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zcash_client_sqlite: Only select notes for which witnesses can be constructed. 

This change modifies the implementation of `get_spendable_sapling_notes`
and `select_spendable_sapling_notes` to only return notes at positions
where the associated note commitment tree shard has been fully scanned.
This is slightly more conservative than it needs to be, because
there could be cases where witnesses imported into the tree in the
`shardtree_support` migration cover the complete range of a subtree (and
hence that subtree doesn't need to be re-scanned). However, we can't
detect or depend upon that condition in general without attempting to
create a witness for each note retrieved.

A possible alternative to this approach would be to not bound our query
results on the requested total, and instead attempt to construct a
witness for each note we retrieve, skipping the note if we cannot
construct a witness. However, given that accessing the note commitment
tree can be a costly operation requiring nontrivial deserialization
costs, the more conservative database-oriented approach is perhaps
better.
This commit is contained in:
Kris Nuttycombe 2023-08-09 13:54:07 -06:00
parent 104577c108
commit 50ea2a5b0f
4 changed files with 139 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
zcash_client_sqlite/src/wallet/init.rs
View File

@ -353,14 +353,14 @@ mod tests {
use zcash_client_backend::{
address::RecipientAddress,
data_api::WalletRead,
data_api::{scanning::ScanPriority, WalletRead},
encoding::{encode_extended_full_viewing_key, encode_payment_address},
keys::{sapling, UnifiedFullViewingKey, UnifiedSpendingKey},
};
use zcash_primitives::{
block::BlockHash,
consensus::{BlockHeight, BranchId, Parameters},
consensus::{BlockHeight, BranchId, NetworkUpgrade, Parameters},
transaction::{TransactionData, TxVersion},
zip32::sapling::ExtendedFullViewingKey,
};
@ -368,6 +368,7 @@ mod tests {
use crate::{
error::SqliteClientError,
tests::{self, network},
wallet::scanning::priority_code,
AccountId, WalletDb,
};
@ -558,6 +559,33 @@ mod tests {
}
let expected_views = vec![
// v_sapling_shard_unscanned_ranges
format!(
"CREATE VIEW v_sapling_shard_unscanned_ranges AS
SELECT
shard.shard_index,
shard.shard_index << 16 AS start_position,
(shard.shard_index + 1) << 16 AS end_position_exclusive,
IFNULL(prev_shard.subtree_end_height, {}) AS subtree_start_height,
shard.subtree_end_height AS subtree_end_height,
shard.contains_marked,
scan_queue.block_range_start,
scan_queue.block_range_end,
scan_queue.priority
FROM sapling_tree_shards shard
LEFT OUTER JOIN sapling_tree_shards prev_shard
ON shard.shard_index = prev_shard.shard_index + 1
INNER JOIN scan_queue ON
(scan_queue.block_range_start BETWEEN subtree_start_height AND shard.subtree_end_height) OR
((scan_queue.block_range_end - 1) BETWEEN subtree_start_height AND shard.subtree_end_height) OR
(
scan_queue.block_range_start <= prev_shard.subtree_end_height
AND (scan_queue.block_range_end - 1) >= shard.subtree_end_height
)
WHERE scan_queue.priority != {}",
u32::from(tests::network().activation_height(NetworkUpgrade::Sapling).unwrap()),
priority_code(&ScanPriority::Scanned),
),
// v_transactions
"CREATE VIEW v_transactions AS
WITH
@ -649,7 +677,7 @@ mod tests {
LEFT JOIN sent_note_counts
ON sent_note_counts.account_id = notes.account_id
AND sent_note_counts.id_tx = notes.id_tx
GROUP BY notes.account_id, transactions.id_tx",
GROUP BY notes.account_id, transactions.id_tx".to_owned(),
// v_tx_outputs
"CREATE VIEW v_tx_outputs AS
SELECT sapling_received_notes.tx AS id_tx,
@ -693,7 +721,7 @@ mod tests {
ON (sent_notes.tx, sent_notes.output_pool, sent_notes.output_index) =
(sapling_received_notes.tx, 2, sapling_received_notes.output_index)
WHERE sapling_received_notes.is_change IS NULL
OR sapling_received_notes.is_change = 0"
OR sapling_received_notes.is_change = 0".to_owned(),
];
let mut views_query = db_data
@ -706,7 +734,7 @@ mod tests {
let sql: String = row.get(0).unwrap();
assert_eq!(
re.replace_all(&sql, " "),
re.replace_all(expected_views[expected_idx], " ")
re.replace_all(&expected_views[expected_idx], " ")
);
expected_idx += 1;
}
@ -971,7 +999,7 @@ mod tests {
wdb.conn.execute(
"INSERT INTO transactions (block, id_tx, txid, raw) VALUES (0, 0, :txid, :tx_bytes)",
named_params![
":txid": tx.txid().as_ref(),
":txid": tx.txid().as_ref(),
":tx_bytes": &tx_bytes[..]
],
)?;

