| timestamp_ns | UInt64 | 13.13 MiB | 35.70 MiB | 2.72 | 4.70 million | 7.97 | | Timestamp of the sampling moment in nanoseconds. |
| trace | Array(UInt64) | 7.34 MiB | 828.85 MiB | 112.89 | 4.70 million | 185 | | Stack trace at the moment of sampling. Each element is a virtual memory address inside ClickHouse server process. |
| event_time_microseconds | DateTime64(6) | 7.10 MiB | 35.70 MiB | 5.03 | 4.70 million | 7.97 | | Timestamp of the sampling moment with microseconds precision. |
| size | Int64 | 6.99 MiB | 35.70 MiB | 5.1 | 4.70 million | 7.97 | | For trace types Memory, MemorySample or MemoryPeak is the amount of memory allocated, for other trace types is 0. |
| query_id | String | 1.99 MiB | 264.90 MiB | 133.35 | 4.70 million | 59.13 | | Query identifier that can be used to get details about a query that was running from the query_log system table. |
| thread_id | UInt64 | 515.97 KiB | 35.70 MiB | 70.84 | 4.70 million | 7.97 | | Thread identifier. |
| event_time | DateTime | 164.43 KiB | 17.85 MiB | 111.14 | 4.70 million | 3.98 | | Timestamp of the sampling moment. |
| trace_type | Enum8('Real' = 0, 'CPU' = 1, 'Memory' = 2, 'MemorySample' = 3, 'MemoryPeak' = 4, 'ProfileEvent' = 5) | 106.92 KiB | 4.46 MiB | 42.73 | 4.70 million | 1 | | 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. |
| event | LowCardinality(String) | 14.14 KiB | 4.50 MiB | 326.3 | 4.70 million | 1.01 | | For trace type ProfileEvent is the name of updated profile event, for other trace types is an empty string. |
| revision | UInt32 | 12.59 KiB | 17.85 MiB | 1451.98 | 4.70 million | 3.98 | | ClickHouse server build revision. |
| hostname | LowCardinality(String) | 12.46 KiB | 4.50 MiB | 370.32 | 4.70 million | 1.01 | | Hostname of the server executing the query. |
| event_date | Date | 6.16 KiB | 8.92 MiB | 1483.16 | 4.70 million | 1.99 | | Date of sampling moment. |
| ptr | UInt64 | 2.37 KiB | 24.79 KiB | 10.47 | 4.70 million | 0.01 | | The address of the allocated chunk. |
| increment | Int64 | 2.37 KiB | 24.79 KiB | 10.47 | 4.70 million | 0.01 | | For trace type ProfileEvent is the amount of increment of profile event, for other trace types is 0. |
