On Tue, Sep 30, 2025 at 12:22 PM Bertrand Drouvot <[email protected]> wrote: > > Hi, > > On Mon, Sep 29, 2025 at 12:54:24PM +0530, Ashutosh Bapat wrote: > > On Fri, Sep 26, 2025 at 10:28 PM Bertrand Drouvot > > <[email protected]> wrote: > > > > > > > > > > > > > > > > I don't think this is an issue. There is no way for the core to tell > > > > whether the plugin will provide stats or not, unless it sets that > > > > ctx->stats which happens in the startup callback. Till then it is > > > > rightly providing the values accumulated so far. Once the decoding > > > > starts, we know that the plugin is not providing any stats and we > > > > don't display anything. > > > > > > Yeah, I got the technical reasons, but I think there's a valid user > > > experience > > > concern here: seeing statistics for a plugin that doesn't actually support > > > statistics is misleading. > > > > > > > 3. If the plugin starts supporting statistics and midway discontinues > > its support, it already has a problem with backward compatibility. > > > > Practically it would 1 or 2, which are working fine. > > > > I don't think we will encounter case 3 practically. Do you have a > > practical use case where a plugin would discontinue supporting stats? > > Not that I can think of currently. That looks unlikely but wanted to raise > the point though. Maybe others see a use case and/or have a different point > of view. > > > > What we need is a call to pgstat_report_replslot() to display stats that > > > reflect > > > the current plugin behavior. We can't just call pgstat_report_replslot() > > > in say RestoreSlotFromDisk() because we really need the decoding to start. > > > > > > So one idea could be to set a flag (per slot) when > > > pgstat_report_replslot() > > > has been called (for good reasons) and check for this flag in > > > pg_stat_get_replication_slot(). > > > > > > If the flag is not set, then set the plugin fields to NULL. > > > If the flag is set, then display their values (like now). > > > > This approach will have the same problem. Till > > pgstat_report_replslot() is called, the old statistics will continue > > to be shown. > > I don't think so because the flag would not be set. > > > > And we should document that the plugin stats are not available (i.e are > > > NULL) > > > until the decoding has valid stats to report after startup. > > > > The current documentation is " It is NULL when statistics is not > > initialized or immediately after a reset or when not maintained by the > > output plugin.". I think that covers all the cases. > > Do you think the doc covers the case we discussed above? i.e when a plugin > discontinue supporting stats, it would display stats until the decoding > actually > starts.
Here's patchset addressing two issues: Issue 1: A plugin supports stats in version X. It stopped supporting the stats in version X + 1. It again started supporting stats in version X + 2. Plugin stats will be accumulated when it was at version X. When X + 1 is loaded, the stats will continue to report the stats accumulated (by version X) till the first startup_call for that replication slot happens. If the user knows (from documentation say) that X + 1 does not support stats, seeing statistics will mislead them. We don't know whether there's a practical need to do so. A plugin which flip-flops on stats is breaking backward compatibility. I have added a note in documentation for plugin authors, warning them that this isn't expected. I don't think it's worth adding complexity in code to support such a case unless we see a practical need for the same. Issue 2: Once X + 2 is loaded, further statistics are accumulated on the top of statistics accumulated by version X. Attached patch fixes issue 2 by zero'ing out the stats when the plugin does not report the statistics. The patchset also addresses your earlier review comments. -- Best Wishes, Ashutosh Bapat