6
zcash_client_sqlite/src/wallet/init/migrations.rs
View File

@ -9,6 +9,7 @@ mod sent_notes_to_internal;
mod shardtree_support;
mod ufvk_support;
mod utxos_table;
mod v_sapling_shard_unscanned_ranges;
mod v_transactions_net;
use schemer_rusqlite::RusqliteMigration;
@ -36,6 +37,8 @@ pub(super) fn all_migrations<P: consensus::Parameters + 'static>(
// received_notes_nullable_nf
// / | \
// shardtree_support nullifier_map sapling_memo_consistency
// |
// v_sapling_shard_unscanned_ranges
vec![
Box::new(initial_setup::Migration {}),
Box::new(utxos_table::Migration {}),
@ -58,5 +61,8 @@ pub(super) fn all_migrations<P: consensus::Parameters + 'static>(
Box::new(sapling_memo_consistency::Migration {
params: params.clone(),
}),
Box::new(v_sapling_shard_unscanned_ranges::Migration {
params: params.clone(),
}),
]
}

75
zcash_client_sqlite/src/wallet/init/migrations/v_sapling_shard_unscanned_ranges.rs Normal file
View File

@ -0,0 +1,75 @@
//! This migration adds a view that returns the un-scanned ranges associated with each sapling note
//! commitment tree shard.
use std::collections::HashSet;
use schemer_rusqlite::RusqliteMigration;
use uuid::Uuid;
use zcash_client_backend::data_api::scanning::ScanPriority;
use zcash_primitives::consensus;
use crate::wallet::{init::WalletMigrationError, scanning::priority_code};
use super::shardtree_support;
pub(super) const MIGRATION_ID: Uuid = Uuid::from_u128(0xfa934bdc_97b6_4980_8a83_b2cb1ac465fd);
pub(super) struct Migration<P> {
pub(super) params: P,
}
impl<P> schemer::Migration for Migration<P> {
fn id(&self) -> Uuid {
MIGRATION_ID
}
fn dependencies(&self) -> HashSet<Uuid> {
[shardtree_support::MIGRATION_ID].into_iter().collect()
}
fn description(&self) -> &'static str {
"Adds a view that returns the un-scanned ranges associated with each sapling note commitment tree shard."
}
}
impl<P: consensus::Parameters> RusqliteMigration for Migration<P> {
type Error = WalletMigrationError;
fn up(&self, transaction: &rusqlite::Transaction) -> Result<(), Self::Error> {
transaction.execute_batch(
&format!(
"CREATE VIEW v_sapling_shard_unscanned_ranges AS
SELECT
shard.shard_index,
shard.shard_index << 16 AS start_position,
(shard.shard_index + 1) << 16 AS end_position_exclusive,
IFNULL(prev_shard.subtree_end_height, {}) AS subtree_start_height,
shard.subtree_end_height AS subtree_end_height,
shard.contains_marked,
scan_queue.block_range_start,
scan_queue.block_range_end,
scan_queue.priority
FROM sapling_tree_shards shard
LEFT OUTER JOIN sapling_tree_shards prev_shard
ON shard.shard_index = prev_shard.shard_index + 1
INNER JOIN scan_queue ON
(scan_queue.block_range_start BETWEEN subtree_start_height AND shard.subtree_end_height) OR
((scan_queue.block_range_end - 1) BETWEEN subtree_start_height AND shard.subtree_end_height) OR
(
scan_queue.block_range_start <= prev_shard.subtree_end_height
AND (scan_queue.block_range_end - 1) >= shard.subtree_end_height
)
WHERE scan_queue.priority != {}",
u32::from(self.params.activation_height(consensus::NetworkUpgrade::Sapling).unwrap()),
priority_code(&ScanPriority::Scanned),
)
)?;
Ok(())
}
fn down(&self, transaction: &rusqlite::Transaction) -> Result<(), Self::Error> {
transaction.execute_batch("DROP VIEW v_sapling_shard_unscanned_ranges;")?;
Ok(())
}
}

