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Add prepare API support for streaming transactions in logical replication. 

Commit a8fd13cab0 added support for prepared transactions to built-in
logical replication via a new option "two_phase" for a subscription. The
"two_phase" option was not allowed with the existing streaming option.

This commit permits the combination of "streaming" and "two_phase"
subscription options. It extends the pgoutput plugin and the subscriber
side code to add the prepare API for streaming transactions which will
apply the changes accumulated in the spool-file at prepare time.

Author: Peter Smith and Ajin Cherian
Reviewed-by: Vignesh C, Amit Kapila, Greg Nancarrow
Tested-By: Haiying Tang
Discussion: https://postgr.es/m/02DA5F5E-CECE-4D9C-8B4B-418077E2C010@postgrespro.ru
Discussion: https://postgr.es/m/CAMGcDxeqEpWj3fTXwqhSwBdXd2RS9jzwWscO-XbeCfso6ts3+Q@mail.gmail.com
This commit is contained in:
Amit Kapila 2021-08-04 07:47:06 +05:30
parent 6424337073
commit 63cf61cdeb
12 changed files with 667 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
doc/src/sgml/logicaldecoding.sgml
View File

@ -1199,6 +1199,9 @@ OutputPluginWrite(ctx, true);
<function>stream_abort_cb</function>, <function>stream_commit_cb</function>
and <function>stream_change_cb</function>) and two optional callbacks
(<function>stream_message_cb</function> and <function>stream_truncate_cb</function>).
Also, if streaming of two-phase commands is to be supported, then additional
callbacks must be provided. (See <xref linkend="logicaldecoding-two-phase-commits"/>
for details).
</para>
<para>
@ -1237,7 +1240,13 @@ stream_start_cb(...); &lt;-- start of second block of changes
stream_change_cb(...);
stream_stop_cb(...); &lt;-- end of second block of changes
stream_commit_cb(...); &lt;-- commit of the streamed transaction
[a. when using normal commit]
stream_commit_cb(...); &lt;-- commit of the streamed transaction
[b. when using two-phase commit]
stream_prepare_cb(...); &lt;-- prepare the streamed transaction
commit_prepared_cb(...); &lt;-- commit of the prepared transaction
</programlisting>
</para>

76
doc/src/sgml/protocol.sgml
View File

@ -7411,7 +7411,7 @@ Stream Abort
</variablelist>
<para>
The following messages (Begin Prepare, Prepare, Commit Prepared, Rollback Prepared)
The following messages (Begin Prepare, Prepare, Commit Prepared, Rollback Prepared, Stream Prepare)
are available since protocol version 3.
</para>
@ -7714,6 +7714,80 @@ are available since protocol version 3.
</listitem>
</varlistentry>
<varlistentry>
<term>Stream Prepare</term>
<listitem>
<para>
<variablelist>
<varlistentry>
<term>Byte1('p')</term>
<listitem><para>
Identifies the message as a two-phase stream prepare message.
</para></listitem>
</varlistentry>
<varlistentry>
<term>
Int8(0)
</term>
<listitem><para>
Flags; currently unused.
</para></listitem>
</varlistentry>
<varlistentry>
<term>
Int64 (XLogRecPtr)
</term>
<listitem><para>
The LSN of the prepare.
</para></listitem>
</varlistentry>
<varlistentry>
<term>
Int64 (XLogRecPtr)
</term>
<listitem><para>
The end LSN of the prepare transaction.
</para></listitem>
</varlistentry>
<varlistentry>
<term>
Int64 (TimestampTz)
</term>
<listitem><para>
Prepare timestamp of the transaction. The value is in number
of microseconds since PostgreSQL epoch (2000-01-01).
</para></listitem>
</varlistentry>
<varlistentry>
<term>
Int32 (TransactionId)
</term>
<listitem><para>
Xid of the transaction.
</para></listitem>
</varlistentry>
<varlistentry>
<term>String</term>
<listitem><para>
The user defined GID of the two-phase transaction.
</para></listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
</varlistentry>
</variablelist>
<para>

