Get sync-to-marketstore-tsdb history retrieval workinnn

piker/data/feed.py

@@ -36,6 +36,7 @@ from trio.abc import ReceiveChannel
 from trio_typing import TaskStatus
 import tractor
 from pydantic import BaseModel
+import numpy as np
 
 from ..brokers import get_brokermod
 from .._cacheables import maybe_open_context
@@ -276,23 +277,13 @@ async def manage_history(
                 # TODO: this should be used verbatim for the pure
                 # shm backfiller approach below.
 
-                # start history anal and load missing new data via backend.
+                def diff_history(
-                async with open_history_client(fqsn) as hist:
+                    array,
+                    start_dt,
+                    end_dt,
 
-                    # get latest query's worth of history all the way
+                ) -> np.ndarray:
-                    # back to what is recorded in the tsdb
-                    array, start_dt, end_dt = await hist(end_dt='')
-                    shm.push(array)
 
-                    # let caller unblock and deliver latest history frame
-                    task_status.started(shm)
-                    some_data_ready.set()
-
-                    # pull new history frames until we hit latest
-                    # already in the tsdb
-                    while start_dt > last_tsdb_dt:
-
-                        array, start_dt, end_dt = await hist(end_dt=start_dt)
                     s_diff = (last_tsdb_dt - start_dt).seconds
 
                     # if we detect a partial frame's worth of data
@@ -305,19 +296,34 @@ async def manage_history(
                         log.info(
                             f'Pushing partial frame {to_push.size} to shm'
                         )
-                            shm.push(to_push, prepend=True)
+                        return to_push
-                            break
 
                     else:
-                            # write to shm
+                        return array
-                            log.info(f'Pushing {array.size} datums to shm')
+
-                            shm.push(array, prepend=True)
+                # start history anal and load missing new data via backend.
+                async with open_history_client(fqsn) as hist:
+
+                    # get latest query's worth of history all the way
+                    # back to what is recorded in the tsdb
+                    array, start_dt, end_dt = await hist(end_dt='')
+                    to_push = diff_history(array, start_dt, end_dt)
+                    shm.push(to_push)
+
+                    # let caller unblock and deliver latest history frame
+                    task_status.started(shm)
+                    some_data_ready.set()
+
+                    # pull new history frames until we hit latest
+                    # already in the tsdb
+                    while start_dt > last_tsdb_dt:
+                        array, start_dt, end_dt = await hist(end_dt=start_dt)
+                        to_push = diff_history(array, start_dt, end_dt)
+                        shm.push(to_push, prepend=True)
 
                     # TODO: see if there's faster multi-field reads:
                     # https://numpy.org/doc/stable/user/basics.rec.html#accessing-multiple-fields
                     # re-index  with a `time` and index field
-                    # await tractor.breakpoint()
-
                     shm.push(
                         fastest[-shm._first.value:],