Huge difference in read time Oracle vs MaxDB

[Former Member]

Hello,

A few weeks ago, we migrated from a 32-bit Oracle to an 64-bit MaxDB database.

Now, the read time at the MaxDB-database is very bad comparing to our Oracle database.

For example ( It's an IS-H table):

SELECT a_{lnrls a}refnr b_{leist a}dbcnr

INTO TABLE it_nlei

FROM nlei AS a INNER JOIN nlei AS b

ON b_{lnrls = a}refnr

FOR ALL ENTRIES IN it_vbrp

WHERE a~lnrls = it_vbrp-vgbel.

The field LNRLS is a unique field in the table NLEI, with an unique index on this field. The execution plans for both systems are using the same index.

But with a selection of 10000 entries in it_vbrp the selection on the MaxDB system takes 477 seconds and the same selection on an Oracle database takes 13 seconds. Both systems are containing the same data.

<b>Does anybody know this problem ????

Can it have something to do with our DB-parameters ???</b>

Here is a list of some of our parameters:

rsdb/prefer_fix_blocking 0

rsdb/prefer_join 0

SAPSYSTEM 00

enque/serverinst 00

sapsystem 00

dbs/ada/register_appl_info 1

enque/encni/threadcount 1

rdisp/wp_no_enq 1

rsdb/prefer_in_itab_opt 1

rsdb/prefer_union_all 1

icm/max_threads 10

rsdb/reco_sleep_time 10

enque/server/query_block_count 100

login/system_client 100

rsdb/reco_trials 100

enque/adm-queue/size 1000

enque/encni/max_clients 1000

enque/enq-queue/size 1000

enque/enrep/req_block_count 1000

enque/enrep/store_size 1000

enque/repl-queue/size 1000

enque/server/req_block_count 1000

rdisp/wp_ca_blk_no 1000

sap/bufdir_entries 10000

jvmx/blocksize_KB 1024

enque/server/codepage 1100

rslg/send_daemon/talk_port 1300

enque/server/query_block_size 131072

zcsa/db_max_buftab 15000

rdisp/PG_SHM 16384

rdisp/wp_no_spo 2

rdisp/wp_no_vb2 2

gw/max_conn 2000

gw/max_sys 2000

rdisp/appc_ca_blk_no 2000

rdisp/max_arq 2000

rdisp/max_comm_entries 2000

rdisp/ses_tab_max_no 2000

rdisp/tm_max_no 2000

rsdb/obj/buffersize 20000

rsdb/obj/max_objects 20000

abap/heaplimit 20000000

zcsa/presentation_buffer_area 20000000

ipc/shm_psize_10 200000000

ztta/roll_extension_dia 2000000000

ztta/roll_extension_nondia 2000000000

em/initial_size_MB 2040

em/max_size_MB 2040

em/blocksize_KB 2048

enque/table_size 20480

rsdb/ntab/sntabsize 2500

gw/max_overflow_size 25000000

rdisp/wp_no_vb 3

rdisp/wppriv_max_no 3

rsdb/ntab/entrycount 30000

rtbb/buffer_length 30000

j2ee/enq/port 32

enque/server/req_block_size 32768

j2ee/ms/port 36

rdisp/max_wprun_time 36000

rslg/send_daemon/listen_port 3700

rslg/collect_daemon/listen_port 3900

rsdb/ntab/ftabsize 39000

rsdb/ntab/irbdsize 4000

rslg/collect_daemon/talk_port 4000

igs/mux/port 40000

igs/pw/1/port 40001

igs/pw/2/port 40002

igs/listener/http 40080

rsdb/max_blocking_factor 5

rsdb/min_blocking_factor 5

rsdb/max_in_blocking_factor 50

rsdb/min_in_blocking_factor 50

rsdb/cua/buffersize 5000

scsa/shm/key 58900100

rslg/swap/lock 58900200

rslg/append/lock 58900300

rdisp/wp_no_btc 6

PHYS_MEMSIZE 6144

abap/buffersize 650000

login/fails_to_user_lock 7

ipc/shm_psize_40 70000000

jvmx/max_global_heap_extend_size_MB 8

rdisp/wp_no_dia 8

zcsa/table_buffer_area 80000000

rdisp/ROLL_SHM 8192

auth/auth_number_in_userbuffer 9000

FN_ABAPPROT ABAPPROT

dbms/type ada

FN_ALALERTS ALALERTS

FN_ALFILTER ALFILTER

FN_ALMTTREE ALMTTREE

FN_ALPARAMS ALPARAMS

FN_ALPERFHI ALPERFHI

FN_ASTAT astat

FN_ATRAPATH AT00++++

FN_AUDIT audit_++++++++

FN_DBMS BINDBE

FN_BDCLOG BIYZQCI-B00

igs/ip/bwgis bwgis.so

FN_SPOOLDIH D+++++++

FN_DBPASSWD DBPASSWD

zcsa/installed_languages DEN

FN_DW disp+work

FN_DPLCOM dplcomlib.so

INSTANCE_NAME DVEBMGS00

[Former Member]

Hello,

to analyze this kind of problem in detail we need to have an official custoemr call on component BC-DB-SDB. there can be a lot of reasons for performance problems.

Please give us the following information in this call:

1. Database Version -> Please check your Database parameter settings with SAP Note 814704 (Version 7.6.) or 767635 (Version 7.5.).

2. Open an R/3-Connection to your system and store the LOGON Data in the secure area.

If you want to have global information about MaxDB Tuning have a look into the MaxDB SDN Wiki -> Tuning MaxDB

<a href="https://wiki.sdn.sap.com/wiki/x/jRI">https://wiki.sdn.sap.com/wiki/x/jRI</a>

Regards, Christiane Hienger

MaxDB Development Support

SAP AG