Begins an incremental save of the Bloom filter.

This command is useful for large Bloom filters that cannot fit into the [DUMP]({{< relref "/commands/dump" >}}) and [RESTORE]({{< relref "/commands/restore" >}}) model.

The first time this command is called, the value of iter should be 0.

This command returns successive (iter, data) pairs until (0, NULL) to indicate completion.

Required arguments

<details open><summary><code>key</code></summary>

is key name for a Bloom filter to save.

</details> <details open><summary><code>iterator</code></summary>

Iterator value; either 0 or the iterator from a previous invocation of this command

</details>

Examples

{{< highlight bash >}} redis> BF.RESERVE bf 0.1 10 OK redis> BF.ADD bf item1

1. (integer) 1 redis> BF.SCANDUMP bf 0
2. (integer) 1
3. "\x01\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x05\x00\x00\x00\x02\x00\x00\x00\b\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x9a\x99\x99\x99\x99\x99\xa9?J\xf7\xd4\x9e\xde\xf0\x18@\x05\x00\x00\x00\n\x00\x00\x00\x00\x00\x00\x00\x00" redis> BF.SCANDUMP bf 1
4. (integer) 9
5. "\x01\b\x00\x80\x00\x04 \x00" redis> BF.SCANDUMP bf 9
6. (integer) 0
7. "" redis> DEL bf (integer) 1 redis> BF.LOADCHUNK bf 1 "\x01\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x05\x00\x00\x00\x02\x00\x00\x00\b\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x9a\x99\x99\x99\x99\x99\xa9?J\xf7\xd4\x9e\xde\xf0\x18@\x05\x00\x00\x00\n\x00\x00\x00\x00\x00\x00\x00\x00" OK redis> BF.LOADCHUNK bf 9 "\x01\b\x00\x80\x00\x04 \x00" OK redis> BF.EXISTS bf item1 (integer) 1 {{< / highlight >}}

Python code: {{< highlight bash >}} chunks = [] iter = 0 while True: iter, data = BF.SCANDUMP(key, iter) if iter == 0: break else: chunks.append([iter, data])

Load it back

for chunk in chunks: iter, data = chunk BF.LOADCHUNK(key, iter, data) {{< / highlight >}}

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="bf-scandump-return-info" tab1="RESP2" tab2="RESP3" >}}

One of the following:

• [Array reply]({{< relref "/develop/reference/protocol-spec#arrays" >}}): a two-element array of an [Integer reply]({{< relref "/develop/reference/protocol-spec#integers" >}}) (Iterator) and a [Bulk string reply]({{< relref "/develop/reference/protocol-spec#bulk-strings" >}}) (Data).
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: invalid arguments, the key was not found, or the key is of the wrong type.

The Iterator is passed as input to the next invocation of BF.SCANDUMP. If Iterator is 0, then it means iteration has completed.

The iterator-data pair should also be passed to [BF.LOADCHUNK]({{< relref "commands/bf.loadchunk/" >}}) when restoring the filter.

-tab-sep-

One of the following:

• [Array reply]({{< relref "/develop/reference/protocol-spec#arrays" >}}): a two-element array of an [Integer reply]({{< relref "/develop/reference/protocol-spec#integers" >}}) (Iterator) and a [Bulk string reply]({{< relref "/develop/reference/protocol-spec#bulk-strings" >}}) (Data).
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: invalid arguments, the key was not found, or the key is of the wrong type.

The Iterator is passed as input to the next invocation of BF.SCANDUMP. If Iterator is 0, then it means iteration has completed.

The iterator-data pair should also be passed to [BF.LOADCHUNK]({{< relref "commands/bf.loadchunk/" >}}) when restoring the filter.

{{< /multitabs >}}