accelerate dumpTree by cache tree_id inside BlockInputStream and repl…

…ace stringstream by FmtBuffer (#4506) close #4494
pingcap · Mar 31, 2022 · 4afdc08 · 4afdc08
1 parent cf792d1
commit 4afdc08
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Showing 3 changed files with 37 additions and 25 deletions.
diff --git a/dbms/src/DataStreams/IBlockInputStream.cpp b/dbms/src/DataStreams/IBlockInputStream.cpp
@@ -30,22 +30,26 @@ extern const int TOO_DEEP_PIPELINE;
 
 String IBlockInputStream::getTreeID() const
 {
-    std::stringstream s;
-    s << getName();
-
-    if (!children.empty())
+    std::lock_guard lock(tree_id_mutex);
+    if (tree_id.empty())
     {
-        s << "(";
-        for (BlockInputStreams::const_iterator it = children.begin(); it != children.end(); ++it)
+        FmtBuffer buffer;
+        buffer.append(getName());
+
+        if (!children.empty())
         {
-            if (it != children.begin())
-                s << ", ";
-            s << (*it)->getTreeID();
+            buffer.append("(");
+            buffer.joinStr(
+                children.cbegin(),
+                children.cend(),
+                [](const auto & r, FmtBuffer & fb) { fb.append(r->getTreeID()); },
+                ", ");
+            buffer.append(")");
         }
-        s << ")";
+        tree_id = buffer.toString();
     }
 
-    return s.str();
+    return tree_id;
 }
 
 
@@ -60,7 +64,7 @@ size_t IBlockInputStream::checkDepthImpl(size_t max_depth, size_t level) const
         return 0;
 
     if (level > max_depth)
-        throw Exception("Query pipeline is too deep. Maximum: " + toString(max_depth), ErrorCodes::TOO_DEEP_PIPELINE);
+        throw Exception(fmt::format("Query pipeline is too deep. Maximum: {}", max_depth), ErrorCodes::TOO_DEEP_PIPELINE);
 
     size_t res = 0;
     for (const auto & child : children)
@@ -74,13 +78,14 @@ size_t IBlockInputStream::checkDepthImpl(size_t max_depth, size_t level) const
 }
 
 
-void IBlockInputStream::dumpTree(std::ostream & ostr, size_t indent, size_t multiplier)
+void IBlockInputStream::dumpTree(FmtBuffer & buffer, size_t indent, size_t multiplier)
 {
-    ostr << String(indent, ' ') << getName();
-    if (multiplier > 1)
-        ostr << " × " << multiplier;
-    //ostr << ": " << getHeader().dumpStructure();
-    ostr << std::endl;
+    // todo append getHeader().dumpStructure()
+    buffer.fmtAppend(
+        "{}{}{}\n",
+        String(indent, ' '),
+        getName(),
+        multiplier > 1 ? fmt::format(" x {}", multiplier) : "");
     ++indent;
 
     /// If the subtree is repeated several times, then we output it once with the multiplier.
@@ -96,7 +101,7 @@ void IBlockInputStream::dumpTree(std::ostream & ostr, size_t indent, size_t mult
         size_t & subtree_multiplier = multipliers[id];
         if (subtree_multiplier != 0) /// Already printed subtrees are marked with zero in the array of multipliers.
         {
-            child->dumpTree(ostr, indent, subtree_multiplier);
+            child->dumpTree(buffer, indent, subtree_multiplier);
             subtree_multiplier = 0;
         }
     }

diff --git a/dbms/src/DataStreams/IBlockInputStream.h b/dbms/src/DataStreams/IBlockInputStream.h
@@ -14,6 +14,7 @@
 
 #pragma once
 
+#include <Common/FmtUtils.h>
 #include <Core/Block.h>
 #include <Core/SortDescription.h>
 #include <Storages/TableLockHolder.h>
@@ -122,7 +123,7 @@ class IBlockInputStream : private boost::noncopyable
 
     /** Must be called before read, readPrefix.
       */
-    void dumpTree(std::ostream & ostr, size_t indent = 0, size_t multiplier = 1);
+    void dumpTree(FmtBuffer & buffer, size_t indent = 0, size_t multiplier = 1);
 
     /** Check the depth of the pipeline.
       * If max_depth is specified and the `depth` is greater - throw an exception.
@@ -184,8 +185,11 @@ class IBlockInputStream : private boost::noncopyable
     TableLockHolders table_locks;
 
     size_t checkDepthImpl(size_t max_depth, size_t level) const;
+    mutable std::mutex tree_id_mutex;
+    mutable String tree_id;
 
-    /// Get text with names of this source and the entire subtree.
+    /// Get text with names of this source and the entire subtree, this function should only be called after the
+    /// InputStream tree is constructed.
     String getTreeID() const;
 };
 

diff --git a/dbms/src/Interpreters/executeQuery.cpp b/dbms/src/Interpreters/executeQuery.cpp
@@ -386,10 +386,13 @@ std::tuple<ASTPtr, BlockIO> executeQueryImpl(
 
             if (!internal && res.in)
             {
-                std::stringstream log_str;
-                log_str << "Query pipeline:\n";
-                res.in->dumpTree(log_str);
-                LOG_DEBUG(execute_query_logger, log_str.str());
+                auto pipeline_log_str = [&res]() {
+                    FmtBuffer log_buffer;
+                    log_buffer.append("Query pipeline:\n");
+                    res.in->dumpTree(log_buffer);
+                    return log_buffer.toString();
+                };
+                LOG_DEBUG(execute_query_logger, pipeline_log_str());
             }
         }
     }