Use transactions in Hybris if you care about performance

Posted on by admin

In my career, I participated in several projects that are based on the Hybris e-commerce platform. I wrote tons of Hybris code and read a lot more of other’s code. There is one thing that is common to all Hybris projects that I dealt with – transactions are used very occasionally. In most cases it is the out-of-the-box code and, more rarely, it is code where transactions are apparently necessary and unavoidable, e.g. stock update. The vast majority of the project code does not use transactions at all. It could seem to be a disaster because none of the A.C.I.D. principles is guaranteed, but surprisingly, these projects are in “live” and are used more or less successfully with respect to business needs. You can ask ‘why?’.

Well, I think that it is mostly because data that is modified actively belong to one of these groups:

  • data that does not suffer from non-atomic updates (e.g. product data) or is being rewritten regularly from external feeds so that errors do not accumulate;
  • data that is attached to a single user session naturally (cart, customer profile, order) and the user does not force data races in regular use.

So, (almost) nobody uses transactions for data integrity in Hybris and applications still work fine in most cases in production – why should we care about transactions at all? There are at least two reasons for this. First, there is a huge difference between code that does not corrupt data in most cases and code that does not corrupt data in all possible cases. It should be clear for developers whoever spent hours or days in troubleshooting a mysterious problem that nobody knew how did it happen. Second, it greatly improves the performance of the Hybris code. Let’s look into this aspect in more detail.

Many Hybris developers think that transactions are slow and error-prone, because tables and/or table rows can be locked within a transaction; there is overhead on keeping the transaction state. And, the worse, many developers believe so just because other developers tell them that transactions are slow. What do we have in reality? These are myths that are easily dispelled by the fact that when there is no explicit transaction started by the developer each persistence operation is conducted in its own transaction (i.e. in the auto-commit mode). So runtime is full of transactions!

Let’s consider a simple example when a new item is added to the shopping cart.

final CartModificationData cartModification = cartFacade.addToCart(code, qty);

This line is simple and self-explained. The out-of-the-fox cart facade is used here and is run by the out-of-the-box AddToCartController outside a transaction. Let’s look what calls to the DB this line produces:

