IiCPU zanamhlanje zineentsimbi ezininzi. Kangangeminyaka, izicelo bezithumela imibuzo koovimba beenkcukacha ngendlela efanayo. Ukuba ngumbuzo wengxelo kwimiqolo emininzi etafileni, ibaleka ngokukhawuleza xa usebenzisa ii-CPU ezininzi, kwaye i-PostgreSQL ikwazile ukwenza oku ukusukela kwinguqulo ye-9.6.
Kuthathe iminyaka emi-3 ukuphumeza inqaku lombuzo onxuseneyo - kuye kwafuneka ukuba siyibhale kwakhona ikhowudi kumanqanaba ahlukeneyo okwenziwa kombuzo. I-PostgreSQL 9.6 yazisa isiseko sokuphucula ngakumbi ikhowudi. Kwiinguqulelo ezilandelayo, ezinye iintlobo zemibuzo ziqhutywa ngokuhambelanayo.
Zi thintelo
- Sukwenza ufezekiso oluhambelanayo ukuba zonke iicores sele zixakekile, kungenjalo ezinye izicelo ziyakucotha.
- Okona kubaluleke kakhulu, ukusetyenzwa ngokunxuseneyo kunye namaxabiso aphezulu e-WORK_MEM kusebenzisa inkumbulo eninzi- ukujoyina i-hash nganye okanye uhlobo luthatha imemori ye-work_mem.
- Imibuzo ye-OLTP ye-latency esezantsi ayinakukhawuleziswa ngokufezekiswa okufanayo. Kwaye ukuba umbuzo ubuyisela umqolo omnye, ukusetyenzwa kwe-parallel kuya kuyicothisa kuphela.
- Abaphuhlisi bathanda ukusebenzisa ibhentshi ye-TPC-H. Mhlawumbi unemibuzo efanayo yokuphunyezwa okuhambelanayo okugqibeleleyo.
- KHETHA kuphela imibuzo ngaphandle kokutshixa isivisa esenziwa ngokuhambelanayo.
- Ngamanye amaxesha isalathisi esifanelekileyo singcono kunokuskena kwetafile elandelelanayo kwimowudi ehambelanayo.
- Ukunqumamisa imibuzo kunye nekhesa azixhaswanga.
- Imisebenzi yefestile kunye nemisebenzi ecwangcisiweyo yesethi edibeneyo ayihambelani.
- Awuzuzi nto kumthwalo we-I/O womsebenzi.
- Azikho iindlela zokuhlela ezihambelanayo. Kodwa imibuzo eneentlobo inokuqhutywa ngokuhambelanayo kwezinye iinkalo.
- Faka endaweni ye-CTE (NGE ...) ngendlwane KHETHA ukwenza umsebenzi ohambelanayo.
- Izisongelo zedatha yomntu wesithathu azikaxhasi ukusetyenzwa ngokunxuseneyo (kodwa zinako!)
- FULL OUTER JOIN ayixhaswanga.
- max_rows ivala inkqubo edityanisiweyo.
- Ukuba umbuzo unomsebenzi ongaphawulwanga PARALLEL SAFE, izakuba ngumsonto omnye.
- Inqanaba lentengiselwano yeSERIALIZABLE ivala ukusetyenzwa ngokunxuseneyo.
Indawo yovavanyo
Abaphuhlisi bePostgreSQL bazame ukunciphisa ixesha lokuphendula lemibuzo ye-TPC-H yebhentshi. Khuphela umlinganiselo kunye . Oku kusetyenziso olungekho semthethweni lwebhentshi ye-TPC-H - hayi kwisiseko sedatha okanye uthelekiso lwehardware.
- Khuphela TPC-H_Tools_v2.17.3.zip (okanye inguqulelo entsha) .
- Phinda unike igama elithi makefile.suite kwiMakefile kwaye utshintshe njengoko kuchaziwe apha: . Qokelela ikhowudi kunye nomyalelo wokwenza.
- Veza idatha:
./dbgen -s 10yenza i-database ye-23 GB. Oku kwanele ukubona umahluko ekusebenzeni kwemibuzo ehambelanayo kunye ne-non-parallel. - Guqula iifayile
tblвcsv с forиsed. - Cola indawo yokugcina
pg_tpchkwaye ukhuphele iifayilecsvвpg_tpch/dss/data. - Yenza imibuzo ngomyalelo
qgen. - Layisha idatha kwisiseko sedatha ngomyalelo
./tpch.sh.
