Could not read() message from seqserver

Products

• VMware Tanzu Greenplum

Issue/Introduction

Symptoms:
Error: Could not read() message from seqserver.(error:104). Closing connection. (seqserver.c:284)

Environment

Cause

The segment request to sequence server on master times out waiting for a sequence response. This will happen usually when many sequence requests are made.

Resolution

Update the sequence's "cache_value". A value of "1" in "cache_value" means it caches one sequence for each request to the sequence server. By increasing "cache_value" you're limiting the number of sequence requests sent to master. 

Check sequence cache_value (seq_test)

select * from xref.seq_test;
     sequence_name     |     last_value      | increment_by |      max_value      |      min_value      | cache_value | log_cnt | is_cycled | is_called
-----------------------+---------------------+--------------+---------------------+---------------------+-------------+---------+-----------+-----------
 seq_test              | 2100000004040261379 |            1 | 2199999999999999999 | 2100000000000000001 |           1 |      15 | f         | t

Change the sequence's cache_value (to 100)

ALTER SEQUENCE xref.seq_test CACHE 100