  1. SELECT PK FROM cartentries item_t0 WHERE (( item_t0.p_entrynumber = 0 AND  
item_t0.p_order  = 8796093087787 )) AND 
(item_t0.TypePkString=8796098363474 )
  2. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order  =
8796093087787) AND (item_t0.TypePkString=8796098363474 ) order by 
item_t0.p_entrynumber  ASC
  3. INSERT INTO cartentries
( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_baseprice,p_calculated,p_entrynumber,p_giveaway,p_info,p_order,p_product,p_quantity,p_rejected,p_taxvaluesinternal,p_totalprice,p_unit ) 
VALUES (0,8796093120556,'2019-04-15 17:26:34.583','2019-04-15 17:26:34.583',8796098363474,0.0,0,0,0,'product "816802" with name "Cyber-shot W55"',8796093087787,8796231958529,1,0,'[]',0.0,8796093054986)
  4. SELECT * FROM cartentries WHERE PK='8796093120556'
  5. SELECT * FROM props WHERE ITEMPK='8796093120556'
  6. INSERT INTO cartentries44sn (itempk, itemtypepk, timestamp, currenttimestamp, changinguser, payloadbefore, payloadafter, operationtype, context) 
VALUES ('8796093120556', '8796098363474', '2019-04-15 17:26:34.583', '2019-04-15 17:26:34.587', 'anonymous', '{"mapBasedAttributes":{},"attributes":{},"locAttributes":{}}', '{"mapBasedAttributes":{},"attributes":{"product":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796231958529"]},"quantity":{"type":{"type":"java.lang.Long","collection":""},"value":["1"]},"rejected":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"entrynumber":{"type":{"type":"java.lang.Integer","collection":""},"value":["0"]},"taxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"baseprice":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"unit":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093054986"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394583"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796098363474"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394583"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120556"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"giveaway":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"info":{"type":{"type":"java.lang.String","collection":""},"value":["product \"816802\" with name \"Cyber-shot W55\""]},"order":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]}},"locAttributes":{}}', '1', '{}')
  7. commit
  8. SELECT * FROM cartentries WHERE PK=8796093120556
  9. SELECT * FROM composedtypes WHERE jaloClassName = 'de.hybris.platform.jalo.product.Unit'
  10. SELECT PK FROM units item_t0 WHERE ( item_t0.p_unittype ='pieces' 
AND  item_t0.PK <>8796093054986) AND (item_t0.TypePkString=8796098003026 )
  11. SELECT x.col_PK FROM (SELECT  item_t0.PK  AS col_PK FROM discountrows item_t0 WHERE 
( item_t0.p_productmatchqualifier  in (0, 8796231958529) and  item_t0.p_usermatchqualifier  in (0, 8796093087748)) 
AND (item_t0.TypePkString=8796111142994 AND ((   item_t0.p_product  IS NOT NULL OR item_t0.p_catalogversion  
IS NULL OR  item_t0.p_catalogversion  IN (8796093350489,8796093383257,8796093448793) ))) 
UNION SELECT  item_t1.PK  AS col_PK FROM discountrows item_t1 WHERE ( item_t1.p_productmatchqualifier =-1 and  
item_t1.p_productid ='816802' and  item_t1.p_usermatchqualifier  in (0, 8796093087748)) 
AND (item_t1.TypePkString=8796111142994 AND ((   item_t1.p_product  IS NOT NULL OR item_t1.p_catalogversion  IS NULL OR  
item_t1.p_catalogversion  IN (8796093350489,8796093383257,8796093448793) )))) x
  12. SELECT * FROM cartentries WHERE PK='8796093120556'
  13. SELECT * FROM props WHERE ITEMPK='8796093120556'
  14. UPDATE cartentries SET hjmpTS = 1 ,modifiedTS='2019-04-15 17:26:34.631',p_baseprice=260.87,p_calculated=1,
p_discountvaluesinternal='[]',p_taxvaluesinternal='[<TV<jp-vat-full#5.0#false#12.42#USD>VT>]',p_totalprice=260.87 
WHERE PK = 8796093120556 AND (sealed IS NULL OR sealed=0)
  15. SELECT * FROM cartentries WHERE PK='8796093120556'
  16. SELECT * FROM props WHERE ITEMPK='8796093120556'
  17. INSERT INTO cartentries44sn (itempk, itemtypepk, timestamp, currenttimestamp, changinguser, payloadbefore, payloadafter, operationtype, context) 
VALUES ('8796093120556', '8796098363474', '2019-04-15 17:26:34.631', '2019-04-15 17:26:34.633', 'anonymous', '{"mapBasedAttributes":{},"attributes":{"product":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796231958529"]},"quantity":{"type":{"type":"java.lang.Long","collection":""},"value":["1"]},"rejected":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"entrynumber":{"type":{"type":"java.lang.Integer","collection":""},"value":["0"]},"taxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"baseprice":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"unit":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093054986"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394583"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796098363474"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394583"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120556"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"giveaway":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"info":{"type":{"type":"java.lang.String","collection":""},"value":["product \"816802\" with name \"Cyber-shot