release-2.1: assorted CTE fixes #31051
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This commit introduces Cockroach-style single-use CTEs to the optimizer. Such CTEs cannot be referenced more than once in a query. Release note: None
These two checks are now exhaustive, meaning anything missing from them going forward is an error. Release note: None
The SQL standard (and pg) specifies that CTEs containing mutations are executed no matter how / how many times they are used in the remainder of the query. Meanwhile the heuristic planner + execution machinery is currently unable to force the execution of CTEs containing mutations if they are not otherwise used in the rest of the query. However meanwhile they are also accepted silently -- i.e. CockroachDB silently fails to do what the semantics require. This patch changes the behavior to instead report an error "feature not supported". Release note (bug fix): CockroachDB now reports an unimplemented error when a common table expression containing INSERT/UPDATE/UPSERT/DELETE is not otherwise used in the remainder of the query.
Prior to this patch, CockroachDB silently ignored WITH clauses within parentheses, so that the following SQL would return incorrect results: ``` CREATE TABLE t(x INT); (WITH t AS (SELECT 1) TABLE t); ``` (note: `WITH ...` *without* parentheses did work fine) This patch fixes this particular issue, and causes CockroachDB to issue an "unimplemented error" in other cases not supported yet, for example when there are multiple nested WITH clauses within parentheses. Release note (bug fix): CockroachDB does not silently ignore WITH clauses within parentheses any more.
Release note: None
Release note (sql change): CockroachDB now supports CTEs inside views.
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First 5 commits LGTM. I'll let someone review the last one who reviewed the original PR. |
jordanlewis
approved these changes
Oct 10, 2018
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Backport:
Please see individual PRs for details.
/cc @cockroachdb/release