Ukuskena okulandelelanayo okunxuseneyo
Inokukhawuleza hayi ngenxa yokufunda ngokuhambelanayo, kodwa ngenxa yokuba idatha isasazwe kuzo zonke ii-CPU cores ezininzi. Kwiinkqubo zokusebenza zanamhlanje, iifayile zedatha yePostgreSQL zigcinwe kakuhle. Ngokufunda kwangaphambili, kuyenzeka ukuba ufumane ibhloko enkulu kwindawo yokugcina kunezicelo zedaemon yePG. Ke ngoko, ukusebenza kombuzo akukhawulelwanga yidiski I/O. Isebenzisa imijikelo ye-CPU ukuya:
- funda imiqolo ibenye ngexesha kumaphepha etafile;
- thelekisa amaxabiso omtya kunye neemeko
WHERE.
Masiqhube umbuzo olula select:
tpch=# explain analyze select l_quantity as sum_qty from lineitem where l_shipdate <= date '1998-12-01' - interval '105' day;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------
Seq Scan on lineitem (cost=0.00..1964772.00 rows=58856235 width=5) (actual time=0.014..16951.669 rows=58839715 loops=1)
Filter: (l_shipdate <= '1998-08-18 00:00:00'::timestamp without time zone)
Rows Removed by Filter: 1146337
Planning Time: 0.203 ms
Execution Time: 19035.100 msUkuskena okulandelelanayo kuvelisa imiqolo emininzi kakhulu ngaphandle kodityaniso, ngoko umbuzo wenziwe ngondoqo we-CPU enye.
Ukuba uyongeza SUM(), unokubona ukuba ukuhamba komsebenzi okumbini kuya kunceda ukukhawulezisa umbuzo:
explain analyze select sum(l_quantity) as sum_qty from lineitem where l_shipdate <= date '1998-12-01' - interval '105' day;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------
Finalize Aggregate (cost=1589702.14..1589702.15 rows=1 width=32) (actual time=8553.365..8553.365 rows=1 loops=1)
-> Gather (cost=1589701.91..1589702.12 rows=2 width=32) (actual time=8553.241..8555.067 rows=3 loops=1)
Workers Planned: 2
Workers Launched: 2
-> Partial Aggregate (cost=1588701.91..1588701.92 rows=1 width=32) (actual time=8547.546..8547.546 rows=1 loops=3)
-> Parallel Seq Scan on lineitem (cost=0.00..1527393.33 rows=24523431 width=5) (actual time=0.038..5998.417 rows=19613238 loops=3)
Filter: (l_shipdate <= '1998-08-18 00:00:00'::timestamp without time zone)
Rows Removed by Filter: 382112
Planning Time: 0.241 ms
Execution Time: 8555.131 msUdityaniso olunxuseneyo
I-Parallel Seq Scan node ivelisa imiqolo yodityaniso oluyinxenye. Indawo ye-"Partial Aggregate" icheba le migca isebenzisa SUM(). Ekugqibeleni, ikhawuntara ye-SUM kwinkqubo nganye yabasebenzi iqokelelwa ngendawo ethi “Qoqa”.
Isiphumo sokugqibela sibalwa nge "Finalize Aggregate" node. Ukuba uneyakho imisebenzi yokudibanisa, ungalibali ukuyiphawula njenge "parallel safe".
Inani leenkqubo zabasebenzi
Inani leenkqubo zabasebenzi linganyuswa ngaphandle kokuphinda kuqalelwe umncedisi:
explain analyze select sum(l_quantity) as sum_qty from lineitem where l_shipdate <= date '1998-12-01' - interval '105' day;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------
Finalize Aggregate (cost=1589702.14..1589702.15 rows=1 width=32) (actual time=8553.365..8553.365 rows=1 loops=1)
-> Gather (cost=1589701.91..1589702.12 rows=2 width=32) (actual time=8553.241..8555.067 rows=3 loops=1)
Workers Planned: 2
Workers Launched: 2
-> Partial Aggregate (cost=1588701.91..1588701.92 rows=1 width=32) (actual time=8547.546..8547.546 rows=1 loops=3)
-> Parallel Seq Scan on lineitem (cost=0.00..1527393.33 rows=24523431 width=5) (actual time=0.038..5998.417 rows=19613238 loops=3)
Filter: (l_shipdate <= '1998-08-18 00:00:00'::timestamp without time zone)
Rows Removed by Filter: 382112
Planning Time: 0.241 ms
Execution Time: 8555.131 msKwenzeka ntoni apha? Kwakukho amaxesha e-2 iinkqubo ezininzi zomsebenzi, kwaye isicelo saba ngamaxesha e-1,6599 kuphela ngokukhawuleza. Izibalo zinika umdla. Sasineenkqubo zabasebenzi ezi-2 kunye nenkokeli enye. Emva kotshintsho yaba yi-1+4.
