Advanced Shell Scripting for Oracle professionals

ADVANCED SHELL SCRIPTING

FOR ORACLE

PROFESSIONALS

JEVGEŅIJS REUTS

INTRO

• WHO? - Oracle Applications Database Consultant @ Pythian

- Oracle Database Administrator Certified Professional

- Working with Oracle since 2006

- Not shell scripting guru

• WHY? - Interesting case to share with community

© 2015 Pythian Confidential 2

BUSINESS CASE

• Migrate users for particular department from on

premise Oracle Internet Directory 10g instance

to Oracle Internet Directory 11g instance located

in Amazon (AWS)


CUSTOMER REQUIREMENTS

• Migrate users to new basedn or “tree” in OID 11g

• CSV with usernames provided

• Initial downtime requirement max 4h

• Later changed to “No Downtime allowed”


INITIAL REVIEW

• CSV contains 2,2M usernames

• OID cn: attribute = username

– Example:

USER_ID,SOURCE_USER_ID

317149,SNOWLIS

• Usernames has no pattern for filtering

• Total amount of users in 10g OID 7,7M


OID USER RECORD EXAMPLE [oracle@oid10g ~]$ ldapsearch -h localhost -p 389 -D "cn=orcladmin" -w password -L -s sub -b "cn=users,dc=test,dc=example,dc=com" "(cn=SNOWLIS)" "*"

dn: cn=SNOWLIS, cn=users,dc=test,dc=example,dc=com

authpassword;oid: {SASL/MD5-DN}E5GNW+/uc5Q4vaUHTpoV8w==

authpassword;oid: {SASL/MD5-U}em8szBiI6lQe7oSZys9S6w==

authpassword;oid: {SASL/MD5}OIcK6dZZFlu7kZOw8+RxEQ==

authpassword;orclcommonpwd: {MD5}UVSevJPyPkXxUHoK1QMOfw==

authpassword;orclcommonpwd: {X- ORCLLMV}C5A7687D19248DD11D71060D896B7A46

authpassword;orclcommonpwd: {X- ORCLNTV}769F744EC914822D37C66B8EFBFD68F9

authpassword;orclcommonpwd: {X- ORCLIFSMD5}AMLZgqATptPU1TkLgpGh1w==

authpassword;orclcommonpwd: {X- ORCLWEBDAV}Fg/OrZz6AEATMeJMXWm19A==

cn: SNOWLIS

mail: [email protected]

objectclass: orcluserv2

objectclass: organizationalPerson

objectclass: top

objectclass: person

objectclass: inetorgperson

orclisenabled: ENABLED

orclpassword: {x- orcldbpwd}1.0:059A0F10E478B5BB

sn: SNOWLIS

uid: SNOWLIS

userpassword: {SHA}1btDzs8cj+zHwHLzsgEaUCJ0nn0=


INITIAL APPROACH

• Create shell script

• Script will read usernames from csv line by line

• With ldapsearch will check if entry exists

• If exists with ldapsearch again dumping all the entry content to ldif file

• Replace basedn or “tree” with sed

• Import users with native OID bulkload utility (uses SQL*Loader, downtime required)


INITIAL APPROACH EXAMPLE cat ${v_base_dir}/usernames.csv | grep -v "USER_ID,SOURCE_USER_ID" | awk 'BEGIN

{FS=","}{print $2}' | while read v_username ; do

v_ldap_result=$(ldapsearch -h localhost -p 389 -D "cn=orcladmin" -w ${v_oid_pwd} -L -s

sub -b "cn=users,dc=test,dc=exaple,dc=com" "(cn=${v_username})" "dn" | wc -l)

if [ ${v_ldap_result} -gt 0 ] ; then

ldapsearch -h localhost -p 389 -D "cn=orcladmin" -w ${v_oid_pwd} -L -s sub -b

"cn=users,dc=test,dc=exaple,dc=com" "(cn=${v_username})" "*" >>

${v_base_dir}/content_generated_from_cvs.ldif

echo "" >> ${v_base_dir}/content_generated_from_cvs.ldif

else

echo ${v_username} >> ${v_base_dir}/users_not_in_oid.log

fi

done


PROBLEM WITH INITIAL APPROACH

• Single ldapsearch operation takes ~1s

• For 2,2M users that is 2,2M seconds

• Or 611 hours or 25 days

• Not an option


APPROACH 2

• Full export of OID basedn or “tree” ldifwrite connect=“SID" basedn="cn=users,dc=test,dc=example,dc=com" ldiffile=content_generated_from_cvs.ldif threads=8

• Create shell script to read full export file and compare usernames against CSV file

• If user exists dumping all the entry content to ldif file

• Replace basedn or “tree” with sed

• Import users with native OID bulkload utility (uses SQL*Loader, downtime required)


PROBLEM WITH APPROACH 2

• Full export file size 9GB

• Total 7,7M users x 21 attribute

• Huge amount of lines

• CSV file has 2,2M lines

• HOW TO HANDLE THIS EFFICIENTLY?


