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Fix wording to reflect poor performance of initial query before optimization #20840

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Fix wording to reflect poor performance of initial query before optimization #20840

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2 changes: 1 addition & 1 deletion explain-walkthrough.md
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Expand Up @@ -73,7 +73,7 @@ EXPLAIN ANALYZE SELECT count(*) FROM trips WHERE start_date BETWEEN '2017-07-01
5 rows in set (1.03 sec)
```

The example query above takes `1.03` seconds to execute, which is an ideal performance.
The example query above takes `1.03` seconds to execute, which is not ideal performance.

From the result of `EXPLAIN ANALYZE` above, `actRows` indicates that some of the estimates (`estRows`) are inaccurate (expecting 10 thousand rows but finding 19 million rows), which is already indicated in the `operator info` (`stats:pseudo`) of `└─TableFullScan_18`. If you run [`ANALYZE TABLE`](/sql-statements/sql-statement-analyze-table.md) first and then `EXPLAIN ANALYZE` again, you can see that the estimates are much closer:

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