Ukukhawuleza kwethu okuphezulu ukusuka kwi-parallel processing: 5/3 = 1,66 (6) amaxesha.
Isebenza njani?
Iinkqubo
Ukuphunyezwa kwesicelo kuhlala kuqala ngenkqubo ekhokelayo. Inkokeli yenza yonke into engahambelaniyo kunye nokulungiswa okufanayo. Ezinye iinkqubo ezenza izicelo ezifanayo zibizwa ngokuba ziinkqubo zabasebenzi. Ukusetyenzwa kweParallel kusebenzisa iziseko zophuhliso (ukusuka kwinguqulo 9.4). Ekubeni ezinye iindawo ze-PostgreSQL zisebenzisa iinkqubo kunemicu, umbuzo oneenkqubo ze-3 zabasebenzi unokuba ngamaxesha e-4 ngokukhawuleza kunokucubungula kwendabuko.
Ukusebenzisana
Iinkqubo zabasebenzi zinxibelelana nenkokeli ngomgca wemiyalezo (esekelwe kwimemori ekwabelwana ngayo). Inkqubo nganye inemigca emi-2: yeempazamo kunye nee-tuples.
Zingaphi iinkqubo zokusebenza ezifunekayo?
Ubuncinci bomda uchazwe yiparameter . Umgijimi ocelayo emva koko uthatha iinkqubo zabasebenzi ukusuka echibini elilinganiselwe yiparameter . Umda wokugqibela , oko kukuthi, inani elipheleleyo leenkqubo zangasemva.
Ukuba bekungenakwenzeka ukwaba inkqubo yomsebenzi, ukusetyenzwa kuya kuba yinkqubo enye.
Umcwangcisi wombuzo unokunciphisa ukuhamba komsebenzi ngokuxhomekeke kubukhulu betafile okanye isalathisi. Kukho iiparamitha zale nto и .
set min_parallel_table_scan_size='8MB'
8MB table => 1 worker
24MB table => 2 workers
72MB table => 3 workers
x => log(x / min_parallel_table_scan_size) / log(3) + 1 workerNgalo lonke ixesha itheyibhile iphindwe ka-3 ngobukhulu min_parallel_(index|table)_scan_size, I-Postgres yongeza inkqubo yabasebenzi. Inani lokuhamba komsebenzi alisekelwanga kwiindleko. Ukuxhomekeka kwisetyhula kwenza ukuphunyezwa okuntsokothileyo kube nzima. Kunoko, umcwangcisi usebenzisa imithetho elula.
Ngokwenza, le migaqo ayisoloko ifanelekile kwimveliso, ngoko unokutshintsha inani leenkqubo zabasebenzi kwitheyibhile ethile: ALTER TABLE ... SET (parallel_workers = N).
Kutheni ukusetyenzwa ngokunxuseneyo kungasetyenziswanga?
Ukongeza kuluhlu olude lwezithintelo, kukwakho nokuhlolwa kweendleko:
- ukuphepha ukusetyenzwa okufanayo kwezicelo ezimfutshane. Le parameter iqikelela ixesha lokulungiselela imemori, ukuqala inkqubo, kunye nokutshintshiselana kwedatha yokuqala.
: unxibelelwano phakathi kwenkokeli kunye nabasebenzi banokulibaziseka ngokulingana nenani lee-tuples ezivela kwiinkqubo zomsebenzi. Le parameter ibala ixabiso lotshintshiselwano lwedatha.
