mirror of https://github.com/postgres/postgres
The output plugin accepts a new parameter (messages) that controls if logical decoding messages are written into the replication stream. It is useful for those clients that use pgoutput as an output plugin and needs to process messages that were written by pg_logical_emit_message(). Although logical streaming replication protocol supports logical decoding messages now, logical replication does not use this feature yet. Author: David Pirotte, Euler Taveira Reviewed-by: Euler Taveira, Andres Freund, Ashutosh Bapat, Amit Kapila Discussion: https://postgr.es/m/CADK3HHJ-+9SO7KuRLH=9Wa1rAo60Yreq1GFNkH_kd0=CdaWM+A@mail.gmail.compull/64/head
Amit Kapila
5 years ago
parent
531737ddad
commit
ac4645c015
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# Tests that logical decoding messages |
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use strict; |
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use warnings; |
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use PostgresNode; |
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use TestLib; |
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use Test::More tests => 5; |
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|
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# Create publisher node |
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my $node_publisher = get_new_node('publisher'); |
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$node_publisher->init(allows_streaming => 'logical'); |
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$node_publisher->start; |
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|
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# Create subscriber node |
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my $node_subscriber = get_new_node('subscriber'); |
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$node_subscriber->init(allows_streaming => 'logical'); |
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$node_subscriber->start; |
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|
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# Create some preexisting content on publisher |
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$node_publisher->safe_psql('postgres', |
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"CREATE TABLE tab_test (a int primary key)"); |
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|
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# Setup structure on subscriber |
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$node_subscriber->safe_psql('postgres', |
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"CREATE TABLE tab_test (a int primary key)"); |
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|
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# Setup logical replication |
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my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres'; |
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$node_publisher->safe_psql('postgres', "CREATE PUBLICATION tap_pub FOR TABLE tab_test"); |
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$node_subscriber->safe_psql('postgres', |
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"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub" |
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); |
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# Ensure a transactional logical decoding message shows up on the slot |
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$node_subscriber->safe_psql('postgres', "ALTER SUBSCRIPTION tap_sub DISABLE"); |
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$node_publisher->safe_psql('postgres', |
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"SELECT pg_logical_emit_message(true, 'pgoutput', 'a transactional message')" |
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); |
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my $result = $node_publisher->safe_psql( |
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'postgres', qq( |
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SELECT get_byte(data, 0) |
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FROM pg_logical_slot_peek_binary_changes('tap_sub', NULL, NULL, |
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'proto_version', '1', |
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'publication_names', 'tap_pub', |
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'messages', 'true') |
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)); |
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# 66 77 67 == B M C == BEGIN MESSAGE COMMIT |
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is($result, qq(66 |
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77 |
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67), |
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'messages on slot are B M C with message option'); |
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|
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$result = $node_publisher->safe_psql( |
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'postgres', qq( |
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SELECT get_byte(data, 1), encode(substr(data, 11, 8), 'escape') |
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FROM pg_logical_slot_peek_binary_changes('tap_sub', NULL, NULL, |
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'proto_version', '1', |
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'publication_names', 'tap_pub', |
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'messages', 'true') |
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OFFSET 1 LIMIT 1 |
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)); |
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is($result, qq(1|pgoutput), |
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"flag transactional is set to 1 and prefix is pgoutput"); |
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|
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$result = $node_publisher->safe_psql( |
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'postgres', qq( |
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SELECT get_byte(data, 0) |
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FROM pg_logical_slot_peek_binary_changes('tap_sub', NULL, NULL, |
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'proto_version', '1', |
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'publication_names', 'tap_pub') |
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)); |
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# 66 67 == B C == BEGIN COMMIT |
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is($result, qq(66 |
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67), |
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'option messages defaults to false so message (M) is not available on slot'); |
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$node_subscriber->safe_psql('postgres', "ALTER SUBSCRIPTION tap_sub ENABLE"); |
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$node_publisher->wait_for_catchup('tap_sub'); |
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# ensure a non-transactional logical decoding message shows up on the slot |
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$node_subscriber->safe_psql('postgres', "ALTER SUBSCRIPTION tap_sub DISABLE"); |
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$node_publisher->safe_psql('postgres', "INSERT INTO tab_test VALUES (1)"); |
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my $message_lsn = $node_publisher->safe_psql('postgres', |
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"SELECT pg_logical_emit_message(false, 'pgoutput', 'a non-transactional message')"); |
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$node_publisher->safe_psql('postgres', "INSERT INTO tab_test VALUES (2)"); |
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$result = $node_publisher->safe_psql( |
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'postgres', qq( |
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SELECT get_byte(data, 0), get_byte(data, 1) |
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FROM pg_logical_slot_peek_binary_changes('tap_sub', NULL, NULL, |
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'proto_version', '1', |
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'publication_names', 'tap_pub', |
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'messages', 'true') |
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WHERE lsn = '$message_lsn' AND xid = 0 |
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)); |
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is($result, qq(77|0), 'non-transactional message on slot is M'); |
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$node_subscriber->safe_psql('postgres', "ALTER SUBSCRIPTION tap_sub ENABLE"); |
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$node_publisher->wait_for_catchup('tap_sub'); |
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$node_subscriber->safe_psql('postgres', "ALTER SUBSCRIPTION tap_sub DISABLE"); |
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# wait for the replication connection to drop from the publisher |
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$node_publisher->poll_query_until('postgres', |
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'SELECT COUNT(*) FROM pg_catalog.pg_stat_replication', 0); |
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# Ensure a non-transactional logical decoding message shows up on the slot when |
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# it is emitted within an aborted transaction. The message won't emit until |
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# something advances the LSN, hence, we intentionally forces the server to |
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# switch to a new WAL file. |
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$node_publisher->safe_psql( |
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'postgres', qq( |
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BEGIN; |
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SELECT pg_logical_emit_message(false, 'pgoutput', |
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'a non-transactional message is available even if the transaction is aborted 1'); |
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INSERT INTO tab_test VALUES (3); |
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SELECT pg_logical_emit_message(true, 'pgoutput', |
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'a transactional message is not available if the transaction is aborted'); |
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SELECT pg_logical_emit_message(false, 'pgoutput', |
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'a non-transactional message is available even if the transaction is aborted 2'); |
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ROLLBACK; |
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SELECT pg_switch_wal(); |
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)); |
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$result = $node_publisher->safe_psql( |
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'postgres', qq( |
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SELECT get_byte(data, 0), get_byte(data, 1) |
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FROM pg_logical_slot_peek_binary_changes('tap_sub', NULL, NULL, |
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'proto_version', '1', |
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'publication_names', 'tap_pub', |
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'messages', 'true') |
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)); |
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is($result, qq(77|0 |
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77|0), |
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'non-transactional message on slot from aborted transaction is M'); |
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$node_subscriber->stop('fast'); |
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$node_publisher->stop('fast'); |
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