10
doc/src/sgml/ref/create_subscription.sgml
View File

@ -238,11 +238,6 @@ CREATE SUBSCRIPTION <replaceable class="parameter">subscription_name</replaceabl
subscriber as a whole.
</para>
<para>
The <literal>streaming</literal> option cannot be used with the
<literal>two_phase</literal> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
@ -269,11 +264,6 @@ CREATE SUBSCRIPTION <replaceable class="parameter">subscription_name</replaceabl
to know the actual two-phase state.
</para>
<para>
The <literal>two_phase</literal> option cannot be used with the
<literal>streaming</literal> option.
</para>
</listitem>
</varlistentry>
</variablelist></para>

25
src/backend/commands/subscriptioncmds.c
View File

@ -335,25 +335,6 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
errmsg("subscription with %s must also set %s",
"slot_name = NONE", "create_slot = false")));
}
/*
* Do additional checking for the disallowed combination of two_phase and
* streaming. While streaming and two_phase can theoretically be
* supported, it needs more analysis to allow them together.
*/
if (opts->twophase &&
IsSet(supported_opts, SUBOPT_TWOPHASE_COMMIT) &&
IsSet(opts->specified_opts, SUBOPT_TWOPHASE_COMMIT))
{
if (opts->streaming &&
IsSet(supported_opts, SUBOPT_STREAMING) &&
IsSet(opts->specified_opts, SUBOPT_STREAMING))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
/*- translator: both %s are strings of the form "option = value" */
errmsg("%s and %s are mutually exclusive options",
"two_phase = true", "streaming = true")));
}
}
/*
@ -933,12 +914,6 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
if (IsSet(opts.specified_opts, SUBOPT_STREAMING))
{
if ((sub->twophasestate != LOGICALREP_TWOPHASE_STATE_DISABLED) && opts.streaming)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot set %s for two-phase enabled subscription",
"streaming = true")));
values[Anum_pg_subscription_substream - 1] =
BoolGetDatum(opts.streaming);
replaces[Anum_pg_subscription_substream - 1] = true;

29
src/backend/replication/logical/proto.c
View File

@ -145,7 +145,8 @@ logicalrep_read_begin_prepare(StringInfo in, LogicalRepPreparedTxnData *begin_da
}
/*
* The core functionality for logicalrep_write_prepare.
* The core functionality for logicalrep_write_prepare and
* logicalrep_write_stream_prepare.
*/
static void
logicalrep_write_prepare_common(StringInfo out, LogicalRepMsgType type,
@ -188,7 +189,8 @@ logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,
}
/*
* The core functionality for logicalrep_read_prepare.
* The core functionality for logicalrep_read_prepare and
* logicalrep_read_stream_prepare.
*/
static void
logicalrep_read_prepare_common(StringInfo in, char *msgtype,
@ -209,6 +211,8 @@ logicalrep_read_prepare_common(StringInfo in, char *msgtype,
elog(ERROR, "end_lsn is not set in %s message", msgtype);
prepare_data->prepare_time = pq_getmsgint64(in);
prepare_data->xid = pq_getmsgint(in, 4);
if (prepare_data->xid == InvalidTransactionId)
elog(ERROR, "invalid two-phase transaction ID in %s message", msgtype);
/* read gid (copy it into a pre-allocated buffer) */
strlcpy(prepare_data->gid, pq_getmsgstring(in), sizeof(prepare_data->gid));
@ -339,6 +343,27 @@ logicalrep_read_rollback_prepared(StringInfo in,
strlcpy(rollback_data->gid, pq_getmsgstring(in), sizeof(rollback_data->gid));
}
/*
* Write STREAM PREPARE to the output stream.
*/
void
logicalrep_write_stream_prepare(StringInfo out,
ReorderBufferTXN *txn,
XLogRecPtr prepare_lsn)
{
logicalrep_write_prepare_common(out, LOGICAL_REP_MSG_STREAM_PREPARE,
txn, prepare_lsn);
}
/*
* Read STREAM PREPARE from the stream.
*/
void
logicalrep_read_stream_prepare(StringInfo in, LogicalRepPreparedTxnData *prepare_data)
{
logicalrep_read_prepare_common(in, "stream prepare", prepare_data);
}
/*
* Write ORIGIN to the output stream.
*/

