[doris] 01/04: [improvement](query)optimize select stmt with limit 0 (#14956)

[morningman]

This is an automated email from the ASF dual-hosted git repository.

morningman pushed a commit to branch branch-1.2-lts
in repository https://gitbox.apache.org/repos/asf/doris.git

commit ca97e49b7d3b785e290173ec59ebed43a57d870b
Author: chenlinzhong <490103...@qq.com>
AuthorDate: Wed Dec 14 13:48:09 2022 +0800

    [improvement](query)optimize select stmt with limit 0  (#14956)
---
 .../src/main/java/org/apache/doris/qe/StmtExecutor.java      | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java 
b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
index 8feaaa3e6f..6b1041373d 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
@@ -1105,6 +1105,18 @@ public class StmtExecutor implements ProfileWriter {
             handleCacheStmt(cacheAnalyzer, channel, (SelectStmt) queryStmt);
             return;
         }
+
+        // handle select .. from xx  limit 0
+        if (parsedStmt instanceof SelectStmt) {
+            SelectStmt parsedSelectStmt = (SelectStmt) parsedStmt;
+            if (parsedSelectStmt.getLimit() == 0) {
+                LOG.info("ignore handle limit 0 ,sql:{}", 
parsedSelectStmt.toSql());
+                sendFields(queryStmt.getColLabels(), 
exprToType(queryStmt.getResultExprs()));
+                context.getState().setEof();
+                return;
+            }
+        }
+
         sendResult(isOutfileQuery, false, queryStmt, channel, null, null);
     }
 


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