Scientific poke method, or how to choose the configuration of a subdivision using benchmarks and an optimization algorithm

Hello.



I decided to share my find - the fruit of thought, trial and error.

By and large: this is not a find, of course - all this should be known for a long time, those who are engaged in applied statistic data processing and optimization of any systems, not necessarily a DBMS.

And: yes, they know, they write amusing articles on their researches, an example (UPD .: in the comments they pointed to a very interesting project: ottertune )

On the other hand: I don’t see the widespread mention, spread of this approach, on the Internet, among IT specialists, DBA ...



So to the point.



Suppose that we have a task: to set up a certain service system to service some kind of work.



It is known about this work: what it is, how the quality of this work is measured and what is the criterion for measuring this quality.



Let's also assume that it is more or less known, it is clear: how exactly work is done in (or with) this service system.



"More or less" means that there is an opportunity to prepare (or take somewhere) a tool, a utility with which you can synthesize and submit a test load to the system that is adequate enough to what will be in production, in conditions that are sufficient for working in production. ...



Well, let's say that we know a set of adjusting parameters of this service system, which can be used to configure this system, in terms of the productivity of its work.



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SQL> select status||' '||name from v$controlfile;
 /db/u14/oradata/XE/control01.ctl
SQL> select GROUP#||' '||MEMBER from v$logfile;
1 /db/u02/oradata/XE/redo01_01.log
2 /db/u02/oradata/XE/redo02_01.log
SQL> select FILE_ID||' '||TABLESPACE_NAME||' '||round(BYTES/1024/1024,2)||' '||FILE_NAME as col from dba_data_files;
4 UNDOTBS1 2208 /db/u14/oradata/XE/undotbs1_01.dbf
2 SLOB 128 /db/u14/oradata/XE/slob01.dbf
7 USERS 5 /db/u14/oradata/XE/users01.dbf
1 SYSTEM 860 /db/u14/oradata/XE/system01.dbf
3 SYSAUX 550 /db/u14/oradata/XE/sysaux01.dbf
5 MONITOR 128 /db/u14/oradata/XE/monitor.dbf
SQL> !cat /proc/mounts | egrep "\/db\/u[0-2]"
/dev/vda1 /db/u14 ext4 rw,noatime,nodiratime,data=ordered 0 0
/dev/mapper/vgsys-ora_redo /db/u02 xfs rw,noatime,nodiratime,attr2,nobarrier,inode64,logbsize=256k,noquota 0 0


SLOB-

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At the heart of SLOB is the β€œSLOB method.” The SLOB Method aims to test platforms

without application contention. One cannot drive maximum hardware performance

using application code that is, for example, bound by application locking or even

sharing Oracle Database blocks. That’s rightβ€”there is overhead when sharing data

in data blocks! But SLOBβ€”in its default deploymentβ€”is immune to such contention.

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function dotx()
{
local v_period="$2"
[ -z "v_period" ] && v_period="0"
source "/home/oracle/testingredotrac/config.conf"

$ORACLE_HOME/bin/sqlplus -S system/${v_system_pwd} << __EOF__
whenever sqlerror exit failure
set verify off
set echo off
set feedback off

define wnum="$1"
define period="$v_period"
set appinfo worker_&&wnum

declare
 v_upto number;
 v_key  number;
 v_tots number;
 v_cts  number;
begin
 select max(col1) into v_upto from system.testtab_&&wnum;
 SELECT (( SYSDATE - DATE '1970-01-01' ) * 86400 ) into v_cts FROM DUAL;
 v_tots := &&period + v_cts;
 while v_cts <= v_tots
 loop
  v_key:=abs(mod(dbms_random.random,v_upto));
  if v_key=0 then
   v_key:=1;
  end if;
  update system.testtab_&&wnum t
  set t.object_name=translate(dbms_random.string('a', 120), 'abcXYZ', '158249')
  where t.col1=v_key
  ;
  commit;
  SELECT (( SYSDATE - DATE '1970-01-01' ) * 86400 ) into v_cts FROM DUAL;
 end loop;
end;
/

exit
__EOF__
}
export -f dotx


:



echo "starting test, duration: ${TEST_DURATION}" >> "$v_logfile"
for((i=1;i<="$SQLSESS_COUNT";i++))
do
 echo "sql-session: ${i}" >> "$v_logfile"
 dotx "$i" "${TEST_DURATION}" &
done
echo "waiting..." >> "$v_logfile"
wait


