status-go/services/wallet/transfer/iterative.go

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package transfer
import (
"context"
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"errors"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
)
// SetupIterativeDownloader configures IterativeDownloader with last known synced block.
func SetupIterativeDownloader(
client HeaderReader, address common.Address,
downloader BatchDownloader, size *big.Int, to *big.Int, from *big.Int) (*IterativeDownloader, error) {
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if to == nil || from == nil {
return nil, errors.New("to or from cannot be nil")
}
log.Debug("iterative downloader", "address", address, "from", from, "to", to, "size", size)
d := &IterativeDownloader{
client: client,
batchSize: size,
downloader: downloader,
from: from,
to: to,
}
return d, nil
}
// BatchDownloader interface for loading transfers in batches in speificed range of blocks.
type BatchDownloader interface {
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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GetHeadersInRange(ctx context.Context, from, to *big.Int) ([]*DBHeader, error)
}
// IterativeDownloader downloads batches of transfers in a specified size.
type IterativeDownloader struct {
client HeaderReader
batchSize *big.Int
downloader BatchDownloader
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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from, to *big.Int
previous *big.Int
}
// Finished true when earliest block with given sync option is zero.
func (d *IterativeDownloader) Finished() bool {
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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return d.from.Cmp(d.to) == 0
}
// Header return last synced header.
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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func (d *IterativeDownloader) Header() *big.Int {
return d.previous
}
// Next moves closer to the end on every new iteration.
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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func (d *IterativeDownloader) Next(parent context.Context) ([]*DBHeader, *big.Int, *big.Int, error) {
to := d.to
from := new(big.Int).Sub(to, d.batchSize)
// if start < 0; start = 0
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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if from.Cmp(d.from) == -1 {
from = d.from
}
headers, err := d.downloader.GetHeadersInRange(parent, from, to)
log.Debug("load erc20 transfers in range", "from", from, "to", to, "batchSize", d.batchSize)
if err != nil {
log.Error("failed to get transfer in between two blocks", "from", from, "to", to, "error", err)
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
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return nil, nil, nil, err
}
status-im/status-react#9203 Faster tx fetching with less request *** How it worked before this PR on multiaccount creation: - On multiacc creation we scanned chain for eth and erc20 transfers. For each address of a new empty multiaccount this scan required 1. two `eth_getBalance` requests to find out that there is no any balance change between zero and the last block, for eth transfers 2. and `chain-size/100000` (currently ~100) `eth_getLogs` requests, for erc20 transfers - For some reason we scanned an address of the chat account as well, and also accounts were not deduplicated. So even for an empty multiacc we scanned chain twice for each chat and main wallet addresses, in result app had to execute about 400 requests. - As mentioned above, `eth_getBalance` requests were used to check if there were any eth transfers, and that caused empty history in case if user already used all available eth (so that both zero and latest blocks show 0 eth for an address). There might have been transactions but we wouldn't fetch/show them. - There was no upper limit for the number of rpc requests during the scan, so it could require indefinite number of requests; the scanning algorithm was written so that we persisted the whole history of transactions or tried to scan form the beginning again in case of failure, giving up only after 10 minutes of failures. In result addresses with sufficient number of transactions would never be fully scanned and during these 10 minutes app could use gigabytes of internet data. - Failures were caused by `eth_getBlockByNumber`/`eth_getBlockByHash` requests. These requests return significantly bigger responses than `eth_getBalance`/`eth_transactionsCount` and it is likely that execution of thousands of them in parallel caused failures for accounts with hundreds of transactions. Even for an account with 12k we could successfully determine blocks with transaction in a few minutes using `eth_getBalance` requests, but `eth_getBlock...` couldn't be processed for this acc. - There was no caching for for `eth_getBalance` requests, and this caused in average 3-4 times more such requests than is needed. *** How it works now on multiaccount creation: - On multiacc creation we scan chain for last ~30 eth transactions and then check erc20 in the range where these eth transactions were found. For an empty address in multiacc this means: 1. two `eth_getBalance` transactions to determine that there was no balance change between zero and the last block; two `eth_transactionsCount` requests to determine there are no outgoing transactions for this address; total 4 requests for eth transfers 2. 20 `eth_getLogs` for erc20 transfers. This number can be lowered, but that's not a big deal - Deduplication of addresses is added and also we don't scan chat account, so a new multiacc requires ~25 (we also request latest block number and probably execute a few other calls) request to determine that multiacc is empty (comparing to ~400 before) - In case if address contains transactions we: 1. determine the range which contains 20-25 outgoing eth/erc20 transactions. This usually requires up to 10 `eth_transactionCount` requests 2. then we scan chain for eth transfers using `eth_getBalance` and `eth_transactionCount` (for double checking zero balances) 3. we make sure that we do not scan db for more than 30 blocks with transfers. That's important for accounts with mostly incoming transactions, because the range found on the first step might contain any number of incoming transfers, but only 20-25 outgoing transactions 4. when we found ~30 blocks in a given range, we update initial range `from` block using the oldest found block 5. and now we scan db for erc20transfers using `eth_getLogs` `oldest-found-eth-block`-`latest-block`, we make not more than 20 calls 6. when all blocks which contain incoming/outgoing transfers for a given address are found, we save these blocks to db and mark that transfers from these blocks are still to be fetched 7. Then we select latest ~30 (the number can be adjusted) blocks from these which were found and fetch transfers, this requires 3-4 requests per transfer. 8. we persist scanned range so that we know were to start next time 9. we dispatch an event which tells client that transactions are found 10. client fetches latest 20 transfers - when user presses "fetch more" button we check if app's db contains next 20 transfers, if not we scan chain again and return transfers after small fixes
2019-12-18 11:01:46 +00:00
d.previous, d.to = d.to, from
return headers, d.from, to, nil
}
// Revert reverts last step progress. Should be used if application failed to process transfers.
// For example failed to persist them.
func (d *IterativeDownloader) Revert() {
if d.previous != nil {
d.from = d.previous
}
}