For a specific task request handler I'm observing elevated TransactionFailedError (too much contention) while *reading* certain entity-groups inside cross-group transactions (GAE Standard, Python 2.7, NDB). In almost all cases, the error message will blame either of two entity-groups, which are read-only inside the transaction. Moreover, there had been no write-ops at all to these entity-groups for a long time, so I'm 100% certain, there was no other request that tried or performed a write op to these two entity groups, which could cause version conflicts. (More details on StackOverflow <http://stackoverflow.com/questions/43528357/transactionfailederror-too-much-contention-when-reading-cross-group-entit> )
I understand the concept of entity-groups, that there is no guarantee for exceeding 1 write-op per second per entity group, and that there is a max of 25 entity groups possible inside an xg transaction (and 5 transactional tasks can be added at most). But somehow, it seems that I miss something. Is there also a read limitation inside transactions or something else that would explain why getting an entity from Datastore would raise this error? -- HATZIS Edelstahlbearbeitung GmbH Hojen 2 87490 Haldenwang (Allgäu) Germany Handelsregister Kempten (Allgäu): HRB 4204 Geschäftsführer: Paulos Hatzis, Charalampos Hatzis Umsatzsteuer-Identifikationsnummer: DE 128791802 http://www.hatzis.de/ -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to google-appengine@googlegroups.com. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/b629f650-2234-4da6-b586-c7429436d9dd%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
