Simplify IS NULL and IS NOT NULL expressions. #2662
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| @@ -508,7 +545,7 @@ func TestSimplifyOrExprCheck(t *testing.T) { | |||
| {`a = 1 OR a = 1`, `a = 1`}, | |||
| {`a = 1 OR a = 2`, `a IN (1, 2)`}, | |||
| {`a = 2 OR a = 1`, `a IN (1, 2)`}, | |||
| {`a = 1 OR a != 1`, `true`}, | |||
| {`a = 1 OR a != 1`, `a IS NOT NULL`}, | |||
There was a problem hiding this comment.
Simplifying a = 1 OR a != 1 to true was a bug. Those expressions are not equivalent if a is NULL. This was caught be the enhancements to checkEquivExpr to test the NULL value in the expressions. Yay tests!
|
LGTM |
Use "a != <val>" and "a IS NOT NULL" expressions to restrict the start of scan ranges to not include NULL values. Use "a IS NULL" expressions to restrict the end range to stop at the end of the NULL values. The code is thorny. I recommend concentrating on the test cases. See #2636.
petermattis
force-pushed
the
pmattis/sql-analyze-is-not-null
branch
from
30632b8 to
0da471f
Compare
|
LGTM |
petermattis
added a commit
that referenced
this pull request
Sep 25, 2015
…null Simplify IS NULL and IS NOT NULL expressions.
RaduBerinde
added a commit
to RaduBerinde/cockroach
that referenced
this pull request
Jun 30, 2023
…598cb059 c0a2ede2 db: improve delete pacing (cockroachdb/pebble#2696) Informs cockroachdb#2662. Release justification: fixes very high goroutine count on heavy write workloads with fast disks. Release note (bug fix): On heavy write workloads with fast disks, the deletion of obsolete LSM files could fall behind, causing high goroutine count. Pacing of obsolete file deletion now adapts based on recent deletion rate to avoid falling behind.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Use "a != " and "a IS NOT NULL" expressions to restrict the start
of scan ranges to not include NULL values. Use "a IS NULL" expressions
to restrict the end range to stop at the end of the NULL values.
The code is thorny. I recommend concentrating on the test cases.
See #2636.