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db_indexes.md

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Recommended database indexes

STH uses one database per service (name pattern: sth_<service>) with two collections:

  • Raw data collection (name pattern: sth_/<subserviceName>)
  • Aggregated data collection (name pattern: sth_/<subserviceName>.aggr)

Indexes in the raw data collection

It is recommended to create the following index in this collection:

{entityId: 1, entityType: 1, attrName: 1, recvTime: 1}

The performance difference can be dramatic for large sets of data. For instance, for a collection with around ~3000000 query execution time can drop from 3 seconds to 1 millisecond.

Since version 3.0.0 of cygnus an index named cyg_raw_opt is created in this way but depending on datamodel:

datamodel keys
dm-by-servicepath recvTime, entityId, entityType, attrName, attrType, attrValue
dm-by-entity recvTime, attrName, attrType, attrValue
dm-by-attribute recvTime, attrType, attrValue

Note that datamodel others that the ones above are not allowed by Cygnus.

Indexes in the aggregated data collection

It is recommended to create the following index in this collection:

{ "_id.entityId": 1, "_id.entityType": 1, "_id.attrName": 1, "_id.resolution": 1, "_id.origin": 1 }

The performance difference can be dramatic for large sets of data. For instance, for a collection with around ~6000000 query execution time can drop from 28 seconds to 20 millisecond.

Since version 3.0.0 of cygnus index named cyg_agg_opt is created in this way but depending on datamodel:

datamodel keys
dm-by-servicepath entityId, entityType, attrName, resolution, origin
dm-by-entity attrName, resolution, origin
dm-by-attribute resolution, origin

Note that datamodel others that the ones above are not allowed by Cygnus.