Level1Snap_change
An internal table that contains snapshots of Level One data to allow a shared memory consumer to quickly get to the current state.
- Section: Snapshot Tables
Metadata
- Base Table Class: Change
- Not in MDB
- Default Size: InstrumentMarket * Constants::MaxLevel1Fields * Constants::DefaultSnapShotSaves = 480000
Fields
| Name | Type | Size (bytes) | Description |
|---|---|---|---|
| Id | Integer (signed) | 8 | The unique identifier of this Level1Snap. |
| Status | Set of Status | 4 | |
| Timestamp | Integer (unsigned) | 8 | The time at which this change record was generated. This is not the same as the business-level timestamp of this Level1Snap_change. |
| InstrumentMarket | Foreign key to InstrumentMarket | 8 | |
| Field | One of LevelOneType | 1 | |
| Value | Integer (signed) | 8 | |
| Group | Integer (unsigned) | 8 | |
| GroupStart | Integer (unsigned) | 8 | |
| TransactionCount | Integer (unsigned) | 8 | |
| ChangeTableIndex | Foreign key to Level1_change | 8 | |
| Sequence | Integer (unsigned) | 8 | |
| NextBCRecord | Integer (unsigned) | 8 | |
| NextChangeRecord | Integer (unsigned) | 8 | The index into the main change table that represents the position of this snapshot. |
| IsLastRecord | Integer (unsigned) | 1 | Set if this record is the end of the snapshot. |
| Active | Integer (unsigned) | 1 | Used internally to determine whether a record has been changed since the last snapshot prior to making a new snapshot - allows records to be squashed. |
| MessagesLeft | Integer (unsigned) | 8 | |
| UpdateNumber | Integer (unsigned) | 8 | A number that records every change that happens to a record. It is primarily used to avoid write after read problems when an intermediate write has changed the originally read record. |
| BCSequence | Integer (unsigned) | 8 | The sequence number of this Level1Snap_change message in the overall broadcast sequence. |
| Reloaded | Integer (unsigned) | 1 | Set to true for change records that are generated during a normal startup from engine cache files. |
| InstanceId | Integer (unsigned) | 4 | |
| RunId | Integer (unsigned) | 4 | |
| ChangedField | One of KVPKey | 4 | |
| CreateUser | Foreign key to User | 8 | The Id of the User that created this Level1Snap. |
| CreateTimestamp | Integer (unsigned) | 8 | The time at which this Level1Snap was created. |
| UpdateUser | Foreign key to User | 8 | The Id of the User that last updated this Level1Snap. |
| UpdateTimestamp | Integer (unsigned) | 8 | The time at which this Level1Snap was last updated. |