docs: add note on compound executor

[cristianmtr]

No description provided.

[github-actions]

Latency summary

Current PR yields:

• 😶 index QPS at 1097, delta to last 2 avg.: -1%
• 😶 query QPS at 44, delta to last 2 avg.: -2%
• 😶 dam extend QPS at 40059, delta to last 2 avg.: -3%
• 😶 avg flow time within 1.6938 seconds, delta to last 2 avg.: +2%
• 🐢🐢 import jina within 0.4201 seconds, delta to last 2 avg.: -13%

Breakdown

Version	Index QPS	Query QPS	DAM Extend QPS	Avg Flow Time (s)	Import Time (s)
current	1097	44	40059	1.6938	0.4201
2.1.0	1106	44	41335	1.7998	0.4737
2.0.24	1113	45	41809	1.5042	0.4929

Backed by latency-tracking. Further commits will update this comment.

[codecov]

Codecov Report

Merging #3406 (ce0a7ba) into master (c939bf3) will increase coverage by 0.41%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3406      +/-   ##
==========================================
+ Coverage   89.85%   90.26%   +0.41%     
==========================================
  Files         152      152              
  Lines       10841    10908      +67     
==========================================
+ Hits         9741     9846     +105     
+ Misses       1100     1062      -38     

Flag	Coverage Δ
daemon	45.70% <ø> (+0.15%)	⬆️
jina	90.25% <ø> (+0.41%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
jina/hubble/hubio.py	88.07% <0.00%> (-0.78%)	⬇️
jina/peapods/peas/__init__.py	85.89% <0.00%> (-0.09%)	⬇️
jina/parsers/base.py	100.00% <0.00%> (ø)
jina/hubble/helper.py	90.06% <0.00%> (ø)
jina/jaml/__init__.py	95.57% <0.00%> (+0.18%)	⬆️
jina/peapods/zmq/__init__.py	89.04% <0.00%> (+0.23%)	⬆️
jina/types/arrays/neural_ops.py	89.91% <0.00%> (+0.92%)	⬆️
jina/peapods/runtimes/gateway/http/app.py	92.40% <0.00%> (+1.26%)	⬆️
jina/clients/base/__init__.py	92.42% <0.00%> (+1.51%)	⬆️
jina/peapods/runtimes/zmq/asyncio.py	92.98% <0.00%> (+1.75%)	⬆️
... and 8 more

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[hanxiao]

isn't this here already?

if the current tab not enough, please put your new content in that tab.

addressed

[hanxiao]

I feel like the guide in docs/advanced/experimental/compound_executors.md is not complete? it introduces what is CompoundExecutor, but it does not give any MWU to showcase it, or reference.

[cristianmtr]

I feel like the guide in docs/advanced/experimental/compound_executors.md is not complete? it introduces what is CompoundExecutor, but it does not give any MWU to showcase it, or reference.

Expanded with a basic example.

[alexcg1]

Typo

[hanxiao]

minor revision

[hanxiao]

Suggested change

	- combining a Storage and a Search Indexer in one, for easier access, scaling etc.
	- combining a custom ranker and an Indexer in one, for cases where `top_k` is not achieved after a ranking process filters out results
	- having Indexers that store multiple level of granularity in one Executor, for easier lookup and custom logic
	If you want to develop a `CompoundExecutor`-type Executor based on one of the Executors existing in Jina Hub, you have to copy-paste the code of the classes you need into your own Executor's package.
	This is because, for now, the Executors in Jina Hub can **not** be imported as Python modules.
	- combining a Storage and a Search Indexer in one, for easier access, scaling etc.
	- combining a custom ranker and an Indexer in one, for cases where `top_k` is not achieved after a ranking process filters out results
	- having Indexers that store multiple levels of granularity in one Executor, for easier lookup and custom logic
	````{caution}
	If you want to develop a `CompoundExecutor`-type Executor based on one of the Executors existing in Jina Hub, you have to copy-paste the code of the classes you need into your own Executor's package.
	This is because, for now, the Executors in Jina Hub can **not** be imported as Python modules.

[hanxiao]

seems my "` * 4" does not work on Github IDE, the closing quote is eaten by it

[hanxiao]

few glitches, let me directly working on this branch