `MemorySample` represents collecting random allocations and deallocations. `MemoryPeak` represents collecting updates of peak memory usage. `ProfileEvent` represents collecting of increments of profile events. |
| revision | UInt32 | 51.13 KiB | 11.14 MiB | 223.09 | 2.95 million | 3.96 | | ClickHouse server build revision. |
| event_date | Date | 25.46 KiB | 5.57 MiB | 224.03 | 2.95 million | 1.98 | | Date of sampling moment. |
| hostname | LowCardinality(String) | 23.64 KiB | 2.83 MiB | 122.73 | 2.95 million | 1.01 | | Hostname of the server executing the query. |
| event | LowCardinality(String) | 23.52 KiB | 2.83 MiB | 123.39 | 2.95 million | 1.01 | | For trace type ProfileEvent is the name of updated profile event, for other trace types is an empty string. |
| increment | Int64 | 6.93 KiB | 28.31 KiB | 4.08 | 2.95 million | 0.01 | | For trace type ProfileEvent is the amount of increment of profile event, for other trace types is 0. |
| ptr | UInt64 | 6.93 KiB | 28.31 KiB | 4.08 | 2.95 million | 0.01 | | The address of the allocated chunk. |
