Improve get_trade_history API performance

[abitmore]

The performance is terrible if start is too small.

[oxarbitrage]

yea, checked, really sucks. i think a binary search against the date like the one done here : https://github.com/bitshares/bitshares-core/pull/405/files?diff=unified can improve the call speed in all situations. let me know what do you think.

[oxarbitrage]

lets see if we can pass this first: #455 before sending code to the same call.

[abitmore]

Just noticed that bitshares-ui is not using this API. I'm not sure what application is using it. Since the pagination was largely broken (see #448), it's fair to guess that no application is relying on it. The get_ticker API was relying on it, but has been changed in #455.

I propose to change the behavior of this API to silently return an empty set if need to skip too many rows (E.G. 100) due to a too small start.

Thoughts?

[pmconrad]

Rename it to get_trade_history_deprecated and remove it after the next release. If anyone complains about the renaming we know they have been using it.

[abitmore]

Still need to use it to load the first page, so I don't want to deprecate it completely. See #448 .

[pmconrad]

Uh...

it's fair to guess that no application is relying on it.

Still need to use it to load the first page

Is is still in use or not?

[abitmore]

When I was saying "fair to guess that no application is relying on it", "it" means the pagination.

Rather than deprecating it, I would add an index (base + quote + time) so we can efficiently query with a time range.

[pmconrad]

Got it.

[abitmore]

I think this can be closed as well. Fixed in #478.