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function createtable() {
source "/home/oracle/testingredotrac/config.conf"
$ORACLE_HOME/bin/sqlplus -S system/${v_system_pwd} << __EOF__
whenever sqlerror continue
set verify off
set echo off
set feedback off

define wnum="$1"
define ts_name="slob"

begin
 execute immediate 'drop table system.testtab_&&wnum';
exception when others then null;
end;
/

create table system.testtab_&&wnum tablespace &&ts_name as
select rownum as col1, t.*
from sys.dba_objects t
where rownum<1000
;
create index testtab_&&wnum._idx on system.testtab_&&wnum (col1);
--alter table system.testtab_&&wnum nologging;
--alter index system.testtab_&&wnum._idx nologging;
exit
__EOF__
}
export -f createtable

seq 1 1 "$SQLSESS_COUNT" | xargs -n 1 -P 4 -I {} -t bash -c "createtable \"{}\"" | tee -a "$v_logfile"
echo "createtable done" >> "$v_logfile"


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Database    DB Id    Instance     Inst Num  Startup Time   Release     RAC
~~~~~~~~ ----------- ------------ -------- --------------- ----------- ---
          2929910313 XE                  1 07-Sep-20 23:12 18.0.0.0.0  NO

Host Name             Platform                CPUs Cores Sockets   Memory (G)
~~~~ ---------------- ---------------------- ----- ----- ------- ------------
     billing.izhevsk1 Linux x86 64-bit           2     2       1         15.6

Snapshot       Snap Id     Snap Time      Sessions Curs/Sess Comment
~~~~~~~~    ---------- ------------------ -------- --------- ------------------
Begin Snap:       1630 07-Sep-20 23:12:27       55        .7
  End Snap:       1631 07-Sep-20 23:20:29       62        .6
   Elapsed:       8.03 (mins) Av Act Sess:       8.4
   DB time:      67.31 (mins)      DB CPU:      15.01 (mins)

Cache Sizes            Begin        End
~~~~~~~~~~~       ---------- ----------
    Buffer Cache:     1,392M              Std Block Size:         8K
     Shared Pool:       288M                  Log Buffer:   103,424K

