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Add 'logical_decoding_mode' GUC. 

This enables streaming or serializing changes immediately in logical
decoding. This parameter is intended to be used to test logical decoding
and replication of large transactions for which otherwise we need to
generate the changes till logical_decoding_work_mem is reached.

This helps in reducing the timing of existing tests related to logical
replication of in-progress transactions and will help in writing tests for
for the upcoming feature for parallelly applying large in-progress
transactions.

Author: Shi yu
Reviewed-by: Sawada Masahiko, Shveta Mallik, Amit Kapila, Dilip Kumar, Kuroda Hayato, Kyotaro Horiguchi
Discussion: https://postgr.es/m/OSZPR01MB63104E7449DBE41932DB19F1FD1B9@OSZPR01MB6310.jpnprd01.prod.outlook.com
This commit is contained in:
Amit Kapila 2022-12-26 08:58:16 +05:30
parent d3c0cc4447
commit 5de94a041e
9 changed files with 134 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
doc/src/sgml/config.sgml
View File

@ -11597,6 +11597,34 @@ LOG: CleanUpLock: deleting: lock(0xb7acd844) id(24688,24696,0,0,0,1)
</listitem>
</varlistentry>
<varlistentry id="guc-logical-decoding-mode" xreflabel="logical_decoding_mode">
<term><varname>logical_decoding_mode</varname> (<type>enum</type>)
<indexterm>
<primary><varname>logical_decoding_mode</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Allows streaming or serializing changes immediately in logical decoding.
The allowed values of <varname>logical_decoding_mode</varname> are
<literal>buffered</literal> and <literal>immediate</literal>. When set
to <literal>immediate</literal>, stream each change if
<literal>streaming</literal> option (see optional parameters set by
<link linkend="sql-createsubscription"><command>CREATE SUBSCRIPTION</command></link>)
is enabled, otherwise, serialize each change. When set to
<literal>buffered</literal>, which is the default, decoding will stream
or serialize changes when <varname>logical_decoding_work_mem</varname>
is reached.
</para>
<para>
This parameter is intended to be used to test logical decoding and
replication of large transactions for which otherwise we need to
generate the changes till <varname>logical_decoding_work_mem</varname>
is reached.
</para>
</listitem>
</varlistentry>
</variablelist>
</sect1>
<sect1 id="runtime-config-short">

33
src/backend/replication/logical/reorderbuffer.c
View File

@ -209,6 +209,9 @@ typedef struct ReorderBufferDiskChange
int logical_decoding_work_mem;
static const Size max_changes_in_memory = 4096; /* XXX for restore only */
/* GUC variable */
int logical_decoding_mode = LOGICAL_DECODING_MODE_BUFFERED;
/* ---------------------------------------
* primary reorderbuffer support routines
* ---------------------------------------
@ -3540,7 +3543,10 @@ ReorderBufferLargestStreamableTopTXN(ReorderBuffer *rb)
/*
* Check whether the logical_decoding_work_mem limit was reached, and if yes
* pick the largest (sub)transaction at-a-time to evict and spill its changes to
* disk until we reach under the memory limit.
* disk or send to the output plugin until we reach under the memory limit.
*
* If logical_decoding_mode is set to "immediate", stream or serialize the changes
* immediately.
*
* XXX At this point we select the transactions until we reach under the memory
* limit, but we might also adapt a more elaborate eviction strategy - for example
@ -3552,20 +3558,27 @@ ReorderBufferCheckMemoryLimit(ReorderBuffer *rb)
{
ReorderBufferTXN *txn;
/* bail out if we haven't exceeded the memory limit */
if (rb->size < logical_decoding_work_mem * 1024L)
/*
* Bail out if logical_decoding_mode is buffered and we haven't exceeded
* the memory limit.
*/
if (logical_decoding_mode == LOGICAL_DECODING_MODE_BUFFERED &&
rb->size < logical_decoding_work_mem * 1024L)
return;
/*
* Loop until we reach under the memory limit. One might think that just
* by evicting the largest (sub)transaction we will come under the memory
* limit based on assumption that the selected transaction is at least as
* large as the most recent change (which caused us to go over the memory
* limit). However, that is not true because a user can reduce the
* logical_decoding_work_mem to a smaller value before the most recent
* If logical_decoding_mode is immediate, loop until there's no change.
* Otherwise, loop until we reach under the memory limit. One might think
* that just by evicting the largest (sub)transaction we will come under
* the memory limit based on assumption that the selected transaction is
* at least as large as the most recent change (which caused us to go over
* the memory limit). However, that is not true because a user can reduce
* the logical_decoding_work_mem to a smaller value before the most recent
* change.
*/
while (rb->size >= logical_decoding_work_mem * 1024L)
while (rb->size >= logical_decoding_work_mem * 1024L ||
(logical_decoding_mode == LOGICAL_DECODING_MODE_IMMEDIATE &&
rb->size > 0))
{
/*
* Pick the largest transaction (or subtransaction) and evict it from

