The candle still paused for ten to twenty seconds at a time. Instrumenting the
raw Level 1 stream settled why: 87 messages in 90 seconds, only 33 carrying
LAST_PRICE. Most of the remainder is bid and ask movement, correctly ignored,
but a seventh carry LAST_SIZE, TRADE_TIME_MILLIS and TOTAL_VOLUME with no
LAST_PRICE — trades that printed at the price of the one before, so the field
did not change and Level 1 did not resend it.
Requiring LAST_PRICE discarded those trades and their volume with them.
parse_level_one now recognises size-plus-trade-time as a trade and returns a
null price, which stream() fills from the forming bar. A quote carrying neither
a price nor any trade field is still skipped: a bid is not a trade and must not
extend a candle's high or low.
Measured on the live feed: median gap between updates 3.1s to 2.0s, worst gap
21.5s to 8.1s, roughly 9 updates a minute to 22, and bar volume climbs within
the minute instead of standing still.
The pauses that remain are the market rather than the pipe. Thin pre-open tape
goes seconds without a price-changing trade and then moves several ticks at
once, which is what a gap up after a quiet spell is.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Chris Amow
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