Thank you a lot for your attention and reply .

But the cost of index seek for IX_Invoice is 1% and the logical reads for Invoice table is just 14286.

Table 'Transaction'. Scan count 919840, logical reads 3939737, physical reads 146, read-ahead reads 444, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

Table 'Invoice'. Scan count 1, logical reads 14286, physical reads 63, read-ahead reads 21938, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

Invoice table

Data space 15,467.375 MB

Rowcount 32561069

Transaction table

Data space 70,352.797 MB

Rowcount 30423982

Total number of extents for Transaction is 1284925.

Total number of extents for Invoice is 327445.

for IX_Transaction_InvUID index Extent Scan Fragmentation

was 90% afre drop and recreate index and then rebuild I succeeded to decrease it to 69% and then elapsed time for query became 25 second.

DBCC SHOWCONTIG scanning 'Transaction' table...

Table: 'Transaction' (1397580017); index ID: 8, database ID: 7

LEAF level scan performed.

- Pages Scanned................................: 121696

- Extents Scanned..............................: 15212

- Extent Switches..............................: 15211

- Avg. Pages per Extent........................: 8.0

- Scan Density [Best Count:Actual Count].......: 100.00% [15212:15212]

- Logical Scan Fragmentation ..................: 0.01%

- Extent Scan Fragmentation ...................: 69.18%

- Avg. Bytes Free per Page.....................: 1596.0

- Avg. Page Density (full).....................: 80.28%

For PK_Transaction

DBCC SHOWCONTIG scanning 'Transaction' table...

Table: 'Transaction' (1397580017); index ID: 1, database ID: 7

TABLE level scan performed.

- Pages Scanned................................: 9005158

- Extents Scanned..............................: 1132244

- Extent Switches..............................: 1470743

- Avg. Pages per Extent........................: 8.0

- Scan Density [Best Count:Actual Count].......: 76.54% [1125645:1470744]

- Logical Scan Fragmentation ..................: 33.81%

- Extent Scan Fragmentation ...................: 47.58%

- Avg. Bytes Free per Page.....................: 2388.4

- Avg. Page Density (full).....................: 70.49%

for IX_Invoice

DBCC SHOWCONTIG scanning 'Invoice' table...

Table: 'Invoice' (178099675); index ID: 15, database ID: 7

LEAF level scan performed.

- Pages Scanned................................: 479444

- Extents Scanned..............................: 60298

- Extent Switches..............................: 180199

- Avg. Pages per Extent........................: 8.0

- Scan Density [Best Count:Actual Count].......: 33.26% [59931:180200]

- Logical Scan Fragmentation ..................: 30.89%

- Extent Scan Fragmentation ...................: 96.19%

- Avg. Bytes Free per Page.....................: 1235.7

- Avg. Page Density (full).....................: 84.73%

for PK_Invoice

DBCC SHOWCONTIG scanning 'Invoice' table...

Table: 'Invoice' (178099675); index ID: 1, database ID: 7

TABLE level scan performed.

- Pages Scanned................................: 1979824

- Extents Scanned..............................: 248682

- Extent Switches..............................: 251615

- Avg. Pages per Extent........................: 8.0

- Scan Density [Best Count:Actual Count].......: 98.36% [247478:251616]

- Logical Scan Fragmentation ..................: 4.11%

- Extent Scan Fragmentation ...................: 91.68%

- Avg. Bytes Free per Page.....................: 301.1

- Avg. Page Density (full).....................: 96.28%

All Extent Scan Fragmentation are over 90% and I can not decrease them to 0.