56
src/backend/replication/logical/worker.c
View File

@ -1052,6 +1052,56 @@ apply_handle_rollback_prepared(StringInfo s)
pgstat_report_activity(STATE_IDLE, NULL);
}
/*
* Handle STREAM PREPARE.
*
* Logic is in two parts:
* 1. Replay all the spooled operations
* 2. Mark the transaction as prepared
*/
static void
apply_handle_stream_prepare(StringInfo s)
{
LogicalRepPreparedTxnData prepare_data;
if (in_streamed_transaction)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg_internal("STREAM PREPARE message without STREAM STOP")));
/* Tablesync should never receive prepare. */
if (am_tablesync_worker())
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg_internal("tablesync worker received a STREAM PREPARE message")));
logicalrep_read_stream_prepare(s, &prepare_data);
elog(DEBUG1, "received prepare for streamed transaction %u", prepare_data.xid);
/* Replay all the spooled operations. */
apply_spooled_messages(prepare_data.xid, prepare_data.prepare_lsn);
/* Mark the transaction as prepared. */
apply_handle_prepare_internal(&prepare_data);
CommitTransactionCommand();
pgstat_report_stat(false);
store_flush_position(prepare_data.end_lsn);
in_remote_transaction = false;
/* unlink the files with serialized changes and subxact info. */
stream_cleanup_files(MyLogicalRepWorker->subid, prepare_data.xid);
/* Process any tables that are being synchronized in parallel. */
process_syncing_tables(prepare_data.end_lsn);
pgstat_report_activity(STATE_IDLE, NULL);
}
/*
* Handle ORIGIN message.
*
@ -1291,7 +1341,7 @@ apply_spooled_messages(TransactionId xid, XLogRecPtr lsn)
*/
oldcxt = MemoryContextSwitchTo(TopTransactionContext);
/* open the spool file for the committed transaction */
/* Open the spool file for the committed/prepared transaction */
changes_filename(path, MyLogicalRepWorker->subid, xid);
elog(DEBUG1, "replaying changes from file \"%s\"", path);
@ -2357,6 +2407,10 @@ apply_dispatch(StringInfo s)
case LOGICAL_REP_MSG_ROLLBACK_PREPARED:
apply_handle_rollback_prepared(s);
return;
case LOGICAL_REP_MSG_STREAM_PREPARE:
apply_handle_stream_prepare(s);
return;
}
ereport(ERROR,

33
src/backend/replication/pgoutput/pgoutput.c
View File

@ -71,6 +71,8 @@ static void pgoutput_stream_abort(struct LogicalDecodingContext *ctx,
static void pgoutput_stream_commit(struct LogicalDecodingContext *ctx,
ReorderBufferTXN *txn,
XLogRecPtr commit_lsn);
static void pgoutput_stream_prepare_txn(LogicalDecodingContext *ctx,
ReorderBufferTXN *txn, XLogRecPtr prepare_lsn);
static bool publications_valid;
static bool in_streaming;
@ -175,7 +177,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
cb->stream_message_cb = pgoutput_message;
cb->stream_truncate_cb = pgoutput_truncate;
/* transaction streaming - two-phase commit */
cb->stream_prepare_cb = NULL;
cb->stream_prepare_cb = pgoutput_stream_prepare_txn;
}
static void
@ -280,17 +282,6 @@ parse_output_parameters(List *options, PGOutputData *data)
}
else
elog(ERROR, "unrecognized pgoutput option: %s", defel->defname);
/*
* Do additional checking for the disallowed combination of two_phase
* and streaming. While streaming and two_phase can theoretically be
* supported, it needs more analysis to allow them together.
*/
if (data->two_phase && data->streaming)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("%s and %s are mutually exclusive options",
"two_phase", "streaming")));
}
}
@ -1029,6 +1020,24 @@ pgoutput_stream_commit(struct LogicalDecodingContext *ctx,
cleanup_rel_sync_cache(txn->xid, true);
}
/*
* PREPARE callback (for streaming two-phase commit).
*
* Notify the downstream to prepare the transaction.
*/
static void
pgoutput_stream_prepare_txn(LogicalDecodingContext *ctx,
ReorderBufferTXN *txn,
XLogRecPtr prepare_lsn)
{
Assert(rbtxn_is_streamed(txn));
OutputPluginUpdateProgress(ctx);
OutputPluginPrepareWrite(ctx, true);
logicalrep_write_stream_prepare(ctx->out, txn, prepare_lsn);
OutputPluginWrite(ctx, true);
}
/*
* Initialize the relation schema sync cache for a decoding session.
*