From da8c610c0d2977f513fef25adb487ffd0199518d Mon Sep 17 00:00:00 2001 From: Ashutosh Bapat <[email protected]> Date: Fri, 27 Jun 2025 09:16:23 +0530 Subject: [PATCH 1/2] Report output plugin statistics in pg_stat_replication_slots As of now pg_stat_replication_slots reports statistics about the reorder buffer, but it does not report output plugin statistics like the amount of data filtered by the output plugin, amount of data sent downstream or the number of transactions sent downstream. This statistics is useful when investigating issues related to a slow downstream. This commit adds following fields to pg_stat_replication_slots - plugin_filtered_bytes is the amount of changes filtered out by the output plugin - plugin_sent_txns is the amount of transactions sent downstream by the output plugin - plugin_sent_bytes is the amount of data sent downstream by the output plugin. The prefix "plugin_" indicates that these counters are related to and maintained by the output plugin. An output plugin may choose not to initialize LogicalDecodingContext::stats, which holds these counters, in which case the above columns will be reported as NULL. Filtered bytes are reported next to total_bytes to keep these two closely related fields together. Additionally report name of the output plugin in the view for an easy reference. total_bytes and total_txns are the only fields remaining unqualified - they do not convey what those bytes and txns are. Hence rename them total_wal_bytes and total_wal_txns respectively to indicate that those counts come from WAL stream. Author: Ashutosh Bapat <[email protected]> Reviewed-by: Shveta Malik <[email protected]> Reviewed-by: Bertrand Drouvot <[email protected]> Reviewed-by: Ashutosh Sharma <[email protected]> Reviewed-by: Amit Kapila <[email protected]> Discussion: https://www.postgresql.org/message-id/CAExHW5s6KntzUyUoMbKR5dgwRmdV2Ay_2+AnTgYGAzo=qv6...@mail.gmail.com --- contrib/test_decoding/expected/stats.out | 77 ++++++++++--------- contrib/test_decoding/sql/stats.sql | 16 ++-- contrib/test_decoding/t/001_repl_stats.pl | 22 ++++-- contrib/test_decoding/test_decoding.c | 2 + doc/src/sgml/logicaldecoding.sgml | 28 +++++++ doc/src/sgml/monitoring.sgml | 70 +++++++++++++++-- src/backend/catalog/system_views.sql | 8 +- src/backend/replication/logical/logical.c | 28 ++++++- .../replication/logical/logicalfuncs.c | 8 ++ .../replication/logical/reorderbuffer.c | 3 +- src/backend/replication/pgoutput/pgoutput.c | 21 +++++ src/backend/replication/walsender.c | 7 ++ src/backend/utils/activity/pgstat_replslot.c | 11 ++- src/backend/utils/adt/pgstatfuncs.c | 34 ++++++-- src/include/catalog/pg_proc.dat | 6 +- src/include/pgstat.h | 8 +- src/include/replication/logical.h | 1 + src/include/replication/output_plugin.h | 13 ++++ src/include/replication/reorderbuffer.h | 1 + src/test/recovery/t/006_logical_decoding.pl | 12 +-- .../t/035_standby_logical_decoding.pl | 4 +- src/test/regress/expected/rules.out | 10 ++- src/test/subscription/t/001_rep_changes.pl | 11 +++ src/test/subscription/t/010_truncate.pl | 20 +++++ src/test/subscription/t/028_row_filter.pl | 11 +++ src/tools/pgindent/typedefs.list | 1 + 26 files changed, 344 insertions(+), 89 deletions(-) diff --git a/contrib/test_decoding/expected/stats.out b/contrib/test_decoding/expected/stats.out index de6dc416130..4834b3460a6 100644 --- a/contrib/test_decoding/expected/stats.out +++ b/contrib/test_decoding/expected/stats.out @@ -37,12 +37,17 @@ SELECT pg_stat_force_next_flush(); (1 row) -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; - slot_name | spill_txns | spill_count | total_txns | total_bytes -------------------------+------------+-------------+------------+------------- - regression_slot_stats1 | t | t | t | t - regression_slot_stats2 | t | t | t | t - regression_slot_stats3 | t | t | t | t +-- total_wal_txns may vary based on the background activity but plugin_sent_txns +-- should always be 1 since the background transactions are always skipped. +-- Filtered bytes would be set only when there's a change that was passed to the +-- plugin but was filtered out. Depending upon the background transactions, +-- filtered bytes may or may not be zero. +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes > 0 AS sent_bytes, plugin_filtered_bytes >= 0 AS filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; + slot_name | spill_txns | spill_count | total_wal_txns | total_wal_bytes | plugin_sent_txns | sent_bytes | filtered_bytes +------------------------+------------+-------------+----------------+-----------------+------------------+------------+---------------- + regression_slot_stats1 | t | t | t | t | 1 | t | t + regression_slot_stats2 | t | t | t | t | 1 | t | t + regression_slot_stats3 | t | t | t | t | 1 | t | t (3 rows) RESET logical_decoding_work_mem; @@ -53,12 +58,12 @@ SELECT pg_stat_reset_replication_slot('regression_slot_stats1'); (1 row) -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; - slot_name | spill_txns | spill_count | total_txns | total_bytes -------------------------+------------+-------------+------------+------------- - regression_slot_stats1 | t | t | f | f - regression_slot_stats2 | t | t | t | t - regression_slot_stats3 | t | t | t | t +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes > 0 AS sent_bytes, plugin_filtered_bytes >= 0 AS filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; + slot_name | spill_txns | spill_count | total_wal_txns | total_wal_bytes | plugin_sent_txns | sent_bytes | filtered_bytes +------------------------+------------+-------------+----------------+-----------------+------------------+------------+---------------- + regression_slot_stats1 | t | t | f | f | | | + regression_slot_stats2 | t | t | t | t | 1 | t | t + regression_slot_stats3 | t | t | t | t | 1 | t | t (3 rows) -- reset stats for all slots @@ -68,27 +73,27 @@ SELECT pg_stat_reset_replication_slot(NULL); (1 row) -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; - slot_name | spill_txns | spill_count | total_txns | total_bytes -------------------------+------------+-------------+------------+------------- - regression_slot_stats1 | t | t | f | f - regression_slot_stats2 | t | t | f | f - regression_slot_stats3 | t | t | f | f +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes, plugin_filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; + slot_name | spill_txns | spill_count | total_wal_txns | total_wal_bytes | plugin_sent_txns | plugin_sent_bytes | plugin_filtered_bytes +------------------------+------------+-------------+----------------+-----------------+------------------+-------------------+----------------------- + regression_slot_stats1 | t | t | f | f | | | + regression_slot_stats2 | t | t | f | f | | | + regression_slot_stats3 | t | t | f | f | | | (3 rows) -- verify accessing/resetting stats for non-existent slot does something reasonable SELECT * FROM pg_stat_get_replication_slot('do-not-exist'); - slot_name | spill_txns | spill_count | spill_bytes | stream_txns | stream_count | stream_bytes | total_txns | total_bytes | stats_reset ---------------+------------+-------------+-------------+-------------+--------------+--------------+------------+-------------+------------- - do-not-exist | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | + slot_name | spill_txns | spill_count | spill_bytes | stream_txns | stream_count | stream_bytes | total_wal_txns | total_wal_bytes | plugin_filtered_bytes | plugin_sent_txns | plugin_sent_bytes | stats_reset +--------------+------------+-------------+-------------+-------------+--------------+--------------+----------------+-----------------+-----------------------+------------------+-------------------+------------- + do-not-exist | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | | | (1 row) SELECT pg_stat_reset_replication_slot('do-not-exist'); ERROR: replication slot "do-not-exist" does not exist SELECT * FROM pg_stat_get_replication_slot('do-not-exist'); - slot_name | spill_txns | spill_count | spill_bytes | stream_txns | stream_count | stream_bytes | total_txns | total_bytes | stats_reset ---------------+------------+-------------+-------------+-------------+--------------+--------------+------------+-------------+------------- - do-not-exist | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | + slot_name | spill_txns | spill_count | spill_bytes | stream_txns | stream_count | stream_bytes | total_wal_txns | total_wal_bytes | plugin_filtered_bytes | plugin_sent_txns | plugin_sent_bytes | stats_reset +--------------+------------+-------------+-------------+-------------+--------------+--------------+----------------+-----------------+-----------------------+------------------+-------------------+------------- + do-not-exist | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | | | (1 row) -- spilling the xact @@ -121,20 +126,20 @@ SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count F -- Ensure stats can be repeatedly accessed using the same stats snapshot. See -- https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i%40alap3.anarazel.de BEGIN; -SELECT slot_name FROM pg_stat_replication_slots; - slot_name ------------------------- - regression_slot_stats1 - regression_slot_stats2 - regression_slot_stats3 +SELECT slot_name, plugin FROM pg_stat_replication_slots; + slot_name | plugin +------------------------+--------------- + regression_slot_stats1 | test_decoding + regression_slot_stats2 | test_decoding + regression_slot_stats3 | test_decoding (3 rows) -SELECT slot_name FROM pg_stat_replication_slots; - slot_name ------------------------- - regression_slot_stats1 - regression_slot_stats2 - regression_slot_stats3 +SELECT slot_name, plugin FROM pg_stat_replication_slots; + slot_name | plugin +------------------------+--------------- + regression_slot_stats1 | test_decoding + regression_slot_stats2 | test_decoding + regression_slot_stats3 | test_decoding (3 rows) COMMIT; diff --git a/contrib/test_decoding/sql/stats.sql b/contrib/test_decoding/sql/stats.sql index a022fe1bf07..99f513902d3 100644 --- a/contrib/test_decoding/sql/stats.sql +++ b/contrib/test_decoding/sql/stats.sql @@ -15,16 +15,22 @@ SELECT count(*) FROM pg_logical_slot_get_changes('regression_slot_stats1', NULL, SELECT count(*) FROM pg_logical_slot_get_changes('regression_slot_stats2', NULL, NULL, 'skip-empty-xacts', '1'); SELECT count(*) FROM pg_logical_slot_get_changes('regression_slot_stats3', NULL, NULL, 'skip-empty-xacts', '1'); SELECT pg_stat_force_next_flush(); -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; + +-- total_wal_txns may vary based on the background activity but plugin_sent_txns +-- should always be 1 since the background transactions are always skipped. +-- Filtered bytes would be set only when there's a change that was passed to the +-- plugin but was filtered out. Depending upon the background transactions, +-- filtered bytes may or may not be zero. +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes > 0 AS sent_bytes, plugin_filtered_bytes >= 0 AS filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; RESET logical_decoding_work_mem; -- reset stats for one slot, others should be unaffected SELECT pg_stat_reset_replication_slot('regression_slot_stats1'); -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes > 0 AS sent_bytes, plugin_filtered_bytes >= 0 AS filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; -- reset stats for all slots SELECT pg_stat_reset_replication_slot(NULL); -SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots ORDER BY slot_name; +SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_wal_txns > 0 AS total_wal_txns, total_wal_bytes > 0 AS total_wal_bytes, plugin_sent_txns, plugin_sent_bytes, plugin_filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name; -- verify accessing/resetting stats for non-existent slot does something reasonable SELECT * FROM pg_stat_get_replication_slot('do-not-exist'); @@ -46,8 +52,8 @@ SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count F -- Ensure stats can be repeatedly accessed using the same stats snapshot. See -- https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i%40alap3.anarazel.de BEGIN; -SELECT slot_name FROM pg_stat_replication_slots; -SELECT slot_name FROM pg_stat_replication_slots; +SELECT slot_name, plugin FROM pg_stat_replication_slots; +SELECT slot_name, plugin FROM pg_stat_replication_slots; COMMIT; diff --git a/contrib/test_decoding/t/001_repl_stats.pl b/contrib/test_decoding/t/001_repl_stats.pl index 0de62edb7d8..756fc691ed6 100644 --- a/contrib/test_decoding/t/001_repl_stats.pl +++ b/contrib/test_decoding/t/001_repl_stats.pl @@ -23,10 +23,16 @@ sub test_slot_stats my ($node, $expected, $msg) = @_; + # If