It turns out that we often save lots of states in the database that are
the result of empty slot processing only - here, we make sure to only
save a state if a block follows - this fixes several issues:
* empty slot states are not always pruned leading to state database size
explosion
* storing states is (very) slow which slows down processing in general,
so we should only do it when it's likely to be useful
* attestation processing doesn't get stuck on saving random states that
won't appear in the chain history
about 40% better slot processing times (with LTO enabled) - these don't
do BLS but are used
heavily during replay (state transition = slot + block transition)
tests using a recent medalla state and advancing it 1000 slots:
```
./ncli slots --preState2:state-302271-3c1dbf19-c1f944bf.ssz --slot:1000
--postState2:xx.ssz
```
pre:
```
All time are ms
Average, StdDev, Min, Max, Samples,
Test
Validation is turned off meaning that no BLS operations are performed
39.236, 0.000, 39.236, 39.236, 1,
Load state from file
0.049, 0.002, 0.046, 0.063, 968,
Apply slot
256.504, 81.008, 213.471, 591.902, 32,
Apply epoch slot
28.597, 0.000, 28.597, 28.597, 1,
Save state to file
```
cast:
```
All time are ms
Average, StdDev, Min, Max, Samples,
Test
Validation is turned off meaning that no BLS operations are performed
37.079, 0.000, 37.079, 37.079, 1,
Load state from file
0.042, 0.002, 0.040, 0.090, 968,
Apply slot
215.552, 68.763, 180.155, 500.103, 32,
Apply epoch slot
25.106, 0.000, 25.106, 25.106, 1,
Save state to file
```
cast+rewards:
```
All time are ms
Average, StdDev, Min, Max, Samples,
Test
Validation is turned off meaning that no BLS operations are performed
40.049, 0.000, 40.049, 40.049, 1,
Load state from file
0.048, 0.001, 0.045, 0.060, 968,
Apply slot
164.981, 76.273, 142.099, 477.868, 32,
Apply epoch slot
28.498, 0.000, 28.498, 28.498, 1,
Save state to file
```
cast+rewards+shr
```
All time are ms
Average, StdDev, Min, Max, Samples,
Test
Validation is turned off meaning that no BLS operations are performed
12.898, 0.000, 12.898, 12.898, 1,
Load state from file
0.039, 0.002, 0.038, 0.054, 968,
Apply slot
139.971, 68.797, 120.088, 428.844, 32,
Apply epoch slot
24.761, 0.000, 24.761, 24.761, 1,
Save state to file
```
* combine ncli_hash_tree_root and ncli_pretty into ncli_ssz
* disable ncli_query building by default
* fold ncli_transition into ncli_ssz and rename to ncli