* Replace registerCustomScalarFunction with createCustomFunction
The nice thing about `registerCustomScalarFunction` and
`registerCustomScalarFunction` was that it kept the sqlite calls
of type sqlite3_value_xxx inside kvstore_sqlite.
The big downside however is that the "custom" call is awfully
specific due to the specific function signature it demands.
It is likely that for each different use case, a new version
needs to be added.
In this PR the code gets altered to `createCustomFunction` which
allows to just create a custom function with directly xFunc
signature of sqlite. The downside of this is that you still need
to import sqlite_abi in your local code to have access to each of
the sqlite3_value_xxx and sqlite3_result_xxx calls. These could of
course also be wrapped.
* Fix custom sql func test
Currently only setting `--styleCheck:hint` as there are some
dependency fixes required and the compiler seems to trip over the
findnode MessageKind, findnode Message field and the findNode
proc. Also over protocol.Protocol usage.
Storing large blobs in a "WITHOUT ROWID" table turns out to be extremely
slow when the tree must be rebalanced.
* Split out keystore capability into separate interface, making each
keystore a separate instance
* Disable "WITHOUT ROWID" optimization by default
* Implement prefix lookup that allows iterating over all values with a
certain prefix in their key
If the database is locked for reading, as it is when step returns ROW,
writes cannot checkpoint the wal leading to ever-increasing wal sizes
and a long delay at shutdown.
By resetting the transaction early, writes become more independent of
reads, memory is released earlier and wal can be checkpointed.
* port kvstore from nim-beacon-chain
* remove old database backends
* use kvstore in trie database
* add sqlite dep
* avoid template param double evaluation
* clean up heterogenous lookup todo