sql: change multi-row bounded staleness errors to reference rows, not ranges#71473
sql: change multi-row bounded staleness errors to reference rows, not ranges#71473nvb wants to merge 1 commit intocockroachdb:masterfrom
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… ranges The number of ranges is an implementation detail. The condition for bounded staleness reads to be accepted in v21.2 is that they touch up to a single row.
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This change is |
| # there's no guarantee of that - we could have empty ranges. | ||
| statement error unimplemented: cannot use bounded staleness for queries that may touch more than one range or require an index join | ||
| statement error unimplemented: cannot use bounded staleness for queries that may touch more than one row or require an index join | ||
| SELECT * FROM t AS OF SYSTEM TIME with_max_staleness('1ms') WHERE k IS NULL LIMIT 1 |
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This may be a case where the change is making things more confusing, instead of less. I can imagine users saying "I have a limit 1, so why isn't this working?". Does that seem like a concern to others as well? cc. @rmloveland @rytaft.
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I thought about this a little when first seeing this error too. It seems difficult to explain briefly in a SQL error message that using LIMIT still means multiple rows are being touched and then filtered down to the limit count, but I can try to address from the docs side by updating cockroachdb/docs#11896 to make clear that LIMIT still means more rows are being touched
We have some other error messages that link to docs using our internal link shortener, perhaps that could be useful here as well. The link would be: https://www.cockroachlabs.com/docs/stable/follower-reads.html
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Also filed cockroachdb/docs#11953 to address this possible misconception in our docs in a more general way (update LIMIT docs, various perf pages etc)
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Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status:complete! 0 of 0 LGTMs obtained (waiting on @nvanbenschoten)
pkg/ccl/logictestccl/testdata/logic_test/as_of, line 223 at r1 (raw file):
Previously, rmloveland (Rich Loveland) wrote…
Also filed cockroachdb/docs#11953 to address this possible misconception in our docs in a more general way (update
LIMITdocs, various perf pages etc)
Yea, this is the reason I used the word "range" instead of "row". But linking to the docs seems like a good solution.
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The number of ranges is an implementation detail. The condition for
bounded staleness reads to be accepted in v21.2 is that they touch up
to a single row.
Suggested by @rmloveland in cockroachdb/docs#11896.