8
src/include/replication/logicalproto.h
View File

@ -67,7 +67,8 @@ typedef enum LogicalRepMsgType
LOGICAL_REP_MSG_STREAM_START = 'S',
LOGICAL_REP_MSG_STREAM_END = 'E',
LOGICAL_REP_MSG_STREAM_COMMIT = 'c',
LOGICAL_REP_MSG_STREAM_ABORT = 'A'
LOGICAL_REP_MSG_STREAM_ABORT = 'A',
LOGICAL_REP_MSG_STREAM_PREPARE = 'p'
} LogicalRepMsgType;
/*
@ -196,7 +197,10 @@ extern void logicalrep_write_rollback_prepared(StringInfo out, ReorderBufferTXN
TimestampTz prepare_time);
extern void logicalrep_read_rollback_prepared(StringInfo in,
LogicalRepRollbackPreparedTxnData *rollback_data);
extern void logicalrep_write_stream_prepare(StringInfo out, ReorderBufferTXN *txn,
XLogRecPtr prepare_lsn);
extern void logicalrep_read_stream_prepare(StringInfo in,
LogicalRepPreparedTxnData *prepare_data);
extern void logicalrep_write_origin(StringInfo out, const char *origin,
XLogRecPtr origin_lsn);

24
src/test/regress/expected/subscription.out
View File

@ -282,27 +282,29 @@ WARNING: tables were not subscribed, you will have to run ALTER SUBSCRIPTION ..
--fail - alter of two_phase option not supported.
ALTER SUBSCRIPTION regress_testsub SET (two_phase = false);
ERROR: unrecognized subscription parameter: "two_phase"
--fail - cannot set streaming when two_phase enabled
-- but can alter streaming when two_phase enabled
ALTER SUBSCRIPTION regress_testsub SET (streaming = true);
ERROR: cannot set streaming = true for two-phase enabled subscription
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
\dRs+
List of subscriptions
Name | Owner | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit | Conninfo
-----------------+---------------------------+---------+-------------+--------+-----------+------------------+--------------------+-----------------------------
regress_testsub | regress_subscription_user | f | {testpub} | f | f | p | off | dbname=regress_doesnotexist
regress_testsub | regress_subscription_user | f | {testpub} | f | t | p | off | dbname=regress_doesnotexist
(1 row)
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
DROP SUBSCRIPTION regress_testsub;
-- fail - two_phase and streaming are mutually exclusive.
CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (streaming = true, two_phase = true);
ERROR: two_phase = true and streaming = true are mutually exclusive options
-- two_phase and streaming are compatible.
CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, streaming = true, two_phase = true);
WARNING: tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
\dRs+
List of subscriptions
Name | Owner | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit | Conninfo
------+-------+---------+-------------+--------+-----------+------------------+--------------------+----------
(0 rows)
List of subscriptions
Name | Owner | Enabled | Publication | Binary | Streaming | Two phase commit | Synchronous commit | Conninfo
-----------------+---------------------------+---------+-------------+--------+-----------+------------------+--------------------+-----------------------------
regress_testsub | regress_subscription_user | f | {testpub} | f | t | p | off | dbname=regress_doesnotexist
(1 row)
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
DROP SUBSCRIPTION regress_testsub;
RESET SESSION AUTHORIZATION;
DROP ROLE regress_subscription_user;
DROP ROLE regress_subscription_user2;

11
src/test/regress/sql/subscription.sql
View File

@ -215,20 +215,21 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
--fail - alter of two_phase option not supported.
ALTER SUBSCRIPTION regress_testsub SET (two_phase = false);
--fail - cannot set streaming when two_phase enabled
-- but can alter streaming when two_phase enabled
ALTER SUBSCRIPTION regress_testsub SET (streaming = true);
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
\dRs+
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
DROP SUBSCRIPTION regress_testsub;
-- fail - two_phase and streaming are mutually exclusive.
CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (streaming = true, two_phase = true);
-- two_phase and streaming are compatible.
CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, streaming = true, two_phase = true);
\dRs+
ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
DROP SUBSCRIPTION regress_testsub;
RESET SESSION AUTHORIZATION;
DROP ROLE regress_subscription_user;