W55\""]},"order":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]}},"locAttributes":{}}', '{"mapBasedAttributes":{},"attributes":{"product":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796231958529"]},"quantity":{"type":{"type":"java.lang.Long","collection":""},"value":["1"]},"rejected":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"entrynumber":{"type":{"type":"java.lang.Integer","collection":""},"value":["0"]},"taxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#12.42#USD>VT>]"]},"baseprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"unit":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093054986"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394631"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796098363474"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394583"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120556"]},"discountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["true"]},"giveaway":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"info":{"type":{"type":"java.lang.String","collection":""},"value":["product \"816802\" with name \"Cyber-shot W55\""]},"order":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]}},"locAttributes":{}}', '2', '{}')
  18. commit
  19. SELECT * FROM cartentries WHERE PK=8796093120556
  20. commit
  21. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order =8796093087787) 
AND (item_t0.TypePkString=8796098363474 ) order by  item_t0.p_entrynumber  ASC, item_t0.createdTS  ASC
  22. SELECT * FROM carts WHERE PK='8796093087787'
  23. SELECT * FROM props WHERE ITEMPK='8796093087787'
  24. UPDATE carts SET hjmpTS = 7 ,modifiedTS='2019-04-15 17:26:34.639',p_subtotal=260.87,p_totalprice=260.87,p_totaltax=12.42,
p_totaltaxvaluesinternal='[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]' 
WHERE PK = 8796093087787 AND (sealed IS NULL OR sealed=0)
  25. SELECT * FROM carts WHERE PK='8796093087787'
  26. SELECT * FROM props WHERE ITEMPK='8796093087787'
  27. INSERT INTO carts43sn (itempk, itemtypepk, timestamp, currenttimestamp, changinguser, payloadbefore, payloadafter, operationtype, context) 
VALUES ('8796093087787', '8796094038098', '2019-04-15 17:26:34.639', '2019-04-15 17:26:34.64', 'anonymous', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#11.47#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338365115"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["true"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["12.42"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394639"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["true"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '2', '{}')
  28. commit
  29. SELECT * FROM carts WHERE PK=8796093087787
  30. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order =8796093087787) AND 
(item_t0.TypePkString=8796098363474 ) order by  item_t0.p_entrynumber  ASC, item_t0.createdTS  ASC
  31. commit
  32. commit
  33. commit
  34. SELECT PK FROM catver2rulescontext item_t0 WHERE ( item_t0.p_catalogversion  IN (8796093350489)) 
AND (item_t0.TypePkString=8796115992658 )
  35. SELECT PK FROM campaign item_t0 WHERE ( item_t0.p_enabled  = 1 AND ( item_t0.p_startdate  IS NULL OR  
item_t0.p_startdate  <= '2019-04-15 17:26:34.649') AND ( item_t0.p_enddate  IS NULL OR  
item_t0.p_enddate  >= '2019-04-15 17:26:34.649')) AND (item_t0.TypePkString=8796118188114 )
  36. SELECT * FROM attributedescriptors WHERE EnclosingTypePK=8796093382738
  37. SELECT PK FROM carts item_t0 WHERE ( item_t0.p_code ='00000001') AND (item_t0.TypePkString=8796094038098 ) 
UNION ALL SELECT  item_t0.PK  FROM orders item_t0 WHERE ( item_t0.p_code ='00000001') 
AND (item_t0.TypePkString IN  (8796097609810,8796097675346,8796094169170) ) 
UNION ALL SELECT  item_t0.PK  FROM quotes item_t0 WHERE ( item_t0.p_code ='00000001') AND (item_t0.TypePkString=8796094103634 )
  38. SELECT PK FROM enginerules item_t0 JOIN droolskiebase item_t1 ON  item_t0.p_kiebase  =  item_t1.PK  JOIN rulesmodule item_t2 
ON  item_t1.p_kiemodule  =  item_t2.PK  WHERE ( item_t2.p_name  = 'promotions-module' AND  item_t0.p_code  = 'order_threshold_fixed_discount') 
AND ((item_t0.TypePkString=8796115566674  AND item_t1.TypePkString=8796115599442  
AND item_t2.TypePkString=8796115697746 ))
  39. SELECT * FROM attributedescriptors WHERE EnclosingTypePK=8796115566674
  40. INSERT INTO promotionresult ( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_certainty,p_order,p_promotion ) 
VALUES (0,8796093191061,'2019-04-15 17:26:34.67','2019-04-15 17:26:34.67',8796113731666,'1.0',8796093087787,8796094108562)
  41. SELECT PK FROM orderentryconsumed item_t0 WHERE ( item_t0.p_promotionresult  = 8796093191061) 
AND (item_t0.TypePkString=8796114485330 )
  42. SELECT * FROM promotionresultlp WHERE ITEMPK=8796093191061 AND LANGPK=8796093055008
  43. INSERT INTO promotionresultlp ( p_messagefired,ITEMPK,ITEMTYPEPK,LANGPK ) 
VALUES ( 'Buy over $200.00 get $20.00 discount on cart',8796093191061,8796113731666,8796093055008 )
  44. UPDATE promotionresult SET hjmpTS = 1 ,modifiedTS='2019-04-15 17:26:34.672',p_moduleversion=23,p_ordercode='00000001',p_ruleversion=22,p_rulesmodulename='promotions-module' 
WHERE PK = 8796093191061 AND (sealed IS NULL OR sealed=0)
  45. commit
  46. SELECT * FROM promotionresult WHERE PK=8796093191061
  47. INSERT INTO promotionaction ( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_amoun0,p_guid,p_markedapplied,p_promotionresult,p_rule,p_strategyid ) 
VALUES (0,8796093191063,'2019-04-15 17:26:34.675','2019-04-15 17:26:34.675',8796114288722,'20.00000','Action[ef172776-a299-4c09-b98d-071c3c38a6f3]',1,8796093191061,8796093748204,'defaultOrderAdjustTotalActionStrategy')
  48. commit
  49. SELECT * FROM promotionaction WHERE PK=8796093191063
  50. SELECT * FROM carts WHERE PK='8796093087787'
  51. SELECT * FROM props WHERE ITEMPK='8796093087787'