Load Profile              Per Second    Per Transaction    Per Exec    Per Call
~~~~~~~~~~~~      ------------------  ----------------- ----------- -----------
      DB time(s):                8.4                0.0        0.00        0.20
       DB CPU(s):                1.9                0.0        0.00        0.04
       Redo size:        7,685,765.6              978.4
   Logical reads:           60,447.0                7.7
   Block changes:           47,167.3                6.0
  Physical reads:                8.3                0.0
 Physical writes:              253.4                0.0
      User calls:               42.6                0.0
          Parses:               23.2                0.0
     Hard parses:                1.2                0.0
W/A MB processed:                1.0                0.0
          Logons:                0.5                0.0
        Executes:           15,756.5                2.0
       Rollbacks:                0.0                0.0
    Transactions:            7,855.1


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  2. - . : [2,32];
  3. log_archive_max_processes : [1,8];
  4. commit_logging : batch|immediate;
  5. commit_wait : wait|nowait;
  6. log_buffer : [2,128] .
  7. log_checkpoint_timeout : [60,1200]
  8. db_writer_processes : [1,4]
  9. undo_retention : [30;300]
  10. transactions_per_rollback_segment : [1,8]
  11. disk_asynch_io : true|false;
  12. filesystemio_options : none|setall|directIO|asynch;
  13. db_block_checking : OFF|LOW|MEDIUM|FULL;
  14. db_block_checksum : OFF|TYPICAL|FULL;


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GA::ga
cat( "", file=v_logfile, sep="\n", append=F)

pSize = 10
elitism_value=1
pmutation_coef=0.8
pcrossover_coef=0.1
iterations=50

gam=GA::ga(type="real-valued", fitness=evaluate,
lower=c(32,2, 1,1,1,2,60,1,30,1,0,0, 0,0), upper=c(1024,32, 8,10,10,128,800,4,300,8,10,40, 40,30),
popSize=pSize,
pcrossover = pcrossover_coef,
pmutation = pmutation_coef,
maxiter=iterations,
run=4,
keepBest=T)
cat( "GA-session is done" , file=v_logfile, sep="\n", append=T)
gam@solution


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evaluate=function(p_par) {
v_module="evaluate"
v_metric=0
opn=NULL
opn$rg_size=round(p_par[1],digit=0)
opn$rg_count=round(p_par[2],digit=0)
opn$log_archive_max_processes=round(p_par[3],digit=0)
opn$commit_logging="BATCH"
if ( round(p_par[4],digit=0) > 5 ) {
 opn$commit_logging="IMMEDIATE"
}
opn$commit_logging=paste("'", opn$commit_logging, "'",sep="")

opn$commit_wait="WAIT"
if ( round(p_par[5],digit=0) > 5 ) {
 opn$commit_wait="NOWAIT"
}
opn$commit_wait=paste("'", opn$commit_wait, "'",sep="")

opn$log_buffer=paste(round(p_par[6],digit=0),"m",sep="")
opn$log_checkpoint_timeout=round(p_par[7],digit=0)
opn$db_writer_processes=round(p_par[8],digit=0)
opn$undo_retention=round(p_par[9],digit=0)
opn$transactions_per_rollback_segment=round(p_par[10],digit=0)
opn$disk_asynch_io="true"
if ( round(p_par[11],digit=0) > 5 ) {
 opn$disk_asynch_io="false"
} 

opn$filesystemio_options="none"
if ( round(p_par[12],digit=0) > 10 && round(p_par[12],digit=0) <= 20 ) {
 opn$filesystemio_options="setall"
}
if ( round(p_par[12],digit=0) > 20 && round(p_par[12],digit=0) <= 30 ) {
 opn$filesystemio_options="directIO"
}
if ( round(p_par[12],digit=0) > 30 ) {
 opn$filesystemio_options="asynch"
}

opn$db_block_checking="OFF"
if ( round(p_par[13],digit=0) > 10 && round(p_par[13],digit=0) <= 20 ) {
 opn$db_block_checking="LOW"
}
if ( round(p_par[13],digit=0) > 20 && round(p_par[13],digit=0) <= 30 ) {
 opn$db_block_checking="MEDIUM"
}
if ( round(p_par[13],digit=0) > 30 ) {
 opn$db_block_checking="FULL"
}

opn$db_block_checksum="OFF"
if ( round(p_par[14],digit=0) > 10 && round(p_par[14],digit=0) <= 20 ) {
 opn$db_block_checksum="TYPICAL"
}
if ( round(p_par[14],digit=0) > 20 ) {
 opn$db_block_checksum="FULL"
}

v_vector=paste(round(p_par[1],digit=0),round(p_par[2],digit=0),round(p_par[3],digit=0),round(p_par[4],digit=0),round(p_par[5],digit=0),round(p_par[6],digit=0),round(p_par[7],digit=0),round(p_par[8],digit=0),round(p_par[9],digit=0),round(p_par[10],digit=0),round(p_par[11],digit=0),round(p_par[12],digit=0),round(p_par[13],digit=0),round(p_par[14],digit=0),sep=";")