179
src/test/subscription/t/022_twophase_cascade.pl
View File

@ -2,11 +2,14 @@
# Copyright (c) 2021, PostgreSQL Global Development Group
# Test cascading logical replication of 2PC.
#
# Includes tests for options 2PC (not-streaming) and also for 2PC (streaming).
#
use strict;
use warnings;
use PostgresNode;
use TestLib;
use Test::More tests => 27;
use Test::More tests => 41;
###############################
# Setup a cascade of pub/sub nodes.
@ -17,20 +20,26 @@ use Test::More tests => 27;
# node_A
my $node_A = PostgresNode->new('node_A');
$node_A->init(allows_streaming => 'logical');
$node_A->append_conf('postgresql.conf',
qq(max_prepared_transactions = 10));
$node_A->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
logical_decoding_work_mem = 64kB
));
$node_A->start;
# node_B
my $node_B = PostgresNode->new('node_B');
$node_B->init(allows_streaming => 'logical');
$node_B->append_conf('postgresql.conf',
qq(max_prepared_transactions = 10));
$node_B->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
logical_decoding_work_mem = 64kB
));
$node_B->start;
# node_C
my $node_C = PostgresNode->new('node_C');
$node_C->init(allows_streaming => 'logical');
$node_C->append_conf('postgresql.conf',
qq(max_prepared_transactions = 10));
$node_C->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
logical_decoding_work_mem = 64kB
));
$node_C->start;
# Create some pre-existing content on node_A
@ -45,12 +54,29 @@ $node_B->safe_psql('postgres',
$node_C->safe_psql('postgres',
"CREATE TABLE tab_full (a int PRIMARY KEY)");
# Create some pre-existing content on node_A (for streaming tests)
$node_A->safe_psql('postgres',
"CREATE TABLE test_tab (a int primary key, b varchar)");
$node_A->safe_psql('postgres',
"INSERT INTO test_tab VALUES (1, 'foo'), (2, 'bar')");
# Create the same tables on node_B and node_C
# columns a and b are compatible with same table name on node_A
$node_B->safe_psql('postgres',
"CREATE TABLE test_tab (a int primary key, b text, c timestamptz DEFAULT now(), d bigint DEFAULT 999)");
$node_C->safe_psql('postgres',
"CREATE TABLE test_tab (a int primary key, b text, c timestamptz DEFAULT now(), d bigint DEFAULT 999)");
# Setup logical replication
# -----------------------
# 2PC NON-STREAMING TESTS
# -----------------------
# node_A (pub) -> node_B (sub)
my $node_A_connstr = $node_A->connstr . ' dbname=postgres';
$node_A->safe_psql('postgres',
"CREATE PUBLICATION tap_pub_A FOR TABLE tab_full");
"CREATE PUBLICATION tap_pub_A FOR TABLE tab_full, test_tab");
my $appname_B = 'tap_sub_B';
$node_B->safe_psql('postgres', "
CREATE SUBSCRIPTION tap_sub_B
@ -61,7 +87,7 @@ $node_B->safe_psql('postgres', "
# node_B (pub) -> node_C (sub)
my $node_B_connstr = $node_B->connstr . ' dbname=postgres';
$node_B->safe_psql('postgres',
"CREATE PUBLICATION tap_pub_B FOR TABLE tab_full");
"CREATE PUBLICATION tap_pub_B FOR TABLE tab_full, test_tab");
my $appname_C = 'tap_sub_C';
$node_C->safe_psql('postgres', "
CREATE SUBSCRIPTION tap_sub_C
@ -203,6 +229,141 @@ is($result, qq(21), 'Rows committed are present on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT a FROM tab_full where a IN (21,22);");
is($result, qq(21), 'Rows committed are present on subscriber C');
# ---------------------
# 2PC + STREAMING TESTS
# ---------------------
my $oldpid_B = $node_A->safe_psql('postgres', "
SELECT pid FROM pg_stat_replication
WHERE application_name = '$appname_B';");
my $oldpid_C = $node_B->safe_psql('postgres', "
SELECT pid FROM pg_stat_replication
WHERE application_name = '$appname_C';");
# Setup logical replication (streaming = on)
$node_B->safe_psql('postgres', "
ALTER SUBSCRIPTION tap_sub_B
SET (streaming = on);");
$node_C->safe_psql('postgres', "
ALTER SUBSCRIPTION tap_sub_C
SET (streaming = on)");
# Wait for subscribers to finish initialization
$node_A->poll_query_until('postgres', "
SELECT pid != $oldpid_B FROM pg_stat_replication
