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Posted to commits@calcite.apache.org by GitBox <gi...@apache.org> on 2022/04/21 00:34:58 UTC
[GitHub] [calcite] JiajunBernoulli opened a new pull request, #2774: [CALCITE-5091] RelMdRowCount can return more accurate rowCount
JiajunBernoulli opened a new pull request, #2774:
URL: https://github.com/apache/calcite/pull/2774
Here is the sql that fetch is deterministic and offset is dynamic
`select * from emp order by ename limit 1 offset ?`
**RelMdRowCount#getRowCount** will return 14d, because it always return rowCount when offset is dynamic.
```
if (rel.offset instanceof RexDynamicParam) {
return rowCount;
}
```
Obviously, rowCount will not exceed 1 because LIMIT 1. We can improve it
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[GitHub] [calcite] JiajunBernoulli commented on a diff in pull request #2774: [CALCITE-5091] RelMdRowCount can return more accurate rowCount
Posted by GitBox <gi...@apache.org>.
JiajunBernoulli commented on code in PR #2774:
URL: https://github.com/apache/calcite/pull/2774#discussion_r855679082
##########
core/src/main/java/org/apache/calcite/rel/metadata/RelMdRowCount.java:
##########
@@ -147,45 +146,27 @@ public Double getRowCount(Calc rel, RelMetadataQuery mq) {
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
- if (rel.fetch != null) {
- if (rel.fetch instanceof RexDynamicParam) {
- return rowCount;
- }
- final int limit = RexLiteral.intValue(rel.fetch);
- if (limit < rowCount) {
- return (double) limit;
- }
- }
- return rowCount;
+ final double limit =
+ rel.fetch instanceof RexLiteral ? RexLiteral.intValue(rel.fetch) : rowCount;
+ return limit < rowCount ? limit : rowCount;
}
public @Nullable Double getRowCount(EnumerableLimit rel, RelMetadataQuery mq) {
Double rowCount = mq.getRowCount(rel.getInput());
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
Review Comment:
Yes, I think the row count value will be wrong.
Do you think **14d** is right for the sql?
`select * from emp order by ename limit 1 offset ?`
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[GitHub] [calcite] NobiGo commented on a diff in pull request #2774: [CALCITE-5091] RelMdRowCount can return more accurate rowCount
Posted by GitBox <gi...@apache.org>.
NobiGo commented on code in PR #2774:
URL: https://github.com/apache/calcite/pull/2774#discussion_r854954008
##########
core/src/main/java/org/apache/calcite/rel/metadata/RelMdRowCount.java:
##########
@@ -147,45 +146,27 @@ public Double getRowCount(Calc rel, RelMetadataQuery mq) {
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
- if (rel.fetch != null) {
- if (rel.fetch instanceof RexDynamicParam) {
- return rowCount;
- }
- final int limit = RexLiteral.intValue(rel.fetch);
- if (limit < rowCount) {
- return (double) limit;
- }
- }
- return rowCount;
+ final double limit =
+ rel.fetch instanceof RexLiteral ? RexLiteral.intValue(rel.fetch) : rowCount;
+ return limit < rowCount ? limit : rowCount;
}
public @Nullable Double getRowCount(EnumerableLimit rel, RelMetadataQuery mq) {
Double rowCount = mq.getRowCount(rel.getInput());
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
Review Comment:
If we don't care about the offset value when it is a dynamic param, the row count value will be wrong? I think the origin logic is good.
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[GitHub] [calcite] chunweilei merged pull request #2774: [CALCITE-5091] RelMdRowCount can return more accurate rowCount
Posted by GitBox <gi...@apache.org>.
chunweilei merged PR #2774:
URL: https://github.com/apache/calcite/pull/2774
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[GitHub] [calcite] NobiGo commented on a diff in pull request #2774: [CALCITE-5091] RelMdRowCount can return more accurate rowCount
Posted by GitBox <gi...@apache.org>.
NobiGo commented on code in PR #2774:
URL: https://github.com/apache/calcite/pull/2774#discussion_r855799246
##########
core/src/main/java/org/apache/calcite/rel/metadata/RelMdRowCount.java:
##########
@@ -147,45 +146,27 @@ public Double getRowCount(Calc rel, RelMetadataQuery mq) {
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
- if (rel.fetch != null) {
- if (rel.fetch instanceof RexDynamicParam) {
- return rowCount;
- }
- final int limit = RexLiteral.intValue(rel.fetch);
- if (limit < rowCount) {
- return (double) limit;
- }
- }
- return rowCount;
+ final double limit =
+ rel.fetch instanceof RexLiteral ? RexLiteral.intValue(rel.fetch) : rowCount;
+ return limit < rowCount ? limit : rowCount;
}
public @Nullable Double getRowCount(EnumerableLimit rel, RelMetadataQuery mq) {
Double rowCount = mq.getRowCount(rel.getInput());
if (rowCount == null) {
return null;
}
- if (rel.offset instanceof RexDynamicParam) {
- return rowCount;
- }
- final int offset = rel.offset == null ? 0 : RexLiteral.intValue(rel.offset);
+
+ final int offset = rel.offset instanceof RexLiteral ? RexLiteral.intValue(rel.offset) : 0;
rowCount = Math.max(rowCount - offset, 0D);
Review Comment:
The limit number is the max row count that the SQL can return.
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