getSwaps() returnAmount mismatch with on-chain result about balancer-sor HOT 5 CLOSED

Hi. Thanks for the info.
I think this may be related to using an outdated priceRate value but we would have to debug further. In the meantime maybe you could use queryBatchSwap with the swap info to get the accurate onchain value.

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Thanks for your suggrestion. I've tried with queryBatchSwap function. It halved the number of errored pools, but still receiving errors. My implementation is following :

`const swaps: BatchSwapStep[] = [
{
poolId: poolInfo.id,
assetInIndex: 0,
assetOutIndex: 1,
amount: amount0In.toString(),
userData: "0x",
},
];

const assets: string[] = [token0, token1];
const swapInfoTest = await balancer.swaps.queryBatchSwap({
kind: swapType,
swaps,
assets,
});`

The token0 and token1 are representing each token's address, and the swapType was set to SwapExactIn. What could be causing this errors? The difference between actual amount returned and queryBatchSwap results are usually less than 0.1%. I will attach the pools with the error.
batchswapError.json.zip

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I've been studying your file batchswapError.json and could replicate the reported behaviour for some of the pools.
Those with error code BAL#304, are simply due to not enough liquidity in those pools for the requested amount.
Regarding those with different outcomes, I wonder if it is possible that they are due to the time delay between the SOR query and batchSwap query. Most of the reported pools have parameters that change very rapidly, like price rates or moving weights.
Are we sure that both queries were performed with data from the same block?
For most of the reported errors, I think it's possible that the cause is different input data.

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Hi @sergioyuhjtman @johngrantuk , Thanks for the reply.

To clarify the batchswapError.json was comparison results between queryBatchSwap() and swap(). About the time delay between the queryBatchSwap() and Swap(), I fork at block#16217540 , then execute queryBatchSwap() at 16217540 and swap() at 16217541 respectively. However, I found queryBatchSwap is callstatic function which means it won't affect on the state to calculate the price calculation parameters. So that I don't think it is the problem related to time/block difference.

I will add the difference error between getSwap() from SOR and swap() form contract as well. The forked block number is 16217628.

Thank you in advance.

errors.zip

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Issue is resolved from 4.1.1 update

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