WHERE application_name = '$appname_B';"
) or die "Timed out while waiting for apply to restart";
$node_B->poll_query_until('postgres', "
SELECT pid != $oldpid_C FROM pg_stat_replication
WHERE application_name = '$appname_C';"
) or die "Timed out while waiting for apply to restart";
###############################
# Test 2PC PREPARE / COMMIT PREPARED.
# 1. Data is streamed as a 2PC transaction.
# 2. Then do commit prepared.
#
# Expect all data is replicated on subscriber(s) after the commit.
###############################
# Insert, update and delete enough rows to exceed the 64kB limit.
# Then 2PC PREPARE
$node_A->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_A->wait_for_catchup($appname_B);
$node_B->wait_for_catchup($appname_C);
# check the transaction state is prepared on subscriber(s)
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber C');
# 2PC COMMIT
$node_A->safe_psql('postgres', "COMMIT PREPARED 'test_prepared_tab';");
$node_A->wait_for_catchup($appname_B);
$node_B->wait_for_catchup($appname_C);
# check that transaction was committed on subscriber(s)
$result = $node_B->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3334|3334|3334), 'Rows inserted by 2PC have committed on subscriber B, and extra columns have local defaults');
$result = $node_C->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3334|3334|3334), 'Rows inserted by 2PC have committed on subscriber C, and extra columns have local defaults');
# check the transaction state is ended on subscriber(s)
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is committed on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is committed on subscriber C');
###############################
# Test 2PC PREPARE with a nested ROLLBACK TO SAVEPOINT.
# 0. Cleanup from previous test leaving only 2 rows.
# 1. Insert one more row.
# 2. Record a SAVEPOINT.
# 3. Data is streamed using 2PC.
# 4. Do rollback to SAVEPOINT prior to the streamed inserts.
# 5. Then COMMIT PREPARED.
#
# Expect data after the SAVEPOINT is aborted leaving only 3 rows (= 2 original + 1 from step 1).
###############################
# First, delete the data except for 2 rows (delete will be replicated)
$node_A->safe_psql('postgres', "DELETE FROM test_tab WHERE a > 2;");
# 2PC PREPARE with a nested ROLLBACK TO SAVEPOINT
$node_A->safe_psql('postgres', "
BEGIN;
INSERT INTO test_tab VALUES (9999, 'foobar');
SAVEPOINT sp_inner;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
ROLLBACK TO SAVEPOINT sp_inner;
PREPARE TRANSACTION 'outer';
");
$node_A->wait_for_catchup($appname_B);
$node_B->wait_for_catchup($appname_C);
# check the transaction state prepared on subscriber(s)
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber C');
# 2PC COMMIT
$node_A->safe_psql('postgres', "COMMIT PREPARED 'outer';");
$node_A->wait_for_catchup($appname_B);
$node_B->wait_for_catchup($appname_C);
# check the transaction state is ended on subscriber
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is ended on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is ended on subscriber C');
# check inserts are visible at subscriber(s).
# All the streamed data (prior to the SAVEPOINT) should be rolled back.
# (9999, 'foobar') should be committed.
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM test_tab where b = 'foobar';");
is($result, qq(1), 'Rows committed are present on subscriber B');
$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM test_tab;");
is($result, qq(3), 'Rows committed are present on subscriber B');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM test_tab where b = 'foobar';");
is($result, qq(1), 'Rows committed are present on subscriber C');
$result = $node_C->safe_psql('postgres', "SELECT count(*) FROM test_tab;");
is($result, qq(3), 'Rows committed are present on subscriber C');
###############################
# check all the cleanup
###############################

