Performance Probleme master-detail Datasets

[lxo]

Code:

select r.*
from MISCHKOPF r
left outer join MISCHKOPF_SPRACHE rs on rs.ID = r.LFDREZNR
left outer join DEKLKOPFFUSS dt on dt.DEKLID = r.DEKLTXT_ID
left outer join DEKLKOPFFUSS_SPRACHE dts on dts.ID = dt.DEKLID
left outer join SPRACHEN_SPRACHE ss on ss.SPRACHID = dt.sprachidaktiv

## MISCHKOPF ##
r.LFDREZNR = primary key
r.dekltxt_id = foreign key

## MISCHKOPF_SPRACHE ##
rs.ID = foreign key & primary key

## DEKLKOPFFUSS ##
dt.deklid = primary key
dt.sprachidaktiv = foreign key

## DEKLKOPFFUSS_SPRACHE ##
dts.id = foreign key & primary key

## SPRACHEN_SPRACHE ##
ss.sprachid primary key

so sieht der SQL im Grunde aus.

siehe unten IBExpert Sql-Analysis.

Der SQL an sich ist schnell, nur das fetchen dauert so lange (ca. 20.000 Datensätze).
Mir fällt nur auf das IB-Expert bei der Tabelle MISCHKOPF non-indexed-reads anzeigt aber ich verstehe nicht warum.

Code:

Plan
------------------------------------------------
PLAN JOIN (JOIN (JOIN (JOIN (R NATURAL,RS INDEX (RDB$PRIMARY503)),DT INDEX (RDB$PRIMARY579)),DTS INDEX (RDB$PRIMARY576)),SS INDEX (RDB$PRIMARY97))

Adapted Plan
------------------------------------------------
PLAN JOIN (JOIN (JOIN (JOIN (R NATURAL,RS INDEX (MISCHKOPF_SPRACHE_PKEY)),DT INDEX (DEKLKOPFFUSS_PKEY)),DTS INDEX (DEKLKOPFFUSS_SPRACHE_PKEY)),SS INDEX (SPRACHEN_SPRACHE_PKEY))

Query Time
------------------------------------------------
Prepare       : 31,00 ms
Execute       : 0,00 ms
Avg fetch time: 0,00 ms

Memory
------------------------------------------------
Current: 59.511.424
Max    : 60.633.704
Buffers: 3.000

Operations
------------------------------------------------
Read   : 0
Writes : 0
Fetches: 341
Marks  : 0


Enchanced Info:
+-------------------------------+-----------+-----------+-------------+---------+---------+---------+----------+----------+----------+
|          Table Name           |  Records  |  Indexed  | Non-Indexed | Updates | Deletes | Inserts | Backouts |  Purges  | Expunges |
|                               |   Total   |   reads   |    reads    |         |         |         |          |          |          |
+-------------------------------+-----------+-----------+-------------+---------+---------+---------+----------+----------+----------+
|SPRACHEN_SPRACHE               |         0 |        37 |           0 |       0 |       0 |       0 |        0 |        0 |        0 |
|MISCHKOPF_SPRACHE              |         0 |        14 |           0 |       0 |       0 |       0 |        0 |        0 |        0 |
|MISCHKOPF                      |         0 |         0 |          14 |       0 |       0 |       0 |        0 |        0 |        0 |
|DEKLKOPFFUSS_SPRACHE           |         0 |        13 |           0 |       0 |       0 |       0 |        0 |        0 |        0 |
|DEKLKOPFFUSS                   |         0 |        13 |           0 |       0 |       0 |       0 |        0 |        0 |        0 |
+-------------------------------+-----------+-----------+-------------+---------+---------+---------+----------+----------+----------+