Fix cluster info sent stats for message with light header

[hpatro]

This issue only impacted two message type (CLUSTERMSG_TYPE_PUBLISH / CLUSTERMSG_TYPE_PUBLISHSHARD) as those were the only message type uses light message header where the CLUSTER INFO stats had missing information of sent/received messages of that type.

Before

cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:3
cluster_size:3
cluster_current_epoch:2
cluster_my_epoch:0
cluster_stats_messages_ping_sent:20
cluster_stats_messages_pong_sent:22
cluster_stats_messages_meet_sent:2
cluster_stats_messages_sent:44
cluster_stats_messages_ping_received:22
cluster_stats_messages_pong_received:22
cluster_stats_messages_received:44
total_cluster_links_buffer_limit_exceeded:0

After

cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:3
cluster_size:3
cluster_current_epoch:2
cluster_my_epoch:1
cluster_stats_messages_ping_sent:20
cluster_stats_messages_pong_sent:23
cluster_stats_messages_meet_sent:2
**cluster_stats_messages_publish_sent:2**
cluster_stats_messages_sent:47
cluster_stats_messages_ping_received:23
cluster_stats_messages_pong_received:22
cluster_stats_messages_received:45
total_cluster_links_buffer_limit_exceeded:0

[hpatro]

@zuiderkwast let me know if we can get the type without modifying the method signature.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.95%. Comparing base (d99457c) to head (88d14a3).
Report is 18 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1563      +/-   ##
============================================
+ Coverage     70.94%   70.95%   +0.01%     
============================================
  Files           120      121       +1     
  Lines         65004    65130     +126     
============================================
+ Hits          46116    46215      +99     
- Misses        18888    18915      +27     

Files with missing lines	Coverage Δ
src/cluster_legacy.c	87.25% <100.00%> (+0.34%)	⬆️

... and 24 files with indirect coverage changes

[zuiderkwast]

Good idea. I replies to your question in a comment below.

We don't need to distinguish the heavy/light variants in the stats counter, because we have some other stats counting the bytes?

[hpatro]

Good idea. I replies to your question in a comment below.

We don't need to distinguish the heavy/light variants in the stats counter, because we have some other stats counting the bytes?

I initially thought of adding light_{type}_sent/light_{type}_received and keep the messages with regular hdr stats as is. I felt it's not that useful for Valkey users but helps with debugging for us. WDYT ?

[zuiderkwast]

I initially thought of adding light_{type}_sent/light_{type}_received and keep the messages with regular hdr stats as is. I felt it's not that useful for Valkey users but helps with debugging for us. WDYT ?

I agree it's not useful for users. The light/heavy message type is an implementation detail. The bytes sent/received over the cluster bus can be interesting for users. We have that? I can't see it in the CLUSTER INFO man page.

Shall we mention it as a bugfix in the release notes? Backport to 8.0?

[hpatro]

I initially thought of adding light_{type}_sent/light_{type}_received and keep the messages with regular hdr stats as is. I felt it's not that useful for Valkey users but helps with debugging for us. WDYT ?

I agree it's not useful for users. The light/heavy message type is an implementation detail. The bytes sent/received over the cluster bus can be interesting for users. We have that? I can't see it in the CLUSTER INFO man page.

Do you mean the CLUSTER LINKS thing ? I don't see a sent/received stats though. We should add it I guess.

Shall we mention it as a bugfix in the release notes? Backport to 8.0?

Yeah, I think we should backport it to 8.

[zuiderkwast]

Do you mean the CLUSTER LINKS thing ? I don't see a sent/received stats though. We should add it I guess.

I wasn't aware of CLUSTER LINK. Thanks. Looks like it shows only currently connected nodes. I guess we could add sent/received bytes there.

I was thinking of a total sent/received over the cluster bus, probably in CLUSTER INFO.

Perhaps we should wait until anyone actually requests it. :)

[enjoy-binbin]

LGTM.

[hpatro]

Backport to 8.0 PR: #1571