ApdbCassandra

class lsst.dax.apdb.ApdbCassandra(config: ApdbCassandraConfig)

Bases: Apdb

Implementation of APDB database on to of Apache Cassandra.

The implementation is configured via standard pex_config mechanism using ApdbCassandraConfig configuration class. For an example of different configurations check config/ folder.

Parameters:

configApdbCassandraConfig

Configuration object.

Attributes Summary

metadata	Object controlling access to APDB metadata (ApdbMetadata).
metadataCodeVersionKey	Name of the metadata key to store code version number.
metadataSchemaVersionKey	Name of the metadata key to store schema version number.
partition_zero_epoch	Start time for partition 0, this should never be changed.

Methods Summary

apdbImplementationVersion()	Return version number for current APDB implementation.
apdbSchemaVersion()	Return schema version number as defined in config file.
containsVisitDetector(visit, detector)	Test whether data for a given visit-detector is present in the APDB.
countUnassociatedObjects()	Return the number of DiaObjects that have only one DiaSource associated with them.
dailyJob()	Implement daily activities like cleanup/vacuum.
deleteInsertIds(ids)	Remove insert identifiers from the database.
getDiaForcedSources(region, object_ids, ...)	Return catalog of DiaForcedSource instances from a given region.
getDiaForcedSourcesHistory(ids)	Return catalog of DiaForcedSource instances from a given time period.
getDiaObjects(region)	Return catalog of DiaObject instances from a given region.
getDiaObjectsHistory(ids)	Return catalog of DiaObject instances from a given time period including the history of each DiaObject.
getDiaSources(region, object_ids, visit_time)	Return catalog of DiaSource instances from a given region.
getDiaSourcesHistory(ids)	Return catalog of DiaSource instances from a given time period.
getInsertIds()	Return collection of insert identifiers known to the database.
getSSObjects()	Return catalog of SSObject instances.
makeField(doc)	Make a ConfigurableField for Apdb.
makeSchema([drop])	Create or re-create whole database schema.
reassignDiaSources(idMap)	Associate DiaSources with SSObjects, dis-associating them from DiaObjects.
store(visit_time, objects[, sources, ...])	Store all three types of catalogs in the database.
storeSSObjects(objects)	Store or update SSObject catalog.
tableDef(table)	Return table schema definition for a given table.

Attributes Documentation

metadata

metadataCodeVersionKey = 'version:ApdbCassandra'

Name of the metadata key to store code version number.

metadataSchemaVersionKey = 'version:schema'

Name of the metadata key to store schema version number.

partition_zero_epoch = DateTime("1970-01-01T00:00:00.000000000", TAI)

Start time for partition 0, this should never be changed.

Methods Documentation

classmethod apdbImplementationVersion() → VersionTuple

Return version number for current APDB implementation.

Returns:

versionVersionTuple

Version of the code defined in implementation class.

apdbSchemaVersion() → VersionTuple

Return schema version number as defined in config file.

Returns:

versionVersionTuple

Version of the schema defined in schema config file.

containsVisitDetector(visit: int, detector: int) → bool

Test whether data for a given visit-detector is present in the APDB.

Parameters:

visit, detectorint

The ID of the visit-detector to search for.

Returns:

presentbool

True if some DiaObject, DiaSource, or DiaForcedSource records exist for the specified observation, False otherwise.

countUnassociatedObjects() → int

Return the number of DiaObjects that have only one DiaSource associated with them.

Used as part of ap_verify metrics.

Returns:

countint

Number of DiaObjects with exactly one associated DiaSource.

Notes

This method can be very inefficient or slow in some implementations.

dailyJob() → None

Implement daily activities like cleanup/vacuum.

What should be done during daily activities is determined by specific implementation.

deleteInsertIds(ids: Iterable[ApdbInsertId]) → None

Remove insert identifiers from the database.

Parameters:

idsiterable [ApdbInsertId]

Insert identifiers, can include items returned from getInsertIds.

Notes

This method causes Apdb to forget about specified identifiers. If there are any auxiliary data associated with the identifiers, it is also removed from database (but data in regular tables is not removed). This method should be called after successful transfer of data from APDB to PPDB to free space used by history.

getDiaForcedSources(region: Region, object_ids: Iterable[int] | None, visit_time: DateTime) → DataFrame | None

Return catalog of DiaForcedSource instances from a given region.

Parameters:

regionlsst.sphgeom.Region

Region to search for DIASources.

object_idsiterable [ int ], optional

List of DiaObject IDs to further constrain the set of returned sources. If list is empty then empty catalog is returned with a correct schema. If None then returned sources are not constrained. Some implementations may not support latter case.

visit_timelsst.daf.base.DateTime

Time of the current visit.

Returns:

catalogpandas.DataFrame, or None

Catalog containing DiaSource records. None is returned if read_forced_sources_months configuration parameter is set to 0.

Raises:

NotImplementedError

May be raised by some implementations if object_ids is None.

Notes

This method returns DiaForcedSource catalog for a region with additional filtering based on DiaObject IDs. Only a subset of DiaSource history is returned limited by read_forced_sources_months config parameter, w.r.t. visit_time. If object_ids is empty then an empty catalog is always returned with the correct schema (columns/types). If object_ids is None then no filtering is performed and some of the returned records may be outside the specified region.

getDiaForcedSourcesHistory(ids: Iterable[ApdbInsertId]) → ApdbTableData

Return catalog of DiaForcedSource instances from a given time period.

