Hi,
our setup:
Postgres server is running on CentOS release 6.10 (Final) instance.
Server Version is PostgreSQL 9.5.9 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18), 64-bit
With the following parameters set:
wal_level = 'logical' # replica < logical
max_replication_slots = 10
max_wal_senders = 10
track_commit_timestamp = on
We are using decoder_raw module for retrieving/read the WAL data through the logical decoding mechanism.
Application setup:
The actual TCapture engine is a Java application which runs as a separate program outside Postgres, and which must be started explicitly.
When TCapture is running, it will scan the transaction log (with TCapt module) of all primary databases and pick up transactions which must be replicated.
Transactions which have been picked up are stored in the “Replication Database”, a PG user database exclusively used by TCapture.
In the Replication Database, transaction is ‘copied’ to all replicate databases which have a subscription for this transaction.
Transaction is then applied to the replicate tables by inserting it into by the dedicated Java application module
We runs TCapt module in the loop for reading a primary database which is a documental database (with binary columns) .
Behavior reported (Bug)
We have TCapture Replication Server running for successfully for weeks but recently we encountered following error:
cat log/TCapture_enodp_2021-04-12-11\:30\:16_err.log
org.postgresql.util.PSQLException: ERROR: got sequence entry 258 for toast chunk 538757697 instead of seq 0
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2553)
at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(QueryExecutorImpl.java:1212)
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1112)
at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImpl.java:44)
at org.postgresql.core.v3.replication.V3PGReplicationStream.receiveNextData(V3PGReplicationStream.java:160)
at org.postgresql.core.v3.replication.V3PGReplicationStream.readInternal(V3PGReplicationStream.java:125)
at org.postgresql.core.v3.replication.V3PGReplicationStream.readPending(V3PGReplicationStream.java:82)
at com.edslab.TCapt.receiveChangesOccursBeforTCapt(TCapt.java:421)
at com.edslab.TCapt.run(TCapt.java:182)
at java.lang.Thread.run(Thread.java:745)
After restarting our TCapt module (see
https://www.tcapture.net/ for better understand the project TCapture), the error went away. But this causes the producer module (Tapt) to shut down.
Please note that we run TCapture with other Postgres versions (9.6, 10, 11,ec..) without problems !!
Is there any resolution for this issue or is it resolved in the higher version of postgres?
Regards,
Silvio