cat( paste(v_module," try to evaluate vector: ", v_vector,sep="") , file=v_logfile, sep="\n", append=T)

rc=make_additional_rgroups(opn)
if ( rc!=0 ) {
 cat( paste(v_module,"make_additional_rgroups failed",sep="") , file=v_logfile, sep="\n", append=T)
 return (0)
}

v_rc=0
rc=set_db_parameter("log_archive_max_processes", opn$log_archive_max_processes)
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("commit_logging", opn$commit_logging )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("commit_wait", opn$commit_wait )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("log_buffer", opn$log_buffer )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("log_checkpoint_timeout", opn$log_checkpoint_timeout )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("db_writer_processes", opn$db_writer_processes )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("undo_retention", opn$undo_retention )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("transactions_per_rollback_segment", opn$transactions_per_rollback_segment )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("disk_asynch_io", opn$disk_asynch_io )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("filesystemio_options", opn$filesystemio_options )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("db_block_checking", opn$db_block_checking )
if ( rc != 0 ) {  v_rc=1 }
rc=set_db_parameter("db_block_checksum", opn$db_block_checksum )
if ( rc != 0 ) {  v_rc=1 }

if ( rc!=0 ) {
 cat( paste(v_module," can not startup db with that vector of settings",sep="") , file=v_logfile, sep="\n", append=T)
 rc=stop_db("immediate")
 rc=create_spfile()
 rc=start_db("")
 rc=remove_additional_rgroups(opn)
 return (0)
}

rc=stop_db("immediate")
rc=start_db("")
if ( rc!=0 ) {
 cat( paste(v_module," can not startup db with that vector of settings",sep="") , file=v_logfile, sep="\n", append=T)
 rc=stop_db("abort")
 rc=create_spfile()
 rc=start_db("")
 rc=remove_additional_rgroups(opn)
 return (0)
}

rc=run_test()
v_metric=getmetric()

rc=stop_db("immediate")
rc=create_spfile()
rc=start_db("")
rc=remove_additional_rgroups(opn)

cat( paste("result: ",v_metric," ",v_vector,sep="") , file=v_logfile, sep="\n", append=T)
return (v_metric)
}


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set_db_parameter
set_db_parameter=function(p1, p2) {
v_module="set_db_parameter"
v_cmd="/home/oracle/testingredotrac/set_db_parameter.sh"
v_args=paste(p1," ",p2,sep="")

x=system2(v_cmd, args=v_args, stdout=T, stderr=T, wait=T)
if ( length(attributes(x)) > 0 ) {
 cat(paste(v_module," failed with: ",attributes(x)$status," ",v_cmd," ",v_args,sep=""), file=v_logfile, sep="\n", append=T)
 return (attributes(x)$status)
}
else {
 cat(paste(v_module," ok: ",v_cmd," ",v_args,sep=""), file=v_logfile, sep="\n", append=T)
 return (0)
}
}


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cat( paste("result: ",v_metric," ",v_vector,sep="") , file=v_logfile, sep="\n", append=T)


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x=NULL
v_data_file=paste('/tmp/data1.dat',sep="")
x=read.table(v_data_file, header = TRUE, sep = ";", dec=",", quote = "\"'", stringsAsFactors=FALSE)
colnames(x)=c('metric','rgsize','rgcount','lamp','cmtl','cmtw','lgbffr','lct','dbwrp','undo_retention','tprs','disk_async_io','filesystemio_options','db_block_checking','db_block_checksum')

idxTrain=sample(nrow(x),as.integer(nrow(x)*0.7))
idxNotTrain=which(! 1:nrow(x) %in% idxTrain )
TrainDS=x[idxTrain,]
ValidateDS=x[idxNotTrain,]

library(randomForest)
#mtry=as.integer( sqrt(dim(x)[2]-1) )
rf=randomForest(metric ~ ., data=TrainDS, ntree=40, mtry=3, replace=T, nodesize=2, importance=T, do.trace=10, localImp=F)
ValidateDS$predicted=predict(rf, newdata=ValidateDS[,colnames(ValidateDS)!="metric"], type="response")
sum((ValidateDS$metric-ValidateDS$predicted)^2)
rf$importance


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In practice, this is: the exchange of the costs of understanding a custom system, for the costs of preparing such testing of the system's operation.



Separately, I note: in this approach, the degree of adequacy of the system testing to the conditions of its operation that it will have in production operation is critically important.



Thanks for your attention, time.




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