  52. UPDATE carts SET hjmpTS = 8 ,modifiedTS='2019-04-15 17:26:34.679',p_calculated=0,p_globaldiscountvaluesinternal='[<DV<Action[ef172776-a299-4c09-b98d-071c3c38a6f3]#20.0#true#0.0#USD#false>VD>]' 
WHERE PK = 8796093087787 AND (sealed IS NULL OR sealed=0)
  53. SELECT * FROM carts WHERE PK='8796093087787'
  54. SELECT * FROM props WHERE ITEMPK='8796093087787'
  55. INSERT INTO carts43sn (itempk, itemtypepk, timestamp, currenttimestamp, changinguser, payloadbefore, payloadafter, operationtype, context) 
VALUES ('8796093087787', '8796094038098', '2019-04-15 17:26:34.679', '2019-04-15 17:26:34.68', 'anonymous', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["12.42"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394639"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["true"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<DV<Action[ef172776-a299-4c09-b98d-071c3c38a6f3]#20.0#true#0.0#USD#false>VD>]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["12.42"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394679"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '2', '{}')
  56. commit
  57. SELECT * FROM carts WHERE PK=8796093087787
  58. commit
  59. commit
  60. SELECT * FROM carts WHERE PK='8796093087787'
  61. SELECT * FROM props WHERE ITEMPK='8796093087787'
  62. UPDATE carts SET hjmpTS = 9 ,modifiedTS='2019-04-15 17:26:34.686',p_calculated=1,p_globaldiscountvaluesinternal='[<DV<Action[ef172776-a299-4c09-b98d-071c3c38a6f3]#20.0#true#20.0#USD#false>VD>]',p_totaldiscounts=20.0,p_totalprice=240.87,p_totaltax=11.47,p_totaltaxvaluesinternal='[<TV<jp-vat-full#5.0#false#11.47#NULL>VT>]' 
WHERE PK = 8796093087787 AND (sealed IS NULL OR sealed=0)
  63. SELECT * FROM carts WHERE PK='8796093087787'
  64. SELECT * FROM props WHERE ITEMPK='8796093087787'
  65. INSERT INTO carts43sn (itempk, itemtypepk, timestamp, currenttimestamp, changinguser, payloadbefore, payloadafter, operationtype, context) 
VALUES ('8796093087787', '8796094038098', '2019-04-15 17:26:34.686', '2019-04-15 17:26:34.688', 'anonymous', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<DV<Action[ef172776-a299-4c09-b98d-071c3c38a6f3]#20.0#true#0.0#USD#false>VD>]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["12.42"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394679"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '{"mapBasedAttributes":{},"attributes":{"date":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"code":{"type":{"type":"java.lang.String","collection":""},"value":["00000001"]},"globaldiscountvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<DV<Action[ef172776-a299-4c09-b98d-071c3c38a6f3]#20.0#true#20.0#USD#false>VD>]"]},"paymentcost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"totalprice":{"type":{"type":"java.lang.Double","collection":""},"value":["240.87"]},"totaltaxvaluesinternal":{"type":{"type":"java.lang.String","collection":""},"value":["[<TV<jp-vat-full#5.0#false#11.47#NULL>VT>]"]},"discountsincludepaymentcost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"sessionid":{"type":{"type":"java.lang.String","collection":""},"value":["D366641C62BC856D467A4C07EF47C0D3"]},"store":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093122525"]},"deliverycost":{"type":{"type":"java.lang.Double","collection":""},"value":["0.0"]},"discountsincludedeliverycost":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"totaltax":{"type":{"type":"java.lang.Double","collection":""},"value":["11.47"]},"site":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093121576"]},"modifiedtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555338394686"]},"itemtype":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796094038098"]},"subtotal":{"type":{"type":"java.lang.Double","collection":""},"value":["260.87"]},"guid":{"type":{"type":"java.lang.String","collection":""},"value":["83e2f191-2720-4e10-a4e6-9ae1e83bf91a"]},"totaldiscounts":{"type":{"type":"java.lang.Double","collection":""},"value":["20.0"]},"currency":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093120545"]},"creationtime":{"type":{"type":"java.util.Date","collection":""},"value":["1555337984857"]},"pk":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087787"]},"net":{"type":{"type":"java.lang.Boolean","collection":""},"value":["false"]},"calculated":{"type":{"type":"java.lang.Boolean","collection":""},"value":["true"]},"user":{"type":{"type":"de.hybris.platform.core.PK","collection":""},"value":["8796093087748"]}},"locAttributes":{}}', '2', '{}')
  66. commit
  67. SELECT * FROM carts WHERE PK=8796093087787
  68. SELECT PK FROM abstrcfgproductinfo item_t0 WHERE ( item_t0.p_orderentry =8796093120556) 
AND (item_t0.TypePkString IN  (8796109766738,8796109701202) ) order by  item_t0.p_orderentrypos  ASC, item_t0.createdTS  ASC
  69. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093087795) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  70. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093153331) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  71. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093186099) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  72. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093218867) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  73. SELECT PK FROM commentitemrelations item_t0 JOIN comments item_t1 ON  item_t0.SourcePK = item_t1.PK  
WHERE ( item_t0.Qualifier  = 'CommentItemRelation' AND  item_t0.TargetPK  = 8796093120556 AND item_t0.languagepk  
IS NULL) AND (item_t1.TypePkString IN (8796112748626,8796112879698,8796112978002,8796112519250) ) 
order by item_t0.RSequenceNumber  ASC , item_t0.PK  ASC

