Why doesn't INDEX fragmentation change after REBUILD?

Question

SQL

There is a script for defragmentation of indexes

USE [Backup2];
GO

SET NOCOUNT ON;
DECLARE @objectid int;
DECLARE @indexid int;
DECLARE @partitioncount bigint;
DECLARE @schemaname nvarchar(130);
DECLARE @objectname nvarchar(130);
DECLARE @indexname nvarchar(130);
DECLARE @partitionnum bigint;
DECLARE @partitions bigint;
DECLARE @frag float;
DECLARE @command nvarchar(4000);
DECLARE @dbid smallint;

-- Выбираем индексы с уровнем фрагментации выше 10%
-- Определяем текущую БД

SET @dbid = DB_ID();
SELECT
     [object_id] AS objectid,
     index_id AS indexid,
     partition_number AS partitionnum,
     avg_fragmentation_in_percent AS frag, page_count
INTO #work_to_do
FROM sys.dm_db_index_physical_stats (@dbid, NULL, NULL , NULL, N'LIMITED')
WHERE avg_fragmentation_in_percent > 10.0
AND index_id > 0 -- игнорируем heap
AND page_count > 15 -- игнорируем маленькие таблицы
AND index_type_desc <> 'CLUSTERED INDEX'; --игнорируем кластерные индексы

-- объявляем курсор для списка обрабатываемых partition
DECLARE partitions CURSOR FOR SELECT objectid,indexid, partitionnum,frag
FROM #work_to_do;

OPEN partitions;

-- цикл по partition
WHILE (1=1)
BEGIN
FETCH NEXT
FROM partitions
INTO @objectid, @indexid, @partitionnum, @frag;
IF @@FETCH_STATUS < 0 BREAK;
SELECT @objectname = QUOTENAME(o.name), @schemaname = QUOTENAME(s.name)
FROM sys.objects AS o
JOIN sys.schemas AS s ON s.schema_id = o.schema_id
WHERE o.object_id = @objectid;

SELECT @indexname = QUOTENAME(name)
FROM sys.indexes
WHERE object_id = @objectid AND index_id = @indexid;
SELECT @partitioncount = count (*)
FROM sys.partitions
WHERE object_id = @objectid AND index_id = @indexid;

-- 30% считаем пределом для определения типа обновления индекса.
IF @frag < 30.0
     SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname
+ N'.' + @objectname + N' REORGANIZE';
IF @frag >= 30.0
     SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname
+ N'.' + @objectname + N' REBUILD WITH (ONLINE = ON)';
IF @partitioncount > 1
     SET @command = @command + N' PARTITION=' + CAST(@partitionnum AS
nvarchar(10));

EXEC (@command);
PRINT N'Выполнено: ' + @command;
END;

CLOSE partitions;
DEALLOCATE partitions;

-- удаляем временную таблицу
DROP TABLE #work_to_do;
GO

If, after execution, you run a query that outputs avg_fragmentation_in_percent, it will show exactly the same number of records and the same degree of fragmentation. Why?
P.S. The defragmentation script is taken from the terrasoft.ru blog and slightly modified

Answer 1

UPDATE STATISTICS?

Answer 2

You are right, statistics were updated only for indexes rebuilt by REBUILD, REORGANIZE remained the same. Thanks