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https://github.com/status-im/nimbus-eth1.git
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42bb640443
By introducing the "shared rocksdb instance" concept to the backend, we can remove the "piggybacking" mode , thus reducing the complexity of database initialisation and opening the possibility of extending how write batching works across kvt/aristo. The change makes explicit the hidden shared state that was previously hiding in closures and provides the first step towards simplifying the "commit/persist" interface of coredb, preparing it for optimizations to reduce the "layering tax" that `forked-layers` introduced.
104 lines
3.3 KiB
Nim
104 lines
3.3 KiB
Nim
# nimbus-eth1
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# Copyright (c) 2023-2025 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed
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# except according to those terms.
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## Kvt DB -- Transaction frames helper
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## ===================================
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##
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{.push raises: [].}
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import
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results,
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./[kvt_desc, kvt_layers]
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc txFrameBegin*(db: KvtDbRef, parent: KvtTxRef): Result[KvtTxRef,KvtError] =
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## Starts a new transaction.
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##
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## Example:
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## ::
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## proc doSomething(db: KvtDbRef) =
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## let tx = db.begin
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## defer: tx.rollback()
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## ... continue using db ...
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## tx.commit()
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##
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let parent = if parent == nil: db.txRef else: parent
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ok KvtTxRef(
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db: db,
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layer: LayerRef(),
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parent: parent,
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)
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proc baseTxFrame*(db: KvtDbRef): KvtTxRef =
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db.txRef
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proc rollback*(
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tx: KvtTxRef; # Top transaction on database
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): Result[void,KvtError] =
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## Given a *top level* handle, this function discards all database operations
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## performed for this transactio. The previous transaction is returned if
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## there was any.
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##
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tx.layer[] = Layer()
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ok()
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proc commit*(
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tx: KvtTxRef; # Top transaction on database
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): Result[void,KvtError] =
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## Given a *top level* handle, this function accepts all database operations
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## performed through this handle and merges it to the previous layer. The
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## previous transaction is returned if there was any.
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##
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doAssert tx.parent != nil, "don't commit base tx"
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mergeAndReset(tx.parent.layer[], tx.layer[])
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ok()
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proc txFramePersist*(
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db: KvtDbRef; # Database
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batch: PutHdlRef;
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) =
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## Persistently store data onto backend database. If the system is running
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## without a database backend, the function returns immediately with an
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## error.
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##
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## The function merges all staged data from the top layer cache onto the
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## backend stage area. After that, the top layer cache is cleared.
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##
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## Finally, the staged data are merged into the physical backend database
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## and the staged data area is cleared. Wile performing this last step,
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## the recovery journal is updated (if available.)
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##
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let be = db.backend
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doAssert not be.isNil, "Persisting to backend requires ... a backend!"
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# Store structural single trie entries
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for k,v in db.txRef.layer.sTab:
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be.putKvpFn(batch, k, v)
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# TODO above, we only prepare the changes to the database but don't actually
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# write them to disk - the code below that updates the frame should
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# really run after things have been written (to maintain sync betweeen
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# in-memory and on-disk state)
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# Done with txRef, all saved to backend
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db.txRef.layer.sTab.clear()
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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