# Index types

In order to support the described retrieval use cases, LID maintains the following indexes:

#### multihash → \[]piece cid

To look up which pieces contain a block

#### piece cid → sector information {sector ID, offset, size}

To look up which sector a piece is in

#### piece cid → map\<mulithash → block offset / size>

To look up where in the piece a block is and the block’s size

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