wallet: Store transactions in a separate sqlite table

achow101 commented at 10:52 pm on July 21, 2025: member

The wallet uses SQLite as a key-value store even though SQLite is a powerful relational database engine. This causes us numerous headaches due to the need to serialize multiple fields together, and since record read from the database during loading can come in any order.

Notably, for transactions, if we were able to load them in the transaction order assigned by the wallet, PRs like #27865 would be a bit simpler and easier to reason about.

This PR makes it possible for us to do that by storing transactions in a separate table. This table has a column for each field in CWalletTx, which lets us use a SQL statement like SELECT * FROM transactions ORDER BY pos which guarantees us the order in which the transactions are loaded into the wallet.

The eventual goal is to use SQLite as a relational database with tables that store our keys and other metadata that can reference each other so that the wallet doesn’t just use the database as a storage mechanism. But that is still a work in progress.

This PR makes use of the last client opened features introduced in #32895 to determine when the old record style needs to be upgraded to the new transactions table. This should give us sufficient upgrade-downgrade-upgrade handling to not lose any funds.

Depends on #32763, #32895, #32985, #33031, #33032, #33033

DrahtBot added the label Wallet on Jul 21, 2025

DrahtBot commented at 10:52 pm on July 21, 2025: contributor

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33034.

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Type	Reviewers
Concept ACK	w0xlt, rkrux

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Conflicts

Reviewers, this pull request conflicts with the following ones:

#bitcoin-core/gui/872 (Menu action to export a watchonly wallet by achow101)
#33033 (wallet, sqlite: Encapsulate SQLite statements in a RAII class by achow101)
#33032 (wallet, test: Replace MockableDatabase with in-memory SQLiteDatabase by achow101)
#33008 (wallet: support bip388 policy with external signer by Sjors)
#32985 (wallet: Always rewrite tx records during migration by achow101)
#32966 (Silent Payments: Receiving by Eunovo)
#32895 (wallet: Prepare for future upgrades by recording versions of last client to open and decrypt by achow101)
#32685 (wallet: Allow read-only database access for info and dump commands by PeterWrighten)
#32636 (Split CWallet::Create() into CreateNew and LoadExisting by davidgumberg)
#32489 (wallet: Add exportwatchonlywallet RPC to export a watchonly version of a wallet by achow101)
#29641 (scripted-diff: Use LogInfo over LogPrintf [WIP, NOMERGE, DRAFT] by maflcko)
#28201 (Silent Payments: sending by josibake)
#27865 (wallet: Track no-longer-spendable TXOs separately by achow101)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

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Possible typos and grammar issues:

LastClientFEatures -> LastClientFeatures [correct capitalization of the identifier in the comment so the name is readable/consistent]
InActive -> Inactive [fix capitalization in comment “InMempool needs to be written as InActive(abandoned=false)” to match the actual state name and avoid confusion]

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DrahtBot added the label CI failed on Jul 22, 2025

DrahtBot commented at 0:40 am on July 22, 2025: contributor

🚧 At least one of the CI tasks failed. Task lint: https://github.com/bitcoin/bitcoin/runs/46429203587 LLM reason (✨ experimental): The CI failure is caused by Python lint errors due to unresolved ‘self’ references in test files.

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Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.
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An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

achow101 force-pushed on Jul 22, 2025

DrahtBot removed the label CI failed on Jul 22, 2025

achow101 force-pushed on Jul 23, 2025

w0xlt commented at 9:15 pm on July 23, 2025: contributor

Concept ACK

achow101 force-pushed on Jul 24, 2025

DrahtBot added the label Needs rebase on Jul 29, 2025

achow101 force-pushed on Jul 29, 2025

DrahtBot removed the label Needs rebase on Jul 29, 2025

DrahtBot added the label Needs rebase on Aug 8, 2025

achow101 force-pushed on Aug 8, 2025

DrahtBot removed the label Needs rebase on Aug 8, 2025

DrahtBot added the label Needs rebase on Aug 13, 2025

achow101 force-pushed on Aug 14, 2025

DrahtBot removed the label Needs rebase on Aug 14, 2025

DrahtBot added the label Needs rebase on Aug 16, 2025

achow101 force-pushed on Aug 16, 2025

achow101 force-pushed on Aug 19, 2025

DrahtBot removed the label Needs rebase on Aug 19, 2025

DrahtBot added the label Needs rebase on Sep 23, 2025

wallet: Pass replaces_txid to CommitTransaction outside of mapValue

Instead of updating mapValue with the "replaces_txid" value and passing
the updated mapValue to CommitTransaction, pass the replaces_txid
directly to CommitTransaction which updates mapValue as necessary.

This is prepration for removing mapValue.

74fa2dc513

wallet: Pass comment and comment_to to CommitTransaction

Instead of passing these by setting them in mapValue, pass them directly
to CommitTransaction.

This is preparation for removing mapValue.

788eb75262

wallet: Drop mapValue from CommitTransaction

The values previously passed in mapValue are now parameters to
CommitTransaction so there is no need for mapValue to be passed.

afe0c3bfc8

wallet: Make CWalletTx "from" and "message" member variables

Instead of storing "from" and "message" inside of mapValue, store these
explicitly as members of CWalletTx.

c3758443c1

wallet: Make CWalletTx "comment" and "to" member variables

Instead of storing "comment" and "to" inside of mapValue, store these
expliclty as members of CWalletTx.

fc657ad1f9

wallet: Make CWalletTx "replaces_txid" and "replaced_by_txid" member variables

Instead of storing "replaces_txid" and "replaced_by_txid" as strings inside of
mapValue, store these expliclty as members of CWalletTx.

