Fix stale comment about sample_frac adjustment

tvondra · tvondra · commit 211d80c06562 · 2023-01-06T14:47:23.000+01:00
A comment was left behind referencing sample rate adjustment removed from 8ad51b5. So clean that up. While at it also remove the sample rate clamping which should not be necessary without the clamping, and just check that with an assert. Reported-by: Tom Lane Discussion: https://postgr.es/m/951485.1672461744%40sss.pgh.pa.us
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
@@ -5204,10 +5204,11 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
 			sample_frac = targrows / reltuples;
 
 			/*
-			 * Ensure the sampling rate is between 0.0 and 1.0, even after the
-			 * 10% adjustment above.  (Clamping to 0.0 is just paranoia.)
+			 * We should never get sampling rate outside the valid range
+			 * (between 0.0 and 1.0), because those cases should be covered
+			 * by the previous branch that sets ANALYZE_SAMPLE_OFF.
 			 */
-			sample_frac = Min(1.0, Max(0.0, sample_frac));
+			Assert(sample_frac >= 0.0 && sample_frac <= 1.0);
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -5204,10 +5204,11 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,`
`5204`	`5204`	`sample_frac = targrows / reltuples;`
`5205`	`5205`
`5206`	`5206`	`/*`
`5207`		`- * Ensure the sampling rate is between 0.0 and 1.0, even after the`
`5208`		`- * 10% adjustment above. (Clamping to 0.0 is just paranoia.)`
	`5207`	`+ * We should never get sampling rate outside the valid range`
	`5208`	`+ * (between 0.0 and 1.0), because those cases should be covered`
	`5209`	`+ * by the previous branch that sets ANALYZE_SAMPLE_OFF.`
`5209`	`5210`	`*/`
`5210`		`- sample_frac = Min(1.0, Max(0.0, sample_frac));`
	`5211`	`+ Assert(sample_frac >= 0.0 && sample_frac <= 1.0);`
`5211`	`5212`	`}`
`5212`	`5213`	`}`
`5213`	`5214`