Parameters:

idsiterable [ApdbInsertId]

Insert identifiers, can include items returned from getInsertIds.

Returns:

dataApdbTableData

Catalog containing DiaForcedSource records. In addition to all regular columns it will contain insert_id column.

Notes

This part of API may not be very stable and can change before the implementation finalizes.

getDiaObjects(region: Region) → DataFrame

Return catalog of DiaObject instances from a given region.

This method returns only the last version of each DiaObject. Some records in a returned catalog may be outside the specified region, it is up to a client to ignore those records or cleanup the catalog before futher use.

Parameters:

regionlsst.sphgeom.Region

Region to search for DIAObjects.

Returns:

catalogpandas.DataFrame

Catalog containing DiaObject records for a region that may be a superset of the specified region.

getDiaObjectsHistory(ids: Iterable[ApdbInsertId]) → ApdbTableData

Return catalog of DiaObject instances from a given time period including the history of each DiaObject.

Parameters:

idsiterable [ApdbInsertId]

Insert identifiers, can include items returned from getInsertIds.

Returns:

dataApdbTableData

Catalog containing DiaObject records. In addition to all regular columns it will contain insert_id column.

Notes

This part of API may not be very stable and can change before the implementation finalizes.

getDiaSources(region: Region, object_ids: Iterable[int] | None, visit_time: DateTime) → DataFrame | None

Return catalog of DiaSource instances from a given region.

Parameters:

regionlsst.sphgeom.Region

Region to search for DIASources.

object_idsiterable [ int ], optional

List of DiaObject IDs to further constrain the set of returned sources. If None then returned sources are not constrained. If list is empty then empty catalog is returned with a correct schema.

visit_timelsst.daf.base.DateTime

Time of the current visit.

Returns:

catalogpandas.DataFrame, or None

Catalog containing DiaSource records. None is returned if read_sources_months configuration parameter is set to 0.

Notes

This method returns DiaSource catalog for a region with additional filtering based on DiaObject IDs. Only a subset of DiaSource history is returned limited by read_sources_months config parameter, w.r.t. visit_time. If object_ids is empty then an empty catalog is always returned with the correct schema (columns/types). If object_ids is None then no filtering is performed and some of the returned records may be outside the specified region.

getDiaSourcesHistory(ids: Iterable[ApdbInsertId]) → ApdbTableData

Return catalog of DiaSource instances from a given time period.

Parameters:

idsiterable [ApdbInsertId]

Insert identifiers, can include items returned from getInsertIds.

Returns:

dataApdbTableData

Catalog containing DiaSource records. In addition to all regular columns it will contain insert_id column.

Notes

This part of API may not be very stable and can change before the implementation finalizes.

getInsertIds() → list[lsst.dax.apdb.apdb.ApdbInsertId] | None

Return collection of insert identifiers known to the database.

Returns:

idslist [ApdbInsertId] or None

List of identifiers, they may be time-ordered if database supports ordering. None is returned if database is not configured to store insert identifiers.

getSSObjects() → DataFrame

Return catalog of SSObject instances.

Returns:

catalogpandas.DataFrame

Catalog containing SSObject records, all existing records are returned.

classmethod makeField(doc: str) → ConfigurableField

Make a ConfigurableField for Apdb.

Parameters:

docstr

Help text for the field.

Returns:

configurableFieldlsst.pex.config.ConfigurableField

A ConfigurableField for Apdb.

makeSchema(drop: bool = False) → None

Create or re-create whole database schema.

Parameters:

dropbool

If True then drop all tables before creating new ones.

reassignDiaSources(idMap: Mapping[int, int]) → None

Associate DiaSources with SSObjects, dis-associating them from DiaObjects.

Parameters:

idMapMapping

Maps DiaSource IDs to their new SSObject IDs.

Raises:

ValueError

Raised if DiaSource ID does not exist in the database.

store(visit_time: DateTime, objects: DataFrame, sources: DataFrame | None = None, forced_sources: DataFrame | None = None) → None

Store all three types of catalogs in the database.

Parameters:

visit_timelsst.daf.base.DateTime

Time of the visit.

objectspandas.DataFrame

Catalog with DiaObject records.

sourcespandas.DataFrame, optional

Catalog with DiaSource records.

forced_sourcespandas.DataFrame, optional

Catalog with DiaForcedSource records.

Notes

This methods takes DataFrame catalogs, their schema must be compatible with the schema of APDB table:

• column names must correspond to database table columns

• types and units of the columns must match database definitions, no unit conversion is performed presently

• columns that have default values in database schema can be omitted from catalog

• this method knows how to fill interval-related columns of DiaObject (validityStart, validityEnd) they do not need to appear in a catalog

• source catalogs have diaObjectId column associating sources with objects

storeSSObjects(objects: DataFrame) → None

Store or update SSObject catalog.

Parameters:

objectspandas.DataFrame

Catalog with SSObject records.

Notes

If SSObjects with matching IDs already exist in the database, their records will be updated with the information from provided records.

tableDef(table: ApdbTables) → Table | None

Return table schema definition for a given table.

Parameters:

tableApdbTables

One of the known APDB tables.

Returns:

tableSchemafelis.simple.Table or None

Table schema description, None is returned if table is not defined by this implementation.