Re: large numbers of inserts out of memory strategy - Mailing list pgsql-general

On 30 November 2017 at 05:22, Peter J. Holzer <hjp-pgsql@hjp.at> wrote:
> On 2017-11-29 08:32:02 -0600, Ted Toth wrote:
>> Yes I did generate 1 large DO block:
>>
>> DO $$
>> DECLARE thingid bigint; thingrec bigint; thingdataid bigint;
>> BEGIN
>> INSERT INTO thing
>> (ltn,classification,machine,source,thgrec,flags,serial,type) VALUES
>> ('T007336','THING',0,1025,7336,7,'XXX869977564',1) RETURNING id,thgrec
>> INTO thingid,thingrec;
>> INSERT INTO recnum_thing (recnum,thing_id) VALUES (thingrec,thingid);
>> INSERT INTO thingstatus
>>
(thing_id,nrpts,rmks_cs,force_type_id,ftn_cs,force_code,arr_cs,mask,toi_state,plot_id,signa_cs,lastchange,des_cs,rig_cs,ownship,correlation,maxrpts,rtn_cs,ctc_cs,group_mask,dep_cs)
>> VALUES (thingid,121,'{0,0,0,0}',440,0,23,0,0,0,'{23,-1,3803,3805,-1,-1,0,6}',0,1509459164,0,0,0,0,1000,0,0,0,0);
>> INSERT INTO thinger
>> (thing_id,spe_key,cse_unc,lat_spd,cov,dtg,lng,spd,ave_spd,cse,tol,nrpts,lat,alpha,sigma,spd_unc,lng_spd)
>> VALUES
(thingid,-1,0.0,-6.58197336634e-08,'{4.27624291532e-09,0.0,3.07802916488e-09,0.0,4.27624291532e-09,0.0,3.07802916488e-09,4.16110417234e-08,0.0,4.16110417234e-08}',1509459163,2.21596980095,0.000226273215958,1.0,0.0,0.10000000149,121,0.584555745125,10.0,4.23079740131e-08,0.0,-2.49999881907e-10);
>> INSERT INTO thingdata
>>
(thing_id,category,db_num,xref,org_type,trademark,shortname,fcode,platform,callsign,type,orig_xref,shipclass,home_base,uic,service,di,lngfixed,hull,precision,alert,flag,besufx,name,mmsi,catcode,ntds,imo,pn_num,chxref,threat,sconum,latfixed,db_type,pif,echelon,jtn,quantity,overwrite)
>> VALUES
(thingid,'XXX','','','','','004403704','23','','','','','UNEQUATED','','','','',0.0,'','{0,0,0,0,0}','','KS','','UNKNOWN','004403704','','','','','','AFD','',0.0,3,'','',0,0,0)
>> RETURNING id INTO thingdataid;
>> INSERT INTO thingnum (thingdata_id,thgnum,state,dtg,cmd) VALUES
>> (thingdataid,'013086',0,1502970401,'FOO');
>>
>> <repeated for each thing>
>>
>> END $$;
>>
>> Should I limit the number of 'thing' inserts within a DO block or
>> wrapping each 'thing' insert in it's own DO block?
>
> I would suggest getting rid of the do block entirely if that is
> possible. Just create lots of insert statements. You can get the current
> value of a sequence with currval('sequence_name').
>
> Alternately or in addition, since you are using python, you might want
> to insert directly into the database from python using psycopg2. For
> separate insert statements that should have about the same performance.
> (It is usually much faster to write to a csv file and load that with
> copy than to insert each row, but you don't do that and it might be
> difficult in your case).

Once upon a time, Slony-I used to use INSERT/UPDATE/DELETE to
do all of its work, so that the replication stream consisted of gigantic
numbers of INSERT/UPDATE/DELETE statements that had to be
parsed and processed.


--
When confronted by a difficult problem, solve it by reducing it to the
question, "How would the Lone Ranger handle this?"