postgres.git / summary / log / commit / refs

commit    fbd4321fd5b4400fbbf356d686af6ad6d3208c66
Author:   Alexander Korotkov <akorotkov@postgresql.org>
Date:     Wed May 22 23:22:40 2024 +0000
First released in: 17.0

    Don't copy extended statistics during MERGE/SPLIT partition operations
    
    When MERGE/SPLIT created new partitions, it was cloning the extended
    statistics of the parent table.
    
    However, extended stats on partitioned tables don't behave like
    indexes on partitioned tables (which exist only to create physical
    indexes on child tables).  Rather, extended stats on a parent 1) cause
    extended stats to be collected and computed across the whole partition
    hierarchy, and 2) do not cause extended stats to be computed for the
    individual partitions.
    
    "CREATE TABLE ... PARTITION OF" command doesn't copy extended
    statistics.  This commit makes createPartitionTable() behave
    consistently.
    
    Reported-by: Justin Pryzby
    Discussion: https://postgr.es/m/ZiJW1g2nbQs9ekwK%40pryzbyj2023
    Author: Alexander Korotkov, Justin Pryzby


 doc/src/sgml/ref/alter_table.sgml | 9 +++++++--
 src/backend/commands/tablecmds.c  | 8 +++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 5d352abf991..c062a36880d 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -1154,9 +1154,12 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
      <para>
       The new partitions will be created the same as tables created with the
-      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_nameN</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY)</literal>.
+      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_nameN</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY EXCLUDING STATISTICS)</literal>.
       The indexes and identity are created later, after moving the data
       into the new partitions.
+      Extended statistics aren't copied from the parent table, for consistency with
+      <command>CREATE TABLE PARTITION OF</command>.
+
       New partitions will have the same table access method as the parent.
       If the parent table is persistent then new partitions are created
       persistent.  If the parent table is temporary then new partitions
@@ -1224,9 +1227,11 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
      <para>
       The new partition will be created the same as a table created with the
-      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_name</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY)</literal>.
+      SQL command <literal>CREATE TABLE <replaceable class="parameter">partition_name</replaceable> (LIKE <replaceable class="parameter">name</replaceable> INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY EXCLUDING STATISTICS)</literal>.
       The indexes and identity are created later, after moving the data
       into the new partition.
+      Extended statistics aren't copied from the parent table, for consistency with
+      <command>CREATE TABLE PARTITION OF</command>.
       The new partition will have the same table access method as the parent.
       If the parent table is persistent then the new partition is created
       persistent.  If the parent table is temporary then the new partition
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7a063ca8ae0..7b6c69b7a52 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -20269,7 +20269,7 @@ moveSplitTableRows(Relation rel, Relation splitRel, List *partlist, List *newPar
  * (newPartName) like table (modelRel)
  *
  * Emulates command: CREATE [TEMP] TABLE <newPartName> (LIKE <modelRel's name>
- * INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY)
+ * INCLUDING ALL EXCLUDING INDEXES EXCLUDING IDENTITY EXCLUDING STATISTICS)
  *
  * Also, this function sets the new partition access method same as parent
  * table access methods (similarly to CREATE TABLE ... PARTITION OF).  It
@@ -20313,9 +20313,11 @@ createPartitionTable(RangeVar *newPartName, Relation modelRel,
 
 	/*
 	 * Indexes will be inherited on "attach new partitions" stage, after data
-	 * moving.
+	 * moving.  We also don't copy the extended statistics for consistency
+	 * with CREATE TABLE PARTITION OF.
 	 */
-	tlc->options = CREATE_TABLE_LIKE_ALL & ~(CREATE_TABLE_LIKE_INDEXES | CREATE_TABLE_LIKE_IDENTITY);
+	tlc->options = CREATE_TABLE_LIKE_ALL &
+		~(CREATE_TABLE_LIKE_INDEXES | CREATE_TABLE_LIKE_IDENTITY | CREATE_TABLE_LIKE_STATISTICS);
 	tlc->relationOid = InvalidOid;
 	createStmt->tableElts = lappend(createStmt->tableElts, tlc);
 


[parent: 3a82c689fd1b]