Asset holders query

[charlie-wasp]

Here's asset holders query implementation. It somewhat depends on #154 in technical details regarding pagination, but all necessary parts are duplicated, so this PR can be merged first

We may want to add index on assetcode + issuer fields in trustlines table to speed things up

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This change is 

[nebolsin]

Reviewed 12 of 12 files at r1.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @charlie-wasp)

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src/repo/assets.ts, line 68 at r1 (raw file):

      if (paging.after) {
        queryBuilder.where("balance < ?", balance);

We should use <= balance/>= balance and also introduce strict condition on accountid from the cursor. Currently the pagination will stop as soon as you reach a first zero-balance account, because the next page request will result in where balance < 0.

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src/schema/assets.ts, line 18 at r1 (raw file):

    code: AssetCode!
    "All accounts that trust this asset, ordered by balance"
    holders(first: Int, last: Int, after: String, before: String): BalanceConnection

Let's call it balances for better consistency with the result data type and Account side.

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src/schema/assets.ts, line 36 at r1 (raw file):

    flags: AccountFlags
    "All accounts that trust this asset, ordered by balance"
    holders(first: Int, last: Int, after: String, before: String): BalanceConnection

I'm not sure we need to introduce holders to both Asset and AssetWithInfo. And by the way, do we still need those two separate types? Looks like the Asset type and AssetID scalar provide exactly the same information.

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src/util/paging.ts, line 31 at r1 (raw file):

export function properlyOrdered(records: any[], pagingParams: PagingParams): any[] {
  if (pagingParams.last && pagingParams.before) {

Hmm, I believe that presence of before param should not affect our ordering in any way, should it?

[charlie-wasp]

Reviewable status: 9 of 12 files reviewed, 4 unresolved discussions (waiting on @nebolsin)

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src/repo/assets.ts, line 68 at r1 (raw file):

Previously, nebolsin (Sergey Nebolsin) wrote…

We should use <= balance/>= balance and also introduce strict condition on accountid from the cursor. Currently the pagination will stop as soon as you reach a first zero-balance account, because the next page request will result in where balance < 0.

Done.

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src/schema/assets.ts, line 18 at r1 (raw file):

Previously, nebolsin (Sergey Nebolsin) wrote…

Let's call it balances for better consistency with the result data type and Account side.

Done.

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src/schema/assets.ts, line 36 at r1 (raw file):

Previously, nebolsin (Sergey Nebolsin) wrote…

I'm not sure we need to introduce holders to both Asset and AssetWithInfo. And by the way, do we still need those two separate types? Looks like the Asset type and AssetID scalar provide exactly the same information.

Well, AssetWithInfo is the type for a data, which Horizon returns. It contains additional amount and numAccounts fields. We would be able to reduce them to the single type, when we'll fetch assets from core database.

If we don't want to get a list of assets with corresponding holders, we can drop holders from here

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src/util/paging.ts, line 31 at r1 (raw file):

Previously, nebolsin (Sergey Nebolsin) wrote…

Hmm, I believe that presence of before param should not affect our ordering in any way, should it?

Oh my god, this pagination discussion seems to be infinite 😅 Give me a sec... We need to reverse records on backward motion, because we call invertSortOrder, if before is set (look at parseCursorPagination method above). Quite opaque and convoluted logic 😔

[nebolsin]

Reviewed 2 of 3 files at r2, 2 of 3 files at r3, 1 of 1 files at r4.
Reviewable status: complete! all files reviewed, all discussions resolved