18228c8047

wallet: Drop mapValue from CWalletTx

It doesn't make sense to be storing relevant metadata variables inside
of a string map in CWalletTx. All of the fields have been pulled out
into separate members, so there is no need for mapValue to stick around.

ae560eb31b

wallet: Drop vOrderForm from CommitTransaction

This parameter is only used to pass in the "Messages" from the GUI.
Instead of making it opaque by putting those into vOrderForm, use a
specific dedicated parameter for providing the messages.

edcb79d175

wallet: Replace CWalletTx's vOrderForm with specific fields

vOrderForm contained 2 kinds of strings: BIP 21 messages, and BIP 70
Payment Requests. Instead of having both inside of a single vOrderForm
field that is opaque, split them into separate std::vector<std::string>
to contain this metadata.

584d191d86

walletdb: Decouple last client record from CLIENT_VERSION

Instead of tying the last client record with the node version, introduce
a separate wallet client version that will be increased as necessary
when new automatic upgrades are introduced.

0c363d6988

wallet: Introduce LastClientFeatures flags and LAST_OPENED_FEATURES record

LastClientFeatures are feature flags indicating what automatic upgrade
features supported by the last client that opened the wallet.

The LAST_OPENED_FEATURES record stores these flags and must be
set to match the exact features supported by the client that opens a
wallet.

b3dd927b95

wallet: Record the supported features of the last client to decrypt a wallet 9eaab2ab56

wallet: Set last opened and decrypted features during migration

Set these flags to avoid the automatic upgrade after migrating.

6ad29f2181

wallet: Always rewrite tx records during migration

Since loading a wallet may change some parts of tx records (e.g. adding
nOrderPos), we should rewrite the records instead of copying them so
that the automatic upgrade does not need to be performed again when the
wallet is loaded.

ee166faf7f

bench, wallet: Make WalletMigration's setup WalletBatch scoped

WalletBatch needs to be in a scope so that it is destroyed before the
database is closed during migration.

db38271097

test: Make duplicating MockableDatabases use cursor and batch

Instead of directly copying the stored records map when duplicating a
MockableDatabase, use a Cursor to read the records, and a Batch to write
them into the new database. This prepares for using SQLite as the
database backend for MockableDatabase.

ae495acf2d

wallet: Make Mockable{Database,Batch} subclasses of SQLite classes

The mocking functionality of MockableDatabase, MockableBatch, and
MockableCursor was not really being used. These are changed to be
subclasses of their respective SQLite* classes and will use in-memory
SQLite databases so that the tests are more representative of actual
database behavior.

MockableCursor is removed as there are no overrides needed in
SQLiteCursor for the tests.

bf34cf1756

walletdb: Remove m_mock from SQLiteDatabase 36f8b7da56

sqlite: Add SQLiteStatement RAII class

This class will be used to encapsulate a sqlite3_stmt

b461c15baf

sqlite: Make Column template function ec443688c2

sqlite: Refactor ReadPragmaInteger to use SQLiteStatement 0dbf3fe6b1

sqlite: Use SQLiteStatement in PRAGMA integrity_check f9a8fb7a46

sqlite: Use SQLiteStatement in check_main_stmt af23ca9713

sqlite: Have SQLiteCursor store SQLiteStatement 16e6b6cfcc

sqlite: Replace remaining sqlite3_stmt usage with SQLiteStatement 49c87b1b8d

sqlite: Refactor common writing code from WriteKey and ExecStatement

WriteKey and ExecStatement use the same code for the actual execution of
the statement. This is refactored into a separate function, also called
ExecStatement, and the original ExecStatement renamed to
ExecEraseStatement as it is only used by the erase functions.

3a94c9db37

sqlite: Inline BindBlobToStatement and SpanFromBlob a30c137c2c

util: Add span constructor to (W)Txid 6accae034a

sqlite: Make SQLiteStatement::Bind a template function

We will need to bind data types other than blob

818989093d

sqlite: Make SQLiteDatabase::Column an std::optional

To handle columns containing NULL values, Column needs to return some
value representing NULL, so make it a std::optional.

07cac74e13

sqlite: Add additional blob types to SQLiteStatement::Column

Not all blob data types fit in ColumnBlob, so we need additional
template type requirements to match those.

ff47eea527

wallet: Add Un/Serialize to TxState structs 5090f37ba2

wallet: Add new serialization format functions for TxState 2a38513899

sqlite: Create a 'transactions' table if it does not exist 9818bb4663

sqlite: Add functions and statements for transactions table 809e853e90

sqlite: Iterate the transactions table with SQLiteCursor 85f67a414e

walletdb: Add functions to modify transactions table d9e96fd4b5

test: Include sql transactions table in DuplicateMockDatabase 1ce7c73063

wallet: Also write to the new transactions table 5a2421055c

wallet: Perform automatic upgrade to using the transactions table 3166bb6dc2

walletdb: Load from transactions table and use original tx for upgrade

When loading a wallet, always load from the transactions table, except
when loading a legacy wallet for migration.

The original 'tx' records are only used to upgrade to the transactions
table if an upgraded is necessary.

a25557a731

achow101 force-pushed on Sep 23, 2025

DrahtBot removed the label Needs rebase on Sep 24, 2025

rkrux commented at 8:14 am on October 9, 2025: contributor

Concept ACK a25557a

I have gone through the PR description and have skimmed over the commit messages as of now. At the outset, I find myself agreeing with the intent here. I am not aware of a strong enough reason to keep using SQLite as a KVS for all purposes, using its relational database properties for wallet transactions seem like a good start. I did notice some serialisation specifics of transaction properties in a couple previous PRs that I didn’t fully understand why were required; it could be a lot cleaner and explicit in implementation if using SQLite as an RDBMS can avoid the need for doing those specific serialisations.

wallet: Store transactions in a separate sqlite table #33034

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