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# Copyright (c) 2021, PostgreSQL Global Development Group
# Test logical replication of 2PC with streaming.
use strict;
use warnings;
use PostgresNode;
use TestLib;
use Test::More tests => 18;
###############################
# Setup
###############################
# Initialize publisher node
my $node_publisher = PostgresNode->new('publisher');
$node_publisher->init(allows_streaming => 'logical');
$node_publisher->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
logical_decoding_work_mem = 64kB
));
$node_publisher->start;
# Create subscriber node
my $node_subscriber = PostgresNode->new('subscriber');
$node_subscriber->init(allows_streaming => 'logical');
$node_subscriber->append_conf('postgresql.conf', qq(
max_prepared_transactions = 10
));
$node_subscriber->start;
# Create some pre-existing content on publisher
$node_publisher->safe_psql('postgres', "CREATE TABLE test_tab (a int primary key, b varchar)");
$node_publisher->safe_psql('postgres', "INSERT INTO test_tab VALUES (1, 'foo'), (2, 'bar')");
# Setup structure on subscriber (columns a and b are compatible with same table name on publisher)
$node_subscriber->safe_psql('postgres',
"CREATE TABLE test_tab (a int primary key, b text, c timestamptz DEFAULT now(), d bigint DEFAULT 999)");
# Setup logical replication (streaming = on)
my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
$node_publisher->safe_psql('postgres', "CREATE PUBLICATION tap_pub FOR TABLE test_tab");
my $appname = 'tap_sub';
$node_subscriber->safe_psql('postgres', "
CREATE SUBSCRIPTION tap_sub
CONNECTION '$publisher_connstr application_name=$appname'
PUBLICATION tap_pub
WITH (streaming = on, two_phase = on)");
# Wait for subscriber to finish initialization
$node_publisher->wait_for_catchup($appname);
# Also wait for initial table sync to finish
my $synced_query =
"SELECT count(1) = 0 FROM pg_subscription_rel WHERE srsubstate NOT IN ('r', 's');";
$node_subscriber->poll_query_until('postgres', $synced_query)
or die "Timed out while waiting for subscriber to synchronize data";
# Also wait for two-phase to be enabled
my $twophase_query =
"SELECT count(1) = 0 FROM pg_subscription WHERE subtwophasestate NOT IN ('e');";
$node_subscriber->poll_query_until('postgres', $twophase_query)
or die "Timed out while waiting for subscriber to enable twophase";
###############################
# Check initial data was copied to subscriber
###############################
my $result = $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(2|2|2), 'check initial data was copied to subscriber');
###############################
# Test 2PC PREPARE / COMMIT PREPARED.
# 1. Data is streamed as a 2PC transaction.
# 2. Then do commit prepared.
#
# Expect all data is replicated on subscriber side after the commit.
###############################
# check that 2PC gets replicated to subscriber
# Insert, update and delete enough rows to exceed the 64kB limit.
$node_publisher->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_publisher->wait_for_catchup($appname);
# check that transaction is in prepared state on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber');
# 2PC transaction gets committed
$node_publisher->safe_psql('postgres', "COMMIT PREPARED 'test_prepared_tab';");
$node_publisher->wait_for_catchup($appname);
# check that transaction is committed on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3334|3334|3334), 'Rows inserted by 2PC have committed on subscriber, and extra columns contain local defaults');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is committed on subscriber');
###############################
# Test 2PC PREPARE / ROLLBACK PREPARED.
# 1. Table is deleted back to 2 rows which are replicated on subscriber.
# 2. Data is streamed using 2PC.
# 3. Do rollback prepared.
#
# Expect data rolls back leaving only the original 2 rows.
###############################
# First, delete the data except for 2 rows (will be replicated)
$node_publisher->safe_psql('postgres', "DELETE FROM test_tab WHERE a > 2;");
# Then insert, update and delete enough rows to exceed the 64kB limit.
$node_publisher->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_publisher->wait_for_catchup($appname);
# check that transaction is in prepared state on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber');
# 2PC transaction gets aborted
$node_publisher->safe_psql('postgres', "ROLLBACK PREPARED 'test_prepared_tab';");
$node_publisher->wait_for_catchup($appname);
# check that transaction is aborted on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(2|2|2), 'Rows inserted by 2PC are rolled back, leaving only the original 2 rows');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is aborted on subscriber');
###############################