Nested Loop Joins
PostgreSQL 9.6+ может выполнять вложенные циклы параллельно — это простая операция.
explain (costs off) select c_custkey, count(o_orderkey)
from customer left outer join orders on
c_custkey = o_custkey and o_comment not like '%special%deposits%'
group by c_custkey;
QUERY PLAN
--------------------------------------------------------------------------------------
Finalize GroupAggregate
Group Key: customer.c_custkey
-> Gather Merge
Workers Planned: 4
-> Partial GroupAggregate
Group Key: customer.c_custkey
-> Nested Loop Left Join
-> Parallel Index Only Scan using customer_pkey on customer
-> Index Scan using idx_orders_custkey on orders
Index Cond: (customer.c_custkey = o_custkey)
Filter: ((o_comment)::text !~~ '%special%deposits%'::text)Ingqokelela yenzeka kwinqanaba lokugqibela, ngoko ke i-Nested Loop Ekhohlo Joyina ngumsebenzi ofanayo. ISalathisi Esinxuseneyo Kuphela Skena saziswa kuphela kuguqulelo lwe-10. Sisebenza ngokufana ne-parallel serial scanning. Imeko c_custkey = o_custkey ifunda iodolo enye ngomtya womxhasi ngamnye. Ngoko ke ayihambelani.
Hash Joyina
Inkqubo nganye yabasebenzi idala itafile yayo ye-hash kude kube yi-PostgreSQL 11. Kwaye ukuba kukho ngaphezu kwezine zezi nkqubo, ukusebenza akuyi kuphucula. Kwinguqulelo entsha, itafile ye-hash yabelwana ngayo. Inkqubo nganye yomsebenzi inokusebenzisa i-WORK_MEM ukwenza itafile ye-hash.
select
l_shipmode,
sum(case
when o_orderpriority = '1-URGENT'
or o_orderpriority = '2-HIGH'
then 1
else 0
end) as high_line_count,
sum(case
when o_orderpriority <> '1-URGENT'
and o_orderpriority <> '2-HIGH'
then 1
else 0
end) as low_line_count
from
orders,
lineitem
where
o_orderkey = l_orderkey
and l_shipmode in ('MAIL', 'AIR')
and l_commitdate < l_receiptdate
and l_shipdate < l_commitdate
and l_receiptdate >= date '1996-01-01'
and l_receiptdate < date '1996-01-01' + interval '1' year
group by
l_shipmode
order by
l_shipmode
LIMIT 1;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=1964755.66..1964961.44 rows=1 width=27) (actual time=7579.592..7922.997 rows=1 loops=1)
-> Finalize GroupAggregate (cost=1964755.66..1966196.11 rows=7 width=27) (actual time=7579.590..7579.591 rows=1 loops=1)
Group Key: lineitem.l_shipmode
-> Gather Merge (cost=1964755.66..1966195.83 rows=28 width=27) (actual time=7559.593..7922.319 rows=6 loops=1)
Workers Planned: 4
Workers Launched: 4
-> Partial GroupAggregate (cost=1963755.61..1965192.44 rows=7 width=27) (actual time=7548.103..7564.592 rows=2 loops=5)
Group Key: lineitem.l_shipmode
-> Sort (cost=1963755.61..1963935.20 rows=71838 width=27) (actual time=7530.280..7539.688 rows=62519 loops=5)
Sort Key: lineitem.l_shipmode
Sort Method: external merge Disk: 2304kB
Worker 0: Sort Method: external merge Disk: 2064kB
Worker 1: Sort Method: external merge Disk: 2384kB
Worker 2: Sort Method: external merge Disk: 2264kB
Worker 3: Sort Method: external merge Disk: 2336kB
-> Parallel Hash Join (cost=382571.01..1957960.99 rows=71838 width=27) (actual time=7036.917..7499.692 rows=62519 loops=5)
Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
-> Parallel Seq Scan on lineitem (cost=0.00..1552386.40 rows=71838 width=19) (actual time=0.583..4901.063 rows=62519 loops=5)
Filter: ((l_shipmode = ANY ('{MAIL,AIR}'::bpchar[])) AND (l_commitdate < l_receiptdate) AND (l_shipdate < l_commitdate) AND (l_receiptdate >= '1996-01-01'::date) AND (l_receiptdate < '1997-01-01 00:00:00'::timestamp without time zone))
Rows Removed by Filter: 11934691
-> Parallel Hash (cost=313722.45..313722.45 rows=3750045 width=20) (actual time=2011.518..2011.518 rows=3000000 loops=5)
Buckets: 65536 Batches: 256 Memory Usage: 3840kB
-> Parallel Seq Scan on orders (cost=0.00..313722.45 rows=3750045 width=20) (actual time=0.029..995.948 rows=3000000 loops=5)
Planning Time: 0.977 ms
Execution Time: 7923.770 msUmbuzo we-12 ovela kwi-TPC-H ubonisa ngokucacileyo uxhulumaniso lwe-hash oluhambelanayo. Inkqubo nganye yabasebenzi inegalelo ekudalweni kwetafile yehashi eqhelekileyo.
