[master < T1227] Optimise iteration

[Ignition]

For example following query:

UNWIND RANGE (1, 500) AS i CREATE ();
MATCH (),(),() RETURN COUNT(*);

went from 6.549 seconds to 3.625 seconds

To keep docs changelog up to date, one more thing to do:

• Write a release note here, including added/changed clauses --> "Optimizations to scanning vertices"
• Tag someone from docs team in the comments

[andrejtonev]

Cool!

[gitbuda]

@vpavicic this probably requires a bit more attention in the changelog because it's a significant improvement (100%) in the case where there is a lot of iterations over graph entities, the query @Ignition put into the description is just one example, but I think this optimization applies in many cases 👀 @Ignition maybe you can add a bit more details from the user perspective (e.g. what's the real world query that will benefit out of this) 😃

[vpavicic]

@Ignition Do you have any more queries to show the usage/benefits?

[Ignition]

@vpavicic not really, the query I optimized around demonstrated ScanAll performance gain. But I expect real usecase would be more complex. Hence IMO other parts of the plan would dominate the execution profile.