Last night we hit a rare case of failed convergence.
f was out of sync with the rest of the world.
f: upi=[b,g,f] repairing=[a,c]
The "rest of the world" used a larger chain at:
*: upi=[c,b,g,a], repairing=[f]
And f refused to join the larger chain because of the way that
IsRelevantToMe_p was being calculated before this commit.
Hrrrm, though, I'm not convinced that this particular problem
is fixed 100% by this patch. What if the chain lengths were
the same but also UPI incompatible? e.g. if I remove 'a' from
the "real world (in the partition simulator)" example above:
f: upi=[b,g,f] repairing=[c]
*: upi=[c,b,g], repairing=[f]
Hrmmmmm, I may need to reintroduce the my-recent-adopted-projection-
flapping-like-counter thingie to try to break this kind of
incompatible deadlock.
See comments added in this commit at A40.
So far, I've been doing CP mode testing with a handful of (very useful)
network partition combinations using:
machi_chain_manager1_converge_demo:t(3, [{private_write_verbose,true}, {consistency_mode, cp_mode}, {witnesses, [a]}]).
Next steps:
* Expand number & types of partitions
* Expand to chain lengths of 5 and beyond
So, I'm 50% sure this is a good idea for CP mode: if there's
a later public projection than P_current, then who knows what
we might have missed. So, call make_zerf() to find out the
absolute latest. Problem: flapping state appears to be lost,
booo.
If we use verbose output from:
machi_chain_manager1_converge_demo:t(3, [{private_write_verbose,true}, {consistency_mode, cp_mode}, {witnesses, [a]}]).
And use:
tail -f typescript_file | egrep --line-buffered 'SET|attempted|CONFIRM'
... then we can clearly see a chain safety violation when moving from
epoch 81 -> 83. I need to add more smarts to the safety checking,
both at the individual transition sanity check and at the converge_demo
overall rolling sanity check.
Key to output: CONFIRM by epoch {num} {csum} at {UPI} {Repairing}
SET # of FLUs = 3 members [a,b,c]).
CONFIRM by epoch 1 <<96,161,96,...>> at [a,b] [c]
CONFIRM by epoch 5 <<134,243,175,...>> at [b,c] []
CONFIRM by epoch 7 <<207,93,225,...>> at [b,c] []
CONFIRM by epoch 47 <<60,142,248,...>> at [b,c] []
SET partitions = [{c,b},{c,a}] (1 of 2) at {22,3,34}
CONFIRM by epoch 81 <<223,58,184,...>> at [a,b] []
SET partitions = [{b,c},{b,a}] (2 of 2) at {22,3,38}
CONFIRM by epoch 83 <<33,208,224,...>> at [a,c] []
SET partitions = []
CONFIRM by epoch 85 <<173,179,149,...>> at [a,c] [b]
Also, add more misc details to the 'react' breadcrumb trail. Also,
save get(react) results into dbg2 whenever we write a private projection,
very valuable for debugging.
Also: cleanup PULSE code, add regression commands as option and
controls with some new environment variables. These regression
sequences were responsbile for several fruitful debugging sessions,
so we keep them for posterity and for their ability (with new seeds
and PULSE) to find new interleavings.
So, the PULSE test is failing, which is good. However, I believe
that the failures are all due to the model now being *too strict*.
The model is now catching failures which are now benign, I think.
{bummer_NOT_DISJOINT,{[a,b,b,c,d],
[{a,not_in_this_epoch},
{b,not_in_this_epoch},
{c,"[{epoch,1546},{author,c},{upi,[c]},{repair,[b]},{down,[a,d]},{d,[{ps,[{a,c},{c,a},{a,d},{b,d},{c,d}]},{nodes_up,[b,c]}]},{d2,[]}]"},
{d,"[{epoch,1546},{author,d},{upi,[d]},{repair,[a,b]},{down,[c]},{d,[{ps,[{c,b},{d,c}]},{nodes_up,[a,b,d]}]},{d2,[]}]"}]}}},
In this and all other examples, the UPIs are disjoint but the
repairs are not disjoint. I believe the model ought to be
ignoring the repair list.
{bummer_NOT_DISJOINT,{[a,a,b],
[{a,"[{epoch,1174},{author,a},{upi,[a]},{repair,[]},{down,[b]},{d,[{ps,[{a,b},{b,a}]},{nodes_up,[a]}]},{d2,[]}]"},
{b,"[{epoch,1174},{author,b},{upi,[b]},{repair,[a]},{down,[]},{d,[{ps,[]},{nodes_up,[a,b]}]},{d2,[]}]"}]}}},
or
{bummer_NOT_DISJOINT,{[c,c,e],
[{a,not_in_this_epoch},
{b,not_in_this_epoch},
{c,"[{epoch,1388},{author,c},{upi,[c]},{repair,[]},{down,[a,b,d,e]},{d,[{ps,[{a,b},{a,c},{c,a},{a,d},{d,a},{e,a},{c,b},{b,e},{e,b},{c,d},{e,c},{e,d}]},{nodes_up,[c]}]},{d2,[]}]"},
{d,not_in_this_epoch},
{e,"[{epoch,1388},{author,e},{upi,[e]},{repair,[c]},{down,[a,b,d]},{d,[{ps,[{a,b},{b,a},{a,c},{c,a},{a,d},{d,a},{a,e},{e,a},{b,c},{c,b},{b,d},{b,e},{e,b},{c,d},{d,c},{d,e},{e,d}]},{nodes_up,[c,e]}]},{d2,[]}]"}]}}},
