Book totals

A generator inserts, updates and deletes positions, opens new books and closes older ones. Pgderive maintains the totals in Postgres. Supabase Realtime sends the changes to this page. The table shows the latest 100 books.

Positions (shown books)

Rows in the table below

Net units (shown books)

SUM(quantity), ignoring NULLs

Gross units (shown books)

Sum of absolute book totals

Browser events

Events received in this tab

Source row operations

INSERT + UPDATE + DELETE since stats reset

Generator commits observed

Measured every 15 seconds

R2 state size

Physical objects, sampled every minute

Worker memory

Process RSS, including caches and memtables

Write to sink latency (p50)

Oldest complete transaction in each epoch

Engine receipt through durable sink commit

Engine processing (p50)

Compute and sink commit

Excludes CDC wait and browser delivery

Source commit to sink (p50)

Source commit acknowledgement through sink progress

Independent observer; 50 ms polling

Loading engine measurements...

Loading totals across all books...

Book overview

ACTIVE BOOKS

Book	Positions	Net units	Weight¹
Connecting to the maintained table…

Net units of shown books

THIS TAB

RECENT SNAPSHOTSNOW

Result activity

LIVE CHANGEFEED

Waiting for committed result changes…

SQL

The maintained query

The result is a regular Postgres table. Book totals are computed by Pgderive. The chart and portfolio summary are calculated in this browser. Engine measurements come from the server.

SELECT book_id,
       COUNT(*) AS positions,
       SUM(quantity) AS units
FROM public.demo_positions
GROUP BY book_id;