The following performance gains were measured using the new benchmark
test.
```
name old time/op new time/op delta
ChanUpdatesInHorizon-native-sqlite-10 18.5s ± 3% 2.0s ± 5% -89.11% (p=0.000 n=9+9)
ChanUpdatesInHorizon-native-postgres-10 59.0s ± 3% 0.8s ±10% -98.65% (p=0.000 n=10+9)
```
Let the helper method only take the params it needs so that we dont need
to construct an entire models.ChannelEdgeInfo object to pass to it. This
will be useful later on.
Here we adjust the ForEachNodeCached graph DB method to pass in a node's
addresses into the provided call-back if requested. This will allow us
to improve the performance of node/channel iteration in the autopilot
subserver.
Previously, ForEachNodeCached would batch fetch node _feature_ data but
would still fetch the channel set of each node in a node-by-node fashion
which is not ideal. So this commit updates this method to make use of
the new sqldb.ExecuteCollectAndBatchWithSharedDataQuery helper. It lets
us batch load channel data for a range of node IDs.
This _greatly_ improves the performance of the method.
In this commit, we update the SQLStore's ForEachNodeCacheable and
ForEachNodeCached methods to use batch collection for node feature bits.
This results in the following performance gains:
```
name old time/op new time/op delta
ForEachNodeCacheable-native-sqlite-10 184ms ± 2% 145ms ±10% -21.45% (p=0.000 n=10+10)
ForEachNodeCacheable-native-postgres-10 697ms ± 8% 51ms ± 4% -92.68% (p=0.000 n=9+10)
```
This commit is a pure refactor. Here all we are doing is removing the
old `pageSize` constant used in the SQLStore code and instead using the
value provided in the QueryConfig struct.
We rename this helper along the config types & helper types for it
because the word "page" is used more often in the context of paging
through results using an offset and limit whereas this helper is
specifically used to split up the slice in queries of the form
"WHERE x in []slice". We do this rename so that there is mimimal
confusion in contexts where we use batching along with actual paging.
The config struct is also renamed to QueryConfig in preparation for it
holding more config options.
Here, we add a new `buildNodeWithBatchData` helper method that can be
used to construct a `models.LightningNode` object using pre-fetched
batch data. The existing `buildNode` method is then adjusted to use this
new helper.
In this commit, we add the queries that will be needed to batch-fetch
the data of a set of nodes. The logic for using these new queries is
also added but not used yet.
In this commit, we remove the LEFT JOIN query that was used for fetching
a nodes addresses. The reason it was used before was to ensure that we'd
get an empty address list if the node did exist but had no addresses.
This was for the purposes of the `AddrsForNode` method since it needs to
return false/true to indicate if the given node exists.
Use the new `SLICES` directive to add a DeleteChannels query which takes
a set of DB channel IDs. Then replace all our calls to DeleteChannel
with a paginated call to DeleteChannels.
This commit adds a new GetChannelsByOutpoints query which takes a slice
of outpoint strings. This lets us then update PruneGraph to use
paginated calls to GetChannelsByOutpoints instead of making one DB call
per outpoint.
