AMD FX 8120 / centos 6.2 / latest source (git head)
It seems to be quite easy to force a 'sync' replica to not be equal to master by recreating+loading a table in a while loop. For this test I compiled+checked+installed three separate instances on the same machine. The replica application_name are names 'wal_receiver_$copy' where $copy is 01, resp. 02. $ ./sync_state.sh pid | application_name | state | sync_state -------+------------------+-----------+------------ 19520 | wal_receiver_01 | streaming | sync 19567 | wal_receiver_02 | streaming | async (2 rows) port | synchronous_commit | synchronous_standby_names ------+--------------------+--------------------------- 6564 | on | wal_receiver_01 (1 row) port | synchronous_commit | synchronous_standby_names ------+--------------------+--------------------------- 6565 | off | (1 row) port | synchronous_commit | synchronous_standby_names ------+--------------------+--------------------------- 6566 | off | (1 row) The test consists of creating a table and loading tab-separated data from file with COPY and then taking the rowcount of that table (13 MB, almost 200k rows) in all three instances: # wget http://flybase.org/static_pages/downloads/FB2012_03/genes/fbgn_annotation_ID_fb_2012_03.tsv.gz slurp_file=fbgn_annotation_ID_fb_2012_03.tsv.gz zcat $slurp_file \ | grep -v '^#' \ | grep -Ev '^[[:space:]]*$' \ | psql -c " drop table if exists $table cascade; create table $table ( gene_symbol text , primary_fbgn text , secondary_fbgns text , annotation_id text , secondary_annotation_ids text ); copy $table from stdin csv delimiter E'\t'; "; # count on master: echo "select current_setting('port') port,count(*) from $table"|psql -qtXp 6564 # count on wal_receiver_01 (sync replica): echo "select current_setting('port') port,count(*) from $table"|psql -qtXp 6565 # count on wal_receiver_02 (async replica): echo "select current_setting('port') port,count(*) from $table"|psql -qtXp 6566 I expected the rowcounts from master and sync replica to always be the same. Initially this seemed to be the case, but when I run the above sequence in a while loop for a few minutes about 10% of rowcounts from the sync-replica are not equal to the master. Perhaps not a likely scenario, but surely such a deviating rowcount on a sync replica should not be possible? thank you, Erik Rijkers -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