17
src/backend/utils/misc/guc_tables.c
View File

@ -395,6 +395,12 @@ static const struct config_enum_entry ssl_protocol_versions_info[] = {
{NULL, 0, false}
};
static const struct config_enum_entry logical_decoding_mode_options[] = {
{"buffered", LOGICAL_DECODING_MODE_BUFFERED, false},
{"immediate", LOGICAL_DECODING_MODE_IMMEDIATE, false},
{NULL, 0, false}
};
StaticAssertDecl(lengthof(ssl_protocol_versions_info) == (PG_TLS1_3_VERSION + 2),
"array length mismatch");
@ -4877,6 +4883,17 @@ struct config_enum ConfigureNamesEnum[] =
NULL, NULL, NULL
},
{
{"logical_decoding_mode", PGC_USERSET, DEVELOPER_OPTIONS,
gettext_noop("Allows streaming or serializing each change in logical decoding."),
NULL,
GUC_NOT_IN_SAMPLE
},
&logical_decoding_mode,
LOGICAL_DECODING_MODE_BUFFERED, logical_decoding_mode_options,
NULL, NULL, NULL
},
/* End-of-list marker */
{
{NULL, 0, 0, NULL, NULL}, NULL, 0, NULL, NULL, NULL, NULL

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

@ -18,6 +18,14 @@
#include "utils/timestamp.h"
extern PGDLLIMPORT int logical_decoding_work_mem;
extern PGDLLIMPORT int logical_decoding_mode;
/* possible values for logical_decoding_mode */
typedef enum
{
LOGICAL_DECODING_MODE_BUFFERED,
LOGICAL_DECODING_MODE_IMMEDIATE
} LogicalDecodingMode;
/* an individual tuple, stored in one chunk of memory */
typedef struct ReorderBufferTupleBuf

18
src/test/subscription/t/016_stream_subxact.pl
View File

@ -1,7 +1,7 @@
# Copyright (c) 2021-2022, PostgreSQL Global Development Group
# Test streaming of large transaction containing large subtransactions
# Test streaming of transaction containing subtransactions
use strict;
use warnings;
use PostgreSQL::Test::Cluster;
@ -12,7 +12,7 @@ use Test::More;
my $node_publisher = PostgreSQL::Test::Cluster->new('publisher');
$node_publisher->init(allows_streaming => 'logical');
$node_publisher->append_conf('postgresql.conf',
'logical_decoding_work_mem = 64kB');
'logical_decoding_mode = immediate');
$node_publisher->start;
# Create subscriber node
@ -49,27 +49,27 @@ my $result =
"SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(2|2|2), 'check initial data was copied to subscriber');
# Insert, update and delete enough rows to exceed 64kB limit.
# Insert, update and delete some rows.
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series( 3, 500) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
SAVEPOINT s1;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(501, 1000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(6, 8) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
SAVEPOINT s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(1001, 1500) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(9, 11) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
SAVEPOINT s3;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(1501, 2000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(12, 14) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
SAVEPOINT s4;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(2001, 2500) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(15, 17) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
COMMIT;
@ -80,7 +80,7 @@ $node_publisher->wait_for_catchup($appname);
$result =
$node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c), count(d = 999) FROM test_tab");
is($result, qq(1667|1667|1667),
is($result, qq(12|12|12),
'check data was copied to subscriber in streaming mode and extra columns contain local defaults'
);