WAY TO GO

• Use BASH associative array

• Load username from CSV to array

• Proceed reading full user dump file against array

• Loading 2,2M row from CSV to array took 50

minutes

• NOTE: BASH associative arrays are available

since bash version 4.0


BASH ASSOCIATIVE ARRAY # load csv to array

declare -A myarray1

while read line_data

do

myarray1[${line_data}]=1

done <<< "$(cat usernames.csv | grep -v "USER_ID,SOURCE_USER_ID"

| awk 'BEGIN {FS=","}{print $2}')“

[oracle@oid10g ~]$ echo ${myarray1[SNOWLIS]}

1

[oracle@oid10g ~]$ echo ${myarray1[SNOWLIS1]}


BASH ASSOCIATIVE ARRAY

• Use BASH associative array

• Load username from CSV to array

• Proceed reading full user dump file against array

• Loading 2,2M row from CSV to array took 50

minutes


CONSTRUCTING MAIN BLOCK

• Reading full dump file

• If dn: attribute, then extracting cn: user attribute

• Checking if cn: or username persist in array

• If persists in array, setting print flag and dumping

all line until next dn: attribute


CONSTRUCTING MAIN BLOCK

while read v_user_entry_item ; do

v_user_entry_res=$(echo ${v_user_entry_item}| grep "^dn:" | wc -l)

if [ ${v_user_entry_res} -gt 0 ] ; then

v_username=$(echo ${v_user_entry_item} | awk 'BEGIN {FS=","}{print $1}' | awk 'BEGIN

{FS="="}{print $2}')

if [ "1" == "${myarray1[$v_username]}" ]; then

print_status=1

else

print_status=0

fi

fi

if [ ${print_status} = "1" ] ; then

echo ${v_user_entry_item} >> content_to_load.ldif

fi

done < ${v_base_dir}/content_generated_from_cvs.ldif


RUNNING THE SCRIPT

• Script started, working as expected

• But still slow, target to complete > 24h

• Why script taking so long?

• strace -c -f -p <pid>

• Cat, grep, sed and awk utilities

• When bash runs a command it forks a child

process


STRACE OUTPUT strace -c -f -p 17011

% time seconds usecs/call calls errors syscall

------ ----------- ----------- --------- --------- ----------------

95.11 0.134360 1600 84 28 wait4

1.48 0.002091 6 336 fstat

1.16 0.001635 3 486 dup2

0.93 0.001316 0 3140 rt_sigprocmask

0.20 0.000280 1 249 write

0.19 0.000264 2 112 getegid

0.18 0.000251 1 420 mmap

0.17 0.000246 1 375 open

0.15 0.000213 0 841 57 close

0.10 0.000141 0 1035 fcntl

0.08 0.000111 0 280 84 stat

0.05 0.000072 1 140 28 access

0.04 0.000058 2 28 munmap

0.04 0.000056 0 1000 lseek

0.03 0.000049 1 84 brk

0.03 0.000041 0 196 mprotect

0.02 0.000030 0 621 rt_sigaction

0.02 0.000029 0 112 getuid

0.02 0.000028 0 557 557 ioctl

0.00 0.000000 0 669 read

------ ----------- ----------- --------- --------- ----------------

100.00 0.141271 11232 754 total


BASH STRING PROCESSING ${parameter:offset:length}

sting="dn: cn=SNOWLIS, cn=users,dc=test,dc=example,dc=com"

echo ${string:0:3}

dn:

${parameter:offset}

sting= "cn: SNOWLIS"

echo ${string:4}

SNOWLIS


BASH STRING PROCESSING

sting=snowlis

echo ${string^^}

SNOWLIS

sting=SNOWLIS

echo ${string,,}

snowlis


REWRITTEN SCRIPT VERSION echo "Processing full export LDIF..."

print_status=0

# Reading the user list

while read v_user_entry_item ; do

if [ "X${v_user_entry_item:0:3}" == "Xdn:" ] ; then


echo "${TMP}" >> content_to_load.ldif

print_status=0

fi

TMP=""

fi

if [ "X${v_user_entry_item:0:4}" == "Xcn: " ] ; then

v_user_entry_item_cn=${v_user_entry_item:4}

if [ "1" == "${myarray1[${v_user_entry_item_cn^^}]}" ]; then

print_status=1

myarray1[${v_user_entry_item_cn^^}]=2

else

print_status=0

fi

fi

TMP="${TMP}

${v_user_entry_item}"

done < ${v_base_dir}/content_generated_from_cvs.ldif


echo "${TMP}" >> content_to_load.ldif

fi


RESULTS

• Script execution time decreased to 4h

• Still not fast enough

• Redesign the script to run in 4 parallel sessions

• Split full dump file with split command to 4 parts

• Merge four output file

• Script execution time decreased to 1h


POST PROCESSING & IMPORT

• Replace basedn or “tree” with sed sed -i

"s/cn=Users,dc=test,dc=example,dc=com/cn=users,ou=he,dc=te

st,dc=example2,dc=net/g" content_to_load.ldif

• Remove internal OID attributes with sed

• Run import with ldapadd native OID tool ldapadd -h localhost -p 3060 -D "cn=orcladmin" -w <pwd> -f

content_to_load.ldif -c


CONCLUSION

• Cat, awk, sed and grep utilities are efficient and useful working with small files

• Working with huge size files use bash string processing where possible

• Bash associative arrays can help and improve performance of your scripts

BEER TIME !!!!


Date post:	15-Apr-2017
Category:	Education
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Advanced Shell Scripting for Oracle professionals

Education