there are background transactions which are filtered out by the output + # plugin, plugin_filtered_bytes may be greater than 0. But it's not + # guaranteed that such transactions would be present. my $result = $node->safe_psql( 'postgres', qq[ - SELECT slot_name, total_txns > 0 AS total_txn, - total_bytes > 0 AS total_bytes + SELECT slot_name, total_wal_txns > 0 AS total_txn, + total_wal_bytes > 0 AS total_bytes, + plugin_sent_txns > 0 AS sent_txn, + plugin_sent_bytes > 0 AS sent_bytes, + plugin_filtered_bytes >= 0 AS filtered_bytes FROM pg_stat_replication_slots ORDER BY slot_name]); is($result, $expected, $msg); @@ -65,7 +71,7 @@ $node->poll_query_until( 'postgres', qq[ SELECT count(slot_name) >= 4 FROM pg_stat_replication_slots WHERE slot_name ~ 'regression_slot' - AND total_txns > 0 AND total_bytes > 0; + AND total_wal_txns > 0 AND total_wal_bytes > 0; ]) or die "Timed out while waiting for statistics to be updated"; # Test to drop one of the replication slot and verify replication statistics data is @@ -80,9 +86,9 @@ $node->start; # restart. test_slot_stats( $node, - qq(regression_slot1|t|t -regression_slot2|t|t -regression_slot3|t|t), + qq(regression_slot1|t|t|t|t|t +regression_slot2|t|t|t|t|t +regression_slot3|t|t|t|t|t), 'check replication statistics are updated'); # Test to remove one of the replication slots and adjust @@ -104,8 +110,8 @@ $node->start; # restart. test_slot_stats( $node, - qq(regression_slot1|t|t -regression_slot2|t|t), + qq(regression_slot1|t|t|t|t|t +regression_slot2|t|t|t|t|t), 'check replication statistics after removing the slot file'); # cleanup diff --git a/contrib/test_decoding/test_decoding.c b/contrib/test_decoding/test_decoding.c index 36e77c69e1c..d06f6c3f92b 100644 --- a/contrib/test_decoding/test_decoding.c +++ b/contrib/test_decoding/test_decoding.c @@ -173,6 +173,7 @@ pg_decode_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt, data->only_local = false; ctx->output_plugin_private = data; + ctx->stats = palloc0(sizeof(OutputPluginStats)); opt->output_type = OUTPUT_PLUGIN_TEXTUAL_OUTPUT; opt->receive_rewrites = false; @@ -310,6 +311,7 @@ static void pg_output_begin(LogicalDecodingContext *ctx, TestDecodingData *data, ReorderBufferTXN *txn, bool last_write) { OutputPluginPrepareWrite(ctx, last_write); + ctx->stats->sentTxns++; if (data->include_xids) appendStringInfo(ctx->out, "BEGIN %u", txn->xid); else diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml index b803a819cf1..c02d4a88d57 100644 --- a/doc/src/sgml/logicaldecoding.sgml +++ b/doc/src/sgml/logicaldecoding.sgml @@ -938,6 +938,34 @@ typedef struct OutputPluginOptions needs to have a state, it can use <literal>ctx->output_plugin_private</literal> to store it. </para> + + <para> + The startup callback may initialize <literal>ctx->stats</literal>, + typically as follows, if it chooses to maintain and report statistics + about its activity in <structname>pg_stat_replication_slots</structname>. +<programlisting> +ctx->stats = palloc0(sizeof(OutputPluginStats)); +</programlisting> + where <literal>OutputPluginStats</literal> is defined as follows: +<programlisting> +typedef struct OutputPluginStats +{ + int64 sentTxns; + int64 sentBytes; + int64 filteredBytes; +} OutputPluginStats; +</programlisting> + <literal>sentTxns</literal> is the number of transactions sent downstream + by the output plugin. <literal>sentBytes</literal> is the amount of data, + in bytes, sent downstream by the output plugin. + <literal>filteredBytes</literal> is the size of changes, in bytes, that + are filtered out by the output plugin. + <function>OutputPluginWrite</function> will update + <literal>sentBytes</literal> if <literal>ctx->stats</literal> is + initialized by the output plugin. Function + <literal>ReorderBufferChangeSize</literal> may be used to find the size of + filtered <literal>ReorderBufferChange</literal>. + </para> </sect3> <sect3 id="logicaldecoding-output-plugin-shutdown"> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..fbe03ffd670 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -1545,6 +1545,17 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>plugin</structfield> <type>text</type> + </para> + <para> + The