Failed: R2dbcTimestampOffsetProjectionSpec

[johanandren]

https://github.com/akka/akka-projection/actions/runs/4960317517/jobs/8875638925?pr=894#step:7:733

Full logs:
logs_7046.zip

[johanandren]

H2: https://github.com/akka/akka-projection/actions/runs/5374660220/jobs/9750279843#step:6:834

[info] - must be able to skip envelopes but still store offset *** FAILED *** (10 seconds, 102 milliseconds)
[info]   The code passed to eventually never returned normally. Attempted 106 times over 10.053910014000001 seconds. Last failure message: None was not equal to Some(TimestampOffset(2023-06-26T06:44:20.923647Z, 1970-01-01T00:00:00Z, Map("b92dec93-793f-42cc-9537-ea79f6ace0f6" -> 6))). (R2dbcTimestampOffsetProjectionSpec.scala:1030)
[info]   org.scalatest.exceptions.TestFailedDueToTimeoutException:
[info]   at org.scalatest.enablers.Retrying$$anon$4.tryTryAgain$2(Retrying.scala:219)
[info]   at org.scalatest.enablers.Retrying$$anon$4.retry(Retrying.scala:226)
[info]   at org.scalatest.concurrent.Eventually.eventually(Eventually.scala:415)
[info]   at org.scalatest.concurrent.Eventually.eventually$(Eventually.scala:414)
[info]   at akka.actor.testkit.typed.scaladsl.ScalaTestWithActorTestKit.eventually(ScalaTestWithActorTestKit.scala:31)
[info]   at akka.projection.r2dbc.R2dbcTimestampOffsetProjectionSpec.$anonfun$new$97(R2dbcTimestampOffsetProjectionSpec.scala:1030)

[johanandren]

https://github.com/akka/akka-projection/actions/runs/5390973258/jobs/9787124185?pr=932#step:6:551

[johanandren]

https://github.com/akka/akka-projection/actions/runs/5446031156/jobs/9906168563?pr=932#step:6:309

[pvlugter]

https://github.com/akka/akka-projection/actions/runs/6462610261/job/17544495042#step:6:836

[xeppaka]

Hi, we recently faced a problem with long DB queries and I think it's related to that issue.
We have an app with small amount of entities (which results in small amount of slices) in the database. When projection makes a request for a range of slices where no entity exist yet, it uses db_timestamp >= '1970-01-01 00:00:00+00'::timestamp with time zone in a query and offset is not saved after that query. When other slice ranges becomes bigger in terms of saved events the query becomes longer because index is not used (I'm not sure why and details about that). Here is the report from Postgres for long query (8034.857 ms):

2024-01-09 13:34:58 UTC:10.0.6.239(40998):accounts_app1@accounts:[4133]:LOG:  duration: 8034.857 ms  plan:
	Query Text: SELECT slice, persistence_id, seq_nr, db_timestamp, CURRENT_TIMESTAMP AS read_db_timestamp, tags, event_ser_id, event_ser_manifest, event_payload, meta_ser_id, meta_ser_manifest, meta_payload FROM event_journal WHERE entity_type = $1 AND slice in (128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255) AND db_timestamp >= $2  AND db_timestamp < CURRENT_TIMESTAMP - interval '100 milliseconds' AND deleted = false ORDER BY db_timestamp, seq_nr LIMIT $3
	Limit  (cost=177909.06..178025.74 rows=1000 width=1008)
	  ->  Gather Merge  (cost=177909.06..193820.47 rows=136374 width=1008)
	        Workers Planned: 2
	        ->  Sort  (cost=176909.04..177079.51 rows=68187 width=1008)
	              Sort Key: db_timestamp, seq_nr
	              ->  Parallel Seq Scan on event_journal  (cost=0.32..173170.42 rows=68187 width=1008)
	                    Filter: ((NOT deleted) AND (db_timestamp >= '1970-01-01 00:00:00+00'::timestamp with time zone) AND ((entity_type)::text = 'TransactionCore'::text) AND (slice = ANY ('{128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255}'::integer[])) AND (db_timestamp < (CURRENT_TIMESTAMP - '00:00:00.1'::interval)))

For the query above no offset were saved and no entities exist in the slice range 128 to 255.

[johanandren]

FYI I've broken that out into a separate issue @xeppaka