There are 73 calls to the database in total! More interestingly, there are 13 ‘commit’ calls among them. Quite a number, isn’t it? ‘How could it happened?’ one can ask. Before we answer this question, let’s look into more details what is a persistence operation is for Hybris. To keep it simple, for a developer it is one of the following:

  • save() or modelService.saveAll() call, where each item is persisted individually
  • setter() call in the Jalo layer. Each Jalo setter invocation is an independent persistence operation that is instantly flushed to the database.
  • Outer transaction begin/commit boundary. When the outer transaction is committed all data that was modified inside this transaction is flushed to the database.

So, each commit from the listing above was triggered by one of these persistence operations. Can we improve this? Yes, we do. The answer is to wrap the operation into a transaction.

Note that inside a transaction things work slightly differently. In particular:

  • The so-called delayed store is introduced that accumulates all modifications of all items that are not saved.
  • Jalo item.setter() does not flush new value to the database. Instead, it puts it to the delayed store.
  • save() flushes item’s delayed store data to the database, but this modification is still a part of transaction non-committed data for the database and it can be rolled back.

As we see, transactions tend to group persistence operations and reduce the number of updates to the database, especially if Jalo is used. Therefore, we can expect that the number of calls to the database can be reduced when we wrap the code into a transaction.

It is nice and useful but it is not the full truth. The truth is that there is overhead induced by Hybris persistence layer on each item save. The following happens behind the scenes on each persistence operation:

  • Data is stored in the database.
  • Hybris invalidates the item’s cache entry. When you need this item again (even if it is the next line of the code) Hybris will retrieve it from the database again even if a tiny part of the item has been changed.
  • Hybris keeps track of the modification history for each item. There are special tables in the database creates with item tables that contain the difference between each persisted state of the item.

That’s where inefficiency hides that can be eliminated by using transactions. Recall the above-mentioned add to cart operation. Why did it produce so many calls to the database? First of all, because the cart model and the item model (and other models) are updated many times during this operation. It is not enough to just add a new cart item to the cart. You also need to recalculate cart total, apply for promotions, merge cart items if there are items that refer to the same SKU, etc. All this modifies models intensively and each modification is followed by a) model cache invalidation; b) updating model modification history, many and many times.

