> The pricing page/docs leaves so many questions unanswered:
The pricing page and docs make "rows" very clear. I was never referring to the blog post, nor was truetraveller.
> How are rows read and rows written calculated? > Every time a query retrieves a row from the database, it is counted as a row read. Every time a row is written to the database, it is counted as a row written.
From the billing docs:
> our paid Scaler plan comes with 25 GB storage, 100 billion row reads, and 50 million row writes
> Every row read from a table during execution adds to the rows read count, regardless of how many rows are returned.
> You can test a query for approximate rows read using the EXPLAIN statement. Running EXPLAIN with your query will return information about the query execution plan.
> To see the exact rows read, you will need to run the query. You can use the EXPLAIN ANALYZE statement to do this. It will return the estimated information about how it will run the query, run the query, and then return the actual impact from running the query.
> Another useful way to check rows read is using innodb_rows_read. This server status variable will show you the number of rows read across all tables. You can run it before and after queries to calculate how many rows were read.
These bits are extremely specific, down to the storage engine level. I don't know what more you could be looking for as to what "rows read" means than `innodb_rows_read`.
On the contrary, this is completely unclear because the mysql manual doesn't even give a clear explanation at all!! it only says "The number of rows read from InnoDB tables." https://dev.mysql.com/doc/refman/8.0/en/server-status-variab...
Let's say my db has a primary and 3 replicas. I insert one row. Does planetscale count this as 1 row written? 4 rows written?
Let's say my rows are small and there are 200 per DB page. I do a single-row select by primary key. This reads the page (you physically can't read just one "row" at the i/o level). Is this 1 row read or 200?
My read query triggers an internal temp table. Is the number of rows read based on only on the real tables, or also add in "reads" from the temp table? What if the temp table spills over to disk for a filesort?
I alter a table with 100 million rows. Is this 100 million rows read + 100 million rows written? or 0? something else? while this is happening, do my ongoing writes to the table count double for the shadow table?
Does planetscale even know the answers to these questions or are they just going by innodb status variables? do they actually have any innodb developers on staff or are they externalizing 100% of their actual "database" development to Oracle? (despite their blog post using wording like "we continue to build the best database on the planet"??)