# Check that 2PC COMMIT PREPARED is decoded properly on crash restart.
# 1. insert, update and delete enough rows to exceed the 64kB limit.
# 2. Then server crashes before the 2PC transaction is committed.
# 3. After servers are restarted the pending transaction is committed.
#
# Expect all data is replicated on subscriber side after the commit.
# Note: both publisher and subscriber do crash/restart.
###############################
$node_publisher->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_subscriber->stop('immediate');
$node_publisher->stop('immediate');
$node_publisher->start;
$node_subscriber->start;
# commit post the restart
$node_publisher->safe_psql('postgres', "COMMIT PREPARED 'test_prepared_tab';");
$node_publisher->wait_for_catchup($appname);
# check inserts are visible
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3334|3334|3334), 'Rows inserted by 2PC have committed on subscriber, and extra columns contain local defaults');
###############################
# Do INSERT after the PREPARE but before ROLLBACK PREPARED.
# 1. Table is deleted back to 2 rows which are replicated on subscriber.
# 2. Data is streamed using 2PC.
# 3. A single row INSERT is done which is after the PREPARE.
# 4. Then do a ROLLBACK PREPARED.
#
# Expect the 2PC data rolls back leaving only 3 rows on the subscriber
# (the original 2 + inserted 1).
###############################
# First, delete the data except for 2 rows (will be replicated)
$node_publisher->safe_psql('postgres', "DELETE FROM test_tab WHERE a > 2;");
# Then insert, update and delete enough rows to exceed the 64kB limit.
$node_publisher->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_publisher->wait_for_catchup($appname);
# check that transaction is in prepared state on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber');
# Insert a different record (now we are outside of the 2PC transaction)
# Note: the 2PC transaction still holds row locks so make sure this insert is for a separate primary key
$node_publisher->safe_psql('postgres', "INSERT INTO test_tab VALUES (99999, 'foobar')");
# 2PC transaction gets aborted
$node_publisher->safe_psql('postgres', "ROLLBACK PREPARED 'test_prepared_tab';");
$node_publisher->wait_for_catchup($appname);
# check that transaction is aborted on subscriber,
# but the extra INSERT outside of the 2PC still was replicated
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3|3|3), 'check the outside insert was copied to subscriber');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is aborted on subscriber');
###############################
# Do INSERT after the PREPARE but before COMMIT PREPARED.
# 1. Table is deleted back to 2 rows which are replicated on subscriber.
# 2. Data is streamed using 2PC.
# 3. A single row INSERT is done which is after the PREPARE.
# 4. Then do a COMMIT PREPARED.
#
# Expect 2PC data + the extra row are on the subscriber
# (the 3334 + inserted 1 = 3335).
###############################
# First, delete the data except for 2 rows (will be replicated)
$node_publisher->safe_psql('postgres', "DELETE FROM test_tab WHERE a > 2;");
# Then insert, update and delete enough rows to exceed the 64kB limit.
$node_publisher->safe_psql('postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
$node_publisher->wait_for_catchup($appname);
# check that transaction is in prepared state on subscriber
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(1), 'transaction is prepared on subscriber');
# Insert a different record (now we are outside of the 2PC transaction)
# Note: the 2PC transaction still holds row locks so make sure this insert is for a separare primary key
$node_publisher->safe_psql('postgres', "INSERT INTO test_tab VALUES (99999, 'foobar')");
# 2PC transaction gets committed
$node_publisher->safe_psql('postgres', "COMMIT PREPARED 'test_prepared_tab';");
$node_publisher->wait_for_catchup($appname);
# check that transaction is committed on subscriber
$result = $node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(3335|3335|3335), 'Rows inserted by 2PC (as well as outside insert) have committed on subscriber, and extra columns contain local defaults');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_prepared_xacts;");
is($result, qq(0), 'transaction is committed on subscriber');
###############################
# check all the cleanup
###############################
$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_subscription");
is($result, qq(0), 'check subscription was dropped on subscriber');
$result = $node_publisher->safe_psql('postgres', "SELECT count(*) FROM pg_replication_slots");
is($result, qq(0), 'check replication slot was dropped on publisher');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_subscription_rel");
is($result, qq(0), 'check subscription relation status was dropped on subscriber');
$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM pg_replication_origin");
is($result, qq(0), 'check replication origin was dropped on subscriber');
$node_subscriber->stop('fast');
$node_publisher->stop('fast');