base name of the shared object containing the output plugin this + logical slot is using. This column is same as the one in + <structname>pg_replication_slots</structname>. + </para></entry> + </row> + <row> <entry role="catalog_table_entry"><para role="column_definition"> <structfield>spill_txns</structfield> <type>bigint</type> @@ -1622,19 +1633,19 @@ description | Waiting for a newly initialized WAL file to reach durable storage <row> <entry role="catalog_table_entry"><para role="column_definition"> - <structfield>total_txns</structfield> <type>bigint</type> + <structfield>total_wal_txns</structfield> <type>bigint</type> </para> <para> - Number of decoded transactions sent to the decoding output plugin for - this slot. This counts top-level transactions only, and is not incremented - for subtransactions. Note that this includes the transactions that are - streamed and/or spilled. + Number of decoded transactions from WAL sent to the decoding output + plugin for this slot. This counts top-level transactions only, and is + not incremented for subtransactions. Note that this includes the + transactions that are streamed and/or spilled. </para></entry> </row> <row> <entry role="catalog_table_entry"><para role="column_definition"> - <structfield>total_bytes</structfield><type>bigint</type> + <structfield>total_wal_bytes</structfield><type>bigint</type> </para> <para> Amount of transaction data decoded for sending transactions to the @@ -1644,6 +1655,53 @@ description | Waiting for a newly initialized WAL file to reach durable storage </entry> </row> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>plugin_filtered_bytes</structfield> <type>bigint</type> + </para> + <para> + Amount of changes, from <structfield>total_wal_bytes</structfield>, filtered + out by the output plugin and not sent downstream. Please note that it + does not include the changes filtered before a change is sent to + the output plugin, e.g. the changes filtered by origin. The count is + maintained by the output plugin mentioned in + <structfield>plugin</structfield>. It is NULL when statistics is not + initialized or immediately after a reset or when not maintained by the + output plugin. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>plugin_sent_txns</structfield> <type>bigint</type> + </para> + <para> + Number of decoded transactions sent downstream for this slot. This + counts top-level transactions only, and is not incremented for + subtransactions. These transactions are subset of transctions sent to + the decoding plugin. Hence this count is expected to be lesser than or + equal to <structfield>total_wal_txns</structfield>. The count is maintained + by the output plugin mentioned in <structfield>plugin</structfield>. It + is NULL when statistics is not initialized or immediately after a reset or + when not maintained by the output plugin. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>plugin_sent_bytes</structfield><type>bigint</type> + </para> + <para> + Amount of transaction changes sent downstream for this slot by the + output plugin after applying filtering and converting into its output + format. The count is maintained by the output plugin mentioned in + <structfield>plugin</structfield>. It is NULL when statistics is not + initialized or immediately after a reset or when not maintained by the + output plugin. + </para> + </entry> + </row> + <row> <entry role="catalog_table_entry"><para role="column_definition"> <structfield>stats_reset</structfield> <type>timestamp with time zone</type> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index c77fa0234bb..9e8e32b5849 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -1053,14 +1053,18 @@ CREATE VIEW pg_replication_slots AS CREATE VIEW pg_stat_replication_slots AS SELECT s.slot_name, + r.plugin, s.spill_txns, s.spill_count, s.spill_bytes, s.stream_txns, s.stream_count, s.stream_bytes, - s.total_txns, - s.total_bytes, + s.total_wal_txns, + s.total_wal_bytes, + s.plugin_filtered_bytes, + s.plugin_sent_txns, + s.plugin_sent_bytes, s.stats_reset FROM pg_replication_slots as r, LATERAL