36
zcash_client_sqlite/src/wallet/sapling.rs
View File

@ -139,7 +139,15 @@ pub(crate) fn get_spendable_sapling_notes(
WHERE account = :account
AND spent IS NULL
AND transactions.block <= :anchor_height
AND id_note NOT IN rarray(:exclude)",
AND id_note NOT IN rarray(:exclude)
AND NOT EXISTS (
SELECT 1 FROM v_sapling_shard_unscanned_ranges unscanned
-- select all the unscanned ranges involving the shard containing this note
WHERE sapling_received_notes.commitment_tree_position >= unscanned.start_position
AND sapling_received_notes.commitment_tree_position < unscanned.end_position_exclusive
-- exclude unscanned ranges above the anchor height which don't affect spendability
AND unscanned.block_range_start <= :anchor_height
)",
)?;
let excluded: Vec<Value> = exclude.iter().map(|n| Value::from(n.0)).collect();
@ -165,9 +173,7 @@ pub(crate) fn select_spendable_sapling_notes(
exclude: &[ReceivedNoteId],
) -> Result<Vec<ReceivedSaplingNote<ReceivedNoteId>>, SqliteClientError> {
// The goal of this SQL statement is to select the oldest notes until the required
// value has been reached, and then fetch the witnesses at the desired height for the
// selected notes. This is achieved in several steps:
//
// value has been reached.
// 1) Use a window function to create a view of all notes, ordered from oldest to
// newest, with an additional column containing a running sum:
// - Unspent notes accumulate the values of all unspent notes in that note's
@ -188,11 +194,20 @@ pub(crate) fn select_spendable_sapling_notes(
SUM(value)
OVER (PARTITION BY account, spent ORDER BY id_note) AS so_far
FROM sapling_received_notes
INNER JOIN transactions ON transactions.id_tx = sapling_received_notes.tx
INNER JOIN transactions
ON transactions.id_tx = sapling_received_notes.tx
WHERE account = :account
AND spent IS NULL
AND transactions.block <= :anchor_height
AND id_note NOT IN rarray(:exclude)
AND NOT EXISTS (
SELECT 1 FROM v_sapling_shard_unscanned_ranges unscanned
-- select all the unscanned ranges involving the shard containing this note
WHERE sapling_received_notes.commitment_tree_position >= unscanned.start_position
AND sapling_received_notes.commitment_tree_position < unscanned.end_position_exclusive
-- exclude unscanned ranges above the anchor height which don't affect spendability
AND unscanned.block_range_start <= :anchor_height
)
)
SELECT id_note, diversifier, value, rcm, commitment_tree_position
FROM eligible WHERE so_far < :target_value
@ -370,7 +385,7 @@ pub(crate) mod tests {
block::BlockHash,
consensus::BranchId,
legacy::TransparentAddress,
memo::Memo,
memo::{Memo, MemoBytes},
sapling::{
note_encryption::try_sapling_output_recovery, prover::TxProver, Note, PaymentAddress,
},
@ -418,10 +433,7 @@ pub(crate) mod tests {
zcash_client_backend::{
data_api::wallet::shield_transparent_funds, wallet::WalletTransparentOutput,
},
zcash_primitives::{
memo::MemoBytes,
transaction::components::{amount::NonNegativeAmount, OutPoint, TxOut},
},
zcash_primitives::transaction::components::{amount::NonNegativeAmount, OutPoint, TxOut},
};
pub(crate) fn test_prover() -> impl TxProver {
@ -555,8 +567,8 @@ pub(crate) mod tests {
let mut stmt_sent_notes = db_data
.conn
.prepare(
"SELECT output_index
FROM sent_notes
"SELECT output_index
FROM sent_notes
JOIN transactions ON transactions.id_tx = sent_notes.tx
WHERE transactions.txid = ?",
)