Dibanisa Joyina
Udibaniso lokudibanisa aludibanisi kwindalo. Sukuba nexhala ukuba eli linyathelo lokugqibela lombuzo- usengaqhuba ngokunxuseneyo.
-- Query 2 from TPC-H
explain (costs off) select s_acctbal, s_name, n_name, p_partkey, p_mfgr, s_address, s_phone, s_comment
from part, supplier, partsupp, nation, region
where
p_partkey = ps_partkey
and s_suppkey = ps_suppkey
and p_size = 36
and p_type like '%BRASS'
and s_nationkey = n_nationkey
and n_regionkey = r_regionkey
and r_name = 'AMERICA'
and ps_supplycost = (
select
min(ps_supplycost)
from partsupp, supplier, nation, region
where
p_partkey = ps_partkey
and s_suppkey = ps_suppkey
and s_nationkey = n_nationkey
and n_regionkey = r_regionkey
and r_name = 'AMERICA'
)
order by s_acctbal desc, n_name, s_name, p_partkey
LIMIT 100;
QUERY PLAN
----------------------------------------------------------------------------------------------------------
Limit
-> Sort
Sort Key: supplier.s_acctbal DESC, nation.n_name, supplier.s_name, part.p_partkey
-> Merge Join
Merge Cond: (part.p_partkey = partsupp.ps_partkey)
Join Filter: (partsupp.ps_supplycost = (SubPlan 1))
-> Gather Merge
Workers Planned: 4
-> Parallel Index Scan using <strong>part_pkey</strong> on part
Filter: (((p_type)::text ~~ '%BRASS'::text) AND (p_size = 36))
-> Materialize
-> Sort
Sort Key: partsupp.ps_partkey
-> Nested Loop
-> Nested Loop
Join Filter: (nation.n_regionkey = region.r_regionkey)
-> Seq Scan on region
Filter: (r_name = 'AMERICA'::bpchar)
-> Hash Join
Hash Cond: (supplier.s_nationkey = nation.n_nationkey)
-> Seq Scan on supplier
-> Hash
-> Seq Scan on nation
-> Index Scan using idx_partsupp_suppkey on partsupp
Index Cond: (ps_suppkey = supplier.s_suppkey)
SubPlan 1
-> Aggregate
-> Nested Loop
Join Filter: (nation_1.n_regionkey = region_1.r_regionkey)
-> Seq Scan on region region_1
Filter: (r_name = 'AMERICA'::bpchar)
-> Nested Loop
-> Nested Loop
-> Index Scan using idx_partsupp_partkey on partsupp partsupp_1
Index Cond: (part.p_partkey = ps_partkey)
-> Index Scan using supplier_pkey on supplier supplier_1
Index Cond: (s_suppkey = partsupp_1.ps_suppkey)
-> Index Scan using nation_pkey on nation nation_1
Index Cond: (n_nationkey = supplier_1.s_nationkey)Indawo ethi "Hlanganisa Joyina" ibekwe ngentla ko "Hlanganisa ukudibanisa". Ngoko ke ukudibanisa akusebenzisi ukuqhubekeka ngokuhambelanayo. Kodwa indawo ethi "Parallel Index Scan" isanceda kwicandelo part_pkey.
Uqhagamshelwano ngamacandelo
KwiPostgreSQL 11 ikhubazwe ngokungagqibekanga: inocwangciso olubiza kakhulu. Iitheyibhile ezinezahlulo ezifanayo zinokudityaniswa isahlulo ngokwahlulahlula. Ngale ndlela iiPostgres ziya kusebenzisa iitafile ezincinci zehashi. Uxhulumaniso ngalunye lwamacandelo lunokuhambelana.