pg_stat_get_replication_slot(slot_name) as s diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index c68c0481f42..1435873101f 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -1952,13 +1952,14 @@ void UpdateDecodingStats(LogicalDecodingContext *ctx) { ReorderBuffer *rb = ctx->reorder; + OutputPluginStats *stats = ctx->stats; PgStat_StatReplSlotEntry repSlotStat; /* Nothing to do if we don't have any replication stats to be sent. */ if (rb->spillBytes <= 0 && rb->streamBytes <= 0 && rb->totalBytes <= 0) return; - elog(DEBUG2, "UpdateDecodingStats: updating stats %p %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64, + elog(DEBUG2, "UpdateDecodingStats: updating stats %p %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " (%s) %" PRId64 " %" PRId64 " %" PRId64, rb, rb->spillTxns, rb->spillCount, @@ -1967,7 +1968,11 @@ UpdateDecodingStats(LogicalDecodingContext *ctx) rb->streamCount, rb->streamBytes, rb->totalTxns, - rb->totalBytes); + rb->totalBytes, + stats ? "plugin has stats" : "plugin has no stats", + stats ? stats->sentTxns : 0, + stats ? stats->sentBytes : 0, + stats ? stats->filteredBytes : 0); repSlotStat.spill_txns = rb->spillTxns; repSlotStat.spill_count = rb->spillCount; @@ -1975,8 +1980,17 @@ UpdateDecodingStats(LogicalDecodingContext *ctx) repSlotStat.stream_txns = rb->streamTxns; repSlotStat.stream_count = rb->streamCount; repSlotStat.stream_bytes = rb->streamBytes; - repSlotStat.total_txns = rb->totalTxns; - repSlotStat.total_bytes = rb->totalBytes; + repSlotStat.total_wal_txns = rb->totalTxns; + repSlotStat.total_wal_bytes = rb->totalBytes; + if (stats) + { + repSlotStat.plugin_has_stats = true; + repSlotStat.plugin_sent_txns = stats->sentTxns; + repSlotStat.plugin_sent_bytes = stats->sentBytes; + repSlotStat.plugin_filtered_bytes = stats->filteredBytes; + } + else + repSlotStat.plugin_has_stats = false; pgstat_report_replslot(ctx->slot, &repSlotStat); @@ -1988,6 +2002,12 @@ UpdateDecodingStats(LogicalDecodingContext *ctx) rb->streamBytes = 0; rb->totalTxns = 0; rb->totalBytes = 0; + if (stats) + { + stats->sentTxns = 0; + stats->sentBytes = 0; + stats->filteredBytes = 0; + } } /* diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 25f890ddeed..d2ab41de438 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -89,6 +89,14 @@ LogicalOutputWrite(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xi values[2] = PointerGetDatum(cstring_to_text_with_len(ctx->out->data, ctx->out->len)); tuplestore_putvalues(p->tupstore, p->tupdesc, values, nulls); + + /* + * If output plugin has chosen to maintain its stats, update the amount of + * data sent downstream. + */ + if (ctx->stats) + ctx->stats->sentBytes += ctx->out->len + sizeof(XLogRecPtr) + sizeof(TransactionId); + p->returned_rows++; } diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c index a5e165fb123..840deb5a3b7 100644 --- a/src/backend/replication/logical/reorderbuffer.c +++ b/src/backend/replication/logical/reorderbuffer.c @@ -310,7 +310,6 @@ static void ReorderBufferToastAppendChunk(ReorderBuffer *rb, ReorderBufferTXN *t * memory accounting * --------------------------------------- */ -static Size ReorderBufferChangeSize(ReorderBufferChange *change); static void ReorderBufferChangeMemoryUpdate(ReorderBuffer *rb, ReorderBufferChange *change, ReorderBufferTXN *txn, @@ -4436,7 +4435,7 @@ ReorderBufferStreamTXN(ReorderBuffer *rb, ReorderBufferTXN *txn) /* * Size of a change in memory. */ -static Size +Size ReorderBufferChangeSize(ReorderBufferChange *change) { Size sz = sizeof(ReorderBufferChange); diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c index 92eb17049c3..f87ab5e1d4b 100644 --- a/src/backend/replication/pgoutput/pgoutput.c +++ b/src/backend/replication/pgoutput/pgoutput.c @@ -450,6 +450,7 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt, ALLOCSET_SMALL_SIZES); ctx->output_plugin_private = data; + ctx->stats = palloc0(sizeof(OutputPluginStats)); /* This plugin uses binary protocol. */ opt->output_type = OUTPUT_PLUGIN_BINARY_OUTPUT; @@ -591,6 +592,7 @@ pgoutput_send_begin(LogicalDecodingContext *ctx, ReorderBufferTXN *txn) OutputPluginPrepareWrite(ctx, !send_replication_origin); logicalrep_write