TOPK.RESERVE

Initializes a Top-K sketch with specified parameters.

Parameters

• key: the name of the Top-k sketch.
• topk: the number of top (k) occurring items to keep.

Optional parameters

• width: Number of counters kept in each array. (Default 8)
• depth: Number of arrays. (Default 7)
• decay: The probability of reducing a counter in an occupied bucket (decay ^ bucket[i].counter). As the counter gets higher, the likelihood of a reduction is lower. (Default 0.9)

Example

redis> TOPK.RESERVE topk 50 2000 7 0.925
OK

Redis Software and Redis Cloud compatibility

| Redis Software | Redis Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> | |:----------------------|:-----------------|:------| | <span title="Supported">✅ Supported</span> | <span title="Supported">✅ Flexible & Annual</span> <span title="Supported">✅ Free & Fixed</nobr></span> | |

Return information

{{< multitabs id="topk-reserve-return-info" tab1="RESP2" tab2="RESP3" >}}

One of the following:

• [Simple string reply]({{< relref "/develop/reference/protocol-spec#simple-strings" >}}) OK if executed correctly.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: incorrect number of arguments, invalid decay value, or key already exists.

-tab-sep-

One of the following:

• [Simple string reply]({{< relref "/develop/reference/protocol-spec#simple-strings" >}}) OK if executed correctly.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: incorrect number of arguments, invalid decay value, or key already exists.

{{< /multitabs >}}