tpch=# set enable_partitionwise_join=t;
tpch=# explain (costs off) select * from prt1 t1, prt2 t2
where t1.a = t2.b and t1.b = 0 and t2.b between 0 and 10000;
QUERY PLAN
---------------------------------------------------
Append
-> Hash Join
Hash Cond: (t2.b = t1.a)
-> Seq Scan on prt2_p1 t2
Filter: ((b >= 0) AND (b <= 10000))
-> Hash
-> Seq Scan on prt1_p1 t1
Filter: (b = 0)
-> Hash Join
Hash Cond: (t2_1.b = t1_1.a)
-> Seq Scan on prt2_p2 t2_1
Filter: ((b >= 0) AND (b <= 10000))
-> Hash
-> Seq Scan on prt1_p2 t1_1
Filter: (b = 0)
tpch=# set parallel_setup_cost = 1;
tpch=# set parallel_tuple_cost = 0.01;
tpch=# explain (costs off) select * from prt1 t1, prt2 t2
where t1.a = t2.b and t1.b = 0 and t2.b between 0 and 10000;
QUERY PLAN
-----------------------------------------------------------
Gather
Workers Planned: 4
-> Parallel Append
-> Parallel Hash Join
Hash Cond: (t2_1.b = t1_1.a)
-> Parallel Seq Scan on prt2_p2 t2_1
Filter: ((b >= 0) AND (b <= 10000))
-> Parallel Hash
-> Parallel Seq Scan on prt1_p2 t1_1
Filter: (b = 0)
-> Parallel Hash Join
Hash Cond: (t2.b = t1.a)
-> Parallel Seq Scan on prt2_p1 t2
Filter: ((b >= 0) AND (b <= 10000))
-> Parallel Hash
-> Parallel Seq Scan on prt1_p1 t1
Filter: (b = 0)Into ephambili kukuba uxhulumaniso kumacandelo luhambelana kuphela ukuba la macandelo makhulu ngokwaneleyo.
Fanayo iFakelo
ingasetyenziswa endaweni yeebhloko ezahlukeneyo kuhambo lomsebenzi olwahlukeneyo. Oku kuqhele ukwenzeka nge-UNION YONKE imibuzo. Ukungalungi kukunxulunyaniswa okuncinci, kuba inkqubo yomsebenzi ngamnye yenza kuphela isicelo esi-1.
Kukho iinkqubo zabasebenzi ezi-2 ezisebenzayo apha, nangona ezi-4 zivuliwe.
tpch=# explain (costs off) select sum(l_quantity) as sum_qty from lineitem where l_shipdate <= date '1998-12-01' - interval '105' day union all select sum(l_quantity) as sum_qty from lineitem where l_shipdate <= date '2000-12-01' - interval '105' day;
QUERY PLAN
------------------------------------------------------------------------------------------------
Gather
Workers Planned: 2
-> Parallel Append
-> Aggregate
-> Seq Scan on lineitem
Filter: (l_shipdate <= '2000-08-18 00:00:00'::timestamp without time zone)
-> Aggregate
-> Seq Scan on lineitem lineitem_1
Filter: (l_shipdate <= '1998-08-18 00:00:00'::timestamp without time zone)Iinguqu ezibaluleke kakhulu
- WORK_MEM inciphisa inkumbulo ngenkqubo nganye, hayi imibuzo nje: work_mem iinkqubo unxibelelwano = inkumbulo eninzi.
- - zingaphi iinkqubo zabasebenzi eziya kusetyenziselwa inkqubo ehambelanayo kwisicwangciso.
- - ukulungelelanisa inani elipheleleyo leenkqubo zabasebenzi kwinani le-CPU cores kwiseva.
- - okufanayo, kodwa kwiinkqubo zomsebenzi ezifanayo.
Iziphumo
Ukusukela kwinguqulelo 9.6, ukusetyenzwa ngokunxuseneyo kunokuphucula kakhulu ukusebenza kwemibuzo entsonkothileyo eskena imiqolo emininzi okanye izalathisi. Kwi-PostgreSQL 10, ukusetyenzwa okufanayo kunikwe amandla ngokungagqibekanga. Khumbula ukuyivala kwiiseva ezinomthwalo omkhulu we-OLTP. Ukuskena okulandelelanayo okanye ukuskena kwesalathisi kudla izixhobo ezininzi. Ukuba awusebenzisi ngxelo kuyo yonke idataset, ungaphucula umsebenzi wombuzo ngokongeza ngokulula izalathisi ezilahlekileyo okanye usebenzisa ulwahlulelo olululo.
iimbekiselo
umthombo: www.habr.com