Well, it’s all theory, the reality can be different. Let’s check what calls Hybris issues to the database when the same operation is run into a transaction:

boolean success = false;
Transaction tx = Transaction.current();
tx.begin();
try {
       final CartModificationData cartModification = cartFacade.addToCart(code, qty);
       success = true;
} finally {
       if (success) {
             tx.commit();
       } else {
             tx.rollback();
       }
}

Here is the database call listing:

  1. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order =8796125823019) AND 
(item_t0.TypePkString=8796098363474 ) order by item_t0.p_entrynumber  ASC, item_t0.createdTS  ASC
  2. SELECT PK FROM cartentries item_t0 WHERE (( item_t0.p_entrynumber  = 0 AND  
item_t0.p_order  = 8796125823019 )) AND (item_t0.TypePkString=8796098363474 )
  3. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order  = 8796125823019) AND 
(item_t0.TypePkString=8796098363474 ) order by  item_t0.p_entrynumber  ASC
  4. INSERT INTO cartentries ( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_baseprice,p_calculated,p_entrynumber,p_giveaway,p_info,p_order,p_product,p_quantity,p_rejected,p_taxvaluesinternal,p_totalprice,p_unit ) 
VALUES (0,8796125855788,'2019-04-15 18:14:18.341','2019-04-15 18:14:18.341',8796098363474,0.0,0,0,0,'product "816802" with name "Cyber-shot W55"',8796125823019,8796231958529,1,0,'[]',0.0,8796093054986)
  5. UPDATE cartentries SET hjmpTS = 1 ,modifiedTS='2019-04-15 18:14:18.346',p_baseprice=260.87,p_calculated=1,p_discountvaluesinternal='[]',p_taxvaluesinternal='[<TV<jp-vat-full#5.0#false#12.42#USD>VT>]',p_totalprice=260.87 
WHERE PK = 8796125855788 AND (sealed IS NULL OR sealed=0)
  6. SELECT PK FROM cartentries item_t0 WHERE ( item_t0.p_order =8796125823019) AND 
(item_t0.TypePkString=8796098363474 ) order by  item_t0.p_entrynumber  ASC, item_t0.createdTS  ASC
  7. SELECT * FROM carts WHERE PK='8796125823019'
  8. SELECT * FROM props WHERE ITEMPK='8796125823019'
  9. UPDATE carts SET hjmpTS = 7 ,modifiedTS='2019-04-15 18:14:18.352',p_subtotal=260.87,p_totalprice=260.87,p_totaltax=12.42,p_totaltaxvaluesinternal='[<TV<jp-vat-full#5.0#false#12.42#NULL>VT>]' 
WHERE PK = 8796125823019 AND (sealed IS NULL OR sealed=0)
  10. SELECT PK FROM promotionresult item_t0 WHERE ( item_t0.p_order =8796125823019) AND 
(item_t0.TypePkString=8796113731666 ) order by  item_t0.createdTS  ASC
  11. SELECT PK FROM campaign item_t0 WHERE ( item_t0.p_enabled  = 1 AND ( item_t0.p_startdate  IS NULL OR  
item_t0.p_startdate  <= '2019-04-15 18:14:18.362') AND ( item_t0.p_enddate  IS NULL OR  
item_t0.p_enddate  >= '2019-04-15 18:14:18.362')) AND (item_t0.TypePkString=8796118188114 )
  12. SELECT PK FROM carts item_t0 WHERE ( item_t0.p_code ='00001000') AND (item_t0.TypePkString=8796094038098 ) 
UNION ALL SELECT  item_t0.PK  FROM orders item_t0 WHERE ( item_t0.p_code ='00001000') AND (item_t0.TypePkString IN  (8796097609810,8796097675346,8796094169170) ) 
UNION ALL SELECT  item_t0.PK  FROM quotes item_t0 WHERE ( item_t0.p_code ='00001000') AND (item_t0.TypePkString=8796094103634 )
  13. INSERT INTO promotionresult ( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_certainty,p_order,p_promotion ) 
VALUES (0,8796125860757,'2019-04-15 18:14:18.384','2019-04-15 18:14:18.384',8796113731666,'1.0',8796125823019,8796094108562)
  14. SELECT PK FROM orderentryconsumed item_t0 WHERE ( item_t0.p_promotionresult  = 8796125860757) 
AND (item_t0.TypePkString=8796114485330 )
  15. SELECT * FROM promotionresultlp WHERE ITEMPK=8796125860757 AND LANGPK=8796093055008
  16. INSERT INTO promotionresultlp ( p_messagefired,ITEMPK,ITEMTYPEPK,LANGPK ) 
VALUES ( 'Buy over $200.00 get $20.00 discount on cart',8796125860757,8796113731666,8796093055008 )
