These are the limits a HotKV server enforces. Where a limit comes from a
setting, the default is shown and the setting is linked to the
configuration reference. HotKV Cloud plans add
their own limits, such as memory and connections; see
HotKV Cloud.
| Limit |
Value |
Setting |
| Largest key or string value a client can send |
512 MB by default, up to 4294967295 bytes |
proto-max-bulk-len |
Largest string APPEND or SETRANGE can build |
Same as above |
proto-max-bulk-len |
Highest bit offset (SETBIT, GETBIT, BITFIELD) |
proto-max-bulk-len x 8 - 1 (4294967295 by default) |
proto-max-bulk-len |
Memory for LCS working data |
Up to proto-max-bulk-len; past that the command fails with ERR Insufficient memory, transient memory for LCS exceeds proto-max-bulk-len |
proto-max-bulk-len |
Reply of SRANDMEMBER, HRANDFIELD, ZRANDMEMBER with a negative count |
512 MB; larger counts fail with ERR count is too large, the reply would exceed 512 MB |
no |
| Total data |
No limit by default; at the limit, writes fail with OOM or keys are evicted |
maxmemory, maxmemory-policy |
| Limit |
Value |
Setting |
| Elements in one command (name plus arguments) |
1,048,576 |
no |
| Unprocessed input per client |
1 GB |
client-query-buffer-limit (at least 1 MB) |
| Unprocessed input before a client authenticates |
1 MB |
no |
| Unsent output before a client authenticates |
64 KB |
no |
| Unsent output per client |
normal: no limit; replica: 256 MB hard, 64 MB for 60 s; pubsub: 32 MB hard, 8 MB for 60 s |
client-output-buffer-limit |
| Connected clients |
10,000 by default, 1 to 1,000,000 |
maxclients |
| Addresses to listen on |
16 per bind (and per tls-bind) |
no |
| Client names and library names |
Printable characters, no spaces |
no |
HotKV raises the process’s open-file limit so that maxclients connections
fit. When the operating system does not allow that, CONFIG SET maxclients
fails and names the number of clients that fit.
A client that goes past an input or output limit is disconnected. A request
past the protocol limits gets ERR Protocol error: invalid RESP data and the
connection is closed (see Protocol).
| Limit |
Value |
Setting |
| Databases |
16 by default, 1 to 128 |
databases |
| Databases on a cluster node |
1 by default, 1 to 128 with cluster-databases (set at startup) |
cluster-databases |
| Hash slots |
16384 |
no |
| Cluster node timeout |
15000 ms by default, up to 134217727 ms |
cluster-node-timeout |
Announced address or name (cluster-announce-ip) |
Shorter than 46 characters |
cluster-announce-ip |
| Announced host name |
Shorter than 256 characters; letters, digits, - and . |
cluster-announce-hostname |
For what these mean in practice, see Clustering and
Cluster configuration.
| Limit |
Value |
Setting |
Run time before other clients get BUSY |
5000 ms |
busy-reply-threshold |
Scripts kept from EVAL |
The 500 most recently used; older ones are dropped and EVALSHA of them gets NOSCRIPT. Scripts added with SCRIPT LOAD stay until SCRIPT FLUSH. |
no |
Run time of a library’s top-level code during FUNCTION LOAD |
500 ms |
no |
| Memory a running script may allocate |
A script that allocates too much fails with Lua’s not enough memory error. |
no |
| Nesting of a script’s reply |
1000 levels |
no |
| Limit |
Value |
Setting |
| Slow log entries |
128 |
slowlog-max-len |
| Arguments kept per slow log entry |
32 (the last one says how many more there were), each cut to 128 bytes |
no |
ACL LOG entries |
128, up to 1,000,000 with CONFIG SET |
acllog-max-len |
include nesting in hotkv.conf |
16 levels |
no |
| Limit |
Value |
Bloom filter capacity (BF.RESERVE, BF.INSERT) |
1 to 1,073,741,824 items |
| Bloom filter expansion |
0 to 32768 |
| Size of one Bloom filter layer, Count-Min sketch or Top-K |
4 GB, and no more than the memory the server has free |
