7. A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed by one or more computer systems, configure the one or more computer systems to perform at least: instructions that cause the one or more computer systems to receive a continuous query to be executed on an event stream, the continuous query being identified based at least in part on an archived relation associated with an application, the archived relation indicating availability of historical data related to the event stream, the historical data stored in a database; instructions that cause the one or more computer systems to generate a physical query plan for the continuous query; instructions that cause the one or more computer systems to determine that an operator identified in the physical query plan is capable of being used to construct a corresponding archiver query based at least in part on a function being performed by the operator and a type of the operator; when it is determined that the operator is capable of being used to construct a corresponding archiver query, instructions that cause the one or more computer systems to determine that the operator is capable of maintaining state information related to the application such that the operator can be used on the event stream after being pre-populated with a state of the operator, the state of the operator providing historical context associated with querying the historical data stored in the database; based at least in part on the instructions that cause the one or more computer systems to determine that the operator is capable of being used to construct the corresponding archiver query and the instructions that cause the one or more computer systems to determine that the operator is capable of maintaining state information, instructions that cause the one or more computer systems to construct the archiver query for the operator; instructions that cause the one or more computer systems to execute the archiver query on the historical data in the database to obtain a result set of data records related to the application; instructions that cause the one or more computer systems to initialize the state of the operator based at least in part on the result set of data records; and instructions that cause the one or more computer systems to execute the continuous query on the event stream in order to generate a snapshot output of one or more data values related to the application based at least in part on pre-populating the operator with the state of the operator.
7. A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed by one or more computer systems, configure the one or more computer systems to perform at least: instructions that cause the one or more computer systems to receive a continuous query to be executed on an event stream, the continuous query being identified based at least in part on an archived relation associated with an application, the archived relation indicating availability of historical data related to the event stream, the historical data stored in a database; instructions that cause the one or more computer systems to generate a physical query plan for the continuous query; instructions that cause the one or more computer systems to determine that an operator identified in the physical query plan is capable of being used to construct a corresponding archiver query based at least in part on a function being performed by the operator and a type of the operator; when it is determined that the operator is capable of being used to construct a corresponding archiver query, instructions that cause the one or more computer systems to determine that the operator is capable of maintaining state information related to the application such that the operator can be used on the event stream after being pre-populated with a state of the operator, the state of the operator providing historical context associated with querying the historical data stored in the database; based at least in part on the instructions that cause the one or more computer systems to determine that the operator is capable of being used to construct the corresponding archiver query and the instructions that cause the one or more computer systems to determine that the operator is capable of maintaining state information, instructions that cause the one or more computer systems to construct the archiver query for the operator; instructions that cause the one or more computer systems to execute the archiver query on the historical data in the database to obtain a result set of data records related to the application; instructions that cause the one or more computer systems to initialize the state of the operator based at least in part on the result set of data records; and instructions that cause the one or more computer systems to execute the continuous query on the event stream in order to generate a snapshot output of one or more data values related to the application based at least in part on pre-populating the operator with the state of the operator. 8. The non-transitory computer-readable storage medium of claim 7 , further comprising: instructions that cause the one or more computer systems to construct a structured query language (SQL) equivalent expression corresponding to an attribute utilized by the operator; instructions that cause the one or more computer systems to construct an output SQL expression for the operator based at least in part on the SQL equivalent expression; and instructions that cause the one or more computer systems to construct the archiver query for the operator based at least in part on the output SQL expression.