  17. UPDATE promotionresult SET hjmpTS = 1 ,modifiedTS='2019-04-15 18:14:18.388',p_moduleversion=23,p_ordercode='00001000',p_ruleversion=22,p_rulesmodulename='promotions-module' 
WHERE PK = 8796125860757 AND (sealed IS NULL OR sealed=0)
  18. INSERT INTO promotionaction ( hjmpTS,PK,createdTS,modifiedTS,TypePkString,p_amoun0,p_guid,p_markedapplied,p_promotionresult,p_rule,p_strategyid ) 
VALUES (0,8796125860759,'2019-04-15 18:14:18.391','2019-04-15 18:14:18.391',8796114288722,'20.00000','Action[20451b5f-2f56-44b5-98b2-f34d9c767aa3]',1,8796125860757,8796093748204,'defaultOrderAdjustTotalActionStrategy')
  19. UPDATE carts SET hjmpTS = 8 ,modifiedTS='2019-04-15 18:14:18.393',p_calculated=0,p_globaldiscountvaluesinternal='[<DV<Action[20451b5f-2f56-44b5-98b2-f34d9c767aa3]#20.0#true#0.0#USD#false>VD>]' 
WHERE PK = 8796125823019 AND (sealed IS NULL OR sealed=0)
  20. UPDATE carts SET hjmpTS = 9 ,modifiedTS='2019-04-15 18:14:18.397',p_calculated=1,p_globaldiscountvaluesinternal='[<DV<Action[20451b5f-2f56-44b5-98b2-f34d9c767aa3]#20.0#true#20.0#USD#false>VD>]',p_totaldiscounts=20.0,p_totalprice=240.87,p_totaltax=11.47,p_totaltaxvaluesinternal='[<TV<jp-vat-full#5.0#false#11.47#NULL>VT>]' 
WHERE PK = 8796125823019 AND (sealed IS NULL OR sealed=0)
  21. SELECT PK FROM abstrcfgproductinfo item_t0 WHERE ( item_t0.p_orderentry =8796125855788) AND 
(item_t0.TypePkString IN  (8796109766738,8796109701202) ) order by  item_t0.p_orderentrypos  ASC, item_t0.createdTS  ASC
  22. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093087795) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  23. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093153331) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  24. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093186099) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  25. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093186099) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  26. SELECT PK FROM medias item_t0 WHERE ( item_t0.p_mediacontainer  = 8796183887922 AND  item_t0.p_mediaformat  = 8796093218867) 
AND (item_t0.TypePkString IN  (8796100296786,8796100001874,8796100198482,8796099706962,8796100493394,8796099444818,8796099870802,8796100427858,8796099772498,8796099805266,8796100034642,8796100132946,8796099477586,8796099575890,8796099936338,8796099969106,8796100460626,8796100165714,8796099510354,8796099543122,8796099641426,8796099674194,8796093513810) )
  27. SELECT PK FROM commentitemrelations item_t0 JOIN comments item_t1 ON  item_t0.SourcePK = item_t1.PK  
WHERE ( item_t0.Qualifier  = 'CommentItemRelation' AND  item_t0.TargetPK  = 8796125855788 AND item_t0.languagepk  
IS NULL) AND (item_t1.TypePkString IN (8796112748626,8796112879698,8796112978002,8796112519250) ) 
order by item_t0.RSequenceNumber  ASC , item_t0.PK  ASC

As we see, the number of calls was reduced from 73 to just 26 and there are no commits at all. The data is committed when the transaction is committed explicitly.

It is easy to check how much time can be saved on executing a typical business operation inside a transaction compared to running it with no transaction. It depends on the operation and system load, but, to give an outline, during load testing sessions I saw that in most cases the same code runs 1.5-10 times faster inside a transaction. As a bonus, this code can become transactional, so that data inconsistency can be resolved inside a transaction and intermediate modification will not be visible outside the transaction.

Conclusion

Don’t be afraid of using a transaction in Hybris. Use them everywhere where you need to perform some data modifications atomically and/or be able to revert the modifications if something goes wrong. In many cases, this code will be not only more robust but also faster than its non-transactional alternative.