50
src/test/subscription/t/018_stream_subxact_abort.pl
View File

@ -1,7 +1,7 @@
# Copyright (c) 2021-2022, PostgreSQL Global Development Group
# Test streaming of large transaction containing multiple subtransactions and rollbacks
# Test streaming of transaction containing multiple subtransactions and rollbacks
use strict;
use warnings;
use PostgreSQL::Test::Cluster;
@ -12,7 +12,7 @@ use Test::More;
my $node_publisher = PostgreSQL::Test::Cluster->new('publisher');
$node_publisher->init(allows_streaming => 'logical');
$node_publisher->append_conf('postgresql.conf',
'logical_decoding_work_mem = 64kB');
'logical_decoding_mode = immediate');
$node_publisher->start;
# Create subscriber node
@ -48,25 +48,25 @@ my $result =
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(2|0), 'check initial data was copied to subscriber');
# large (streamed) transaction with DDL, DML and ROLLBACKs
# streamed transaction with DDL, DML and ROLLBACKs
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3,500) s(i);
INSERT INTO test_tab VALUES (3, md5(3::text));
SAVEPOINT s1;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(501,1000) s(i);
INSERT INTO test_tab VALUES (4, md5(4::text));
SAVEPOINT s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(1001,1500) s(i);
INSERT INTO test_tab VALUES (5, md5(5::text));
SAVEPOINT s3;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(1501,2000) s(i);
INSERT INTO test_tab VALUES (6, md5(6::text));
ROLLBACK TO s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(2001,2500) s(i);
INSERT INTO test_tab VALUES (7, md5(7::text));
ROLLBACK TO s1;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(2501,3000) s(i);
INSERT INTO test_tab VALUES (8, md5(8::text));
SAVEPOINT s4;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3001,3500) s(i);
INSERT INTO test_tab VALUES (9, md5(9::text));
SAVEPOINT s5;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3501,4000) s(i);
INSERT INTO test_tab VALUES (10, md5(10::text));
COMMIT;
});
@ -75,24 +75,24 @@ $node_publisher->wait_for_catchup($appname);
$result =
$node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(2000|0),
is($result, qq(6|0),
'check rollback to savepoint was reflected on subscriber and extra columns contain local defaults'
);
# large (streamed) transaction with subscriber receiving out of order
# subtransaction ROLLBACKs
# streamed transaction with subscriber receiving out of order subtransaction
# ROLLBACKs
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(4001,4500) s(i);
INSERT INTO test_tab VALUES (11, md5(11::text));
SAVEPOINT s1;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(5001,5500) s(i);
INSERT INTO test_tab VALUES (12, md5(12::text));
SAVEPOINT s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(6001,6500) s(i);
INSERT INTO test_tab VALUES (13, md5(13::text));
SAVEPOINT s3;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(7001,7500) s(i);
INSERT INTO test_tab VALUES (14, md5(14::text));
RELEASE s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(8001,8500) s(i);
INSERT INTO test_tab VALUES (15, md5(15::text));
ROLLBACK TO s1;
COMMIT;
});
@ -102,18 +102,18 @@ $node_publisher->wait_for_catchup($appname);
$result =
$node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(2500|0),
is($result, qq(7|0),
'check rollback to savepoint was reflected on subscriber');
# large (streamed) transaction with subscriber receiving rollback
# streamed transaction with subscriber receiving rollback
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(8501,9000) s(i);
INSERT INTO test_tab VALUES (16, md5(16::text));
SAVEPOINT s1;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(9001,9500) s(i);
INSERT INTO test_tab VALUES (17, md5(17::text));
SAVEPOINT s2;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(9501,10000) s(i);
INSERT INTO test_tab VALUES (18, md5(18::text));
ROLLBACK;
});
@ -122,7 +122,7 @@ $node_publisher->wait_for_catchup($appname);
$result =
$node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(2500|0), 'check rollback was reflected on subscriber');
is($result, qq(7|0), 'check rollback was reflected on subscriber');
$node_subscriber->stop;
$node_publisher->stop;

18
src/test/subscription/t/019_stream_subxact_ddl_abort.pl
View File

@ -1,7 +1,7 @@
# Copyright (c) 2021-2022, PostgreSQL Global Development Group
# Test streaming of large transaction with subtransactions, DDLs, DMLs, and
# Test streaming of transaction with subtransactions, DDLs, DMLs, and
# rollbacks
use strict;
use warnings;
@ -13,7 +13,7 @@ use Test::More;
my $node_publisher = PostgreSQL::Test::Cluster->new('publisher');
$node_publisher->init(allows_streaming => 'logical');
$node_publisher->append_conf('postgresql.conf',
'logical_decoding_work_mem = 64kB');
'logical_decoding_mode = immediate');
$node_publisher->start;
# Create subscriber node
@ -49,23 +49,23 @@ my $result =
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(2|0), 'check initial data was copied to subscriber');
# large (streamed) transaction with DDL, DML and ROLLBACKs
# streamed transaction with DDL, DML and ROLLBACKs
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3,500) s(i);
INSERT INTO test_tab VALUES (3, md5(3::text));
ALTER TABLE test_tab ADD COLUMN c INT;
SAVEPOINT s1;
INSERT INTO test_tab SELECT i, md5(i::text), -i FROM generate_series(501,1000) s(i);
INSERT INTO test_tab VALUES (4, md5(4::text), -4);
ALTER TABLE test_tab ADD COLUMN d INT;
SAVEPOINT s2;
INSERT INTO test_tab SELECT i, md5(i::text), -i, 2*i FROM generate_series(1001,1500) s(i);
INSERT INTO test_tab VALUES (5, md5(5::text), -5, 5*2);
ALTER TABLE test_tab ADD COLUMN e INT;
SAVEPOINT s3;
INSERT INTO test_tab SELECT i, md5(i::text), -i, 2*i, -3*i FROM generate_series(1501,2000) s(i);
INSERT INTO test_tab VALUES (6, md5(6::text), -6, 6*2, -6*3);
ALTER TABLE test_tab DROP COLUMN c;
ROLLBACK TO s1;
INSERT INTO test_tab SELECT i, md5(i::text), i FROM generate_series(501,1000) s(i);
INSERT INTO test_tab VALUES (4, md5(4::text), 4);
COMMIT;
});
@ -74,7 +74,7 @@ $node_publisher->wait_for_catchup($appname);
$result =
$node_subscriber->safe_psql('postgres',
"SELECT count(*), count(c) FROM test_tab");
is($result, qq(1000|500),
is($result, qq(4|1),
'check rollback to savepoint was reflected on subscriber and extra columns contain local defaults'
);

28
src/test/subscription/t/023_twophase_stream.pl
View File

@ -18,7 +18,7 @@ $node_publisher->init(allows_streaming => 'logical');
$node_publisher->append_conf(
'postgresql.conf', qq(
max_prepared_transactions = 10
logical_decoding_work_mem = 64kB
logical_decoding_mode = immediate
));
$node_publisher->start;
@ -80,11 +80,11 @@ is($result, qq(2|2|2), 'check initial data was copied to subscriber');
###############################
# check that 2PC gets replicated to subscriber
# Insert, update and delete enough rows to exceed the 64kB limit.
# Insert, update and delete some rows.
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) 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';});
@ -105,7 +105,7 @@ $node_publisher->wait_for_catchup($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),
is($result, qq(4|4|4),
'Rows inserted by 2PC have committed on subscriber, and extra columns contain local defaults'
);
$result = $node_subscriber->safe_psql('postgres',
@ -124,11 +124,11 @@ is($result, qq(0), 'transaction is committed on subscriber');
# 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.
# Then insert, update and delete some rows.
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
@ -158,7 +158,7 @@ is($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.
# 1. insert, update and delete some rows.
# 2. Then server crashes before the 2PC transaction is committed.
# 3. After servers are restarted the pending transaction is committed.
#
@ -169,7 +169,7 @@ is($result, qq(0), 'transaction is aborted on subscriber');
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) 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';});
@ -188,7 +188,7 @@ $node_publisher->wait_for_catchup($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),
is($result, qq(4|4|4),
'Rows inserted by 2PC have committed on subscriber, and extra columns contain local defaults'
);
@ -206,11 +206,11 @@ is($result, qq(3334|3334|3334),
# 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.
# Then insert, update and delete some rows.
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) s(i);
UPDATE test_tab SET b = md5(b) WHERE mod(a,2) = 0;
DELETE FROM test_tab WHERE mod(a,3) = 0;
PREPARE TRANSACTION 'test_prepared_tab';});
@ -257,11 +257,11 @@ is($result, qq(0), 'transaction is aborted on subscriber');
# 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.
# Then insert, update and delete some rows.
$node_publisher->safe_psql(
'postgres', q{
BEGIN;
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5000) s(i);
INSERT INTO test_tab SELECT i, md5(i::text) FROM generate_series(3, 5) 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';});
@ -287,7 +287,7 @@ $node_publisher->wait_for_catchup($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),
is($result, qq(5|5|5),
'Rows inserted by 2PC (as well as outside insert) have committed on subscriber, and extra columns contain local defaults'
);

1
src/tools/pgindent/typedefs.list
View File

@ -1456,6 +1456,7 @@ LogicalDecodeStreamStopCB
LogicalDecodeStreamTruncateCB
LogicalDecodeTruncateCB
LogicalDecodingContext
LogicalDecodingMode
LogicalErrorCallbackState
LogicalOutputPluginInit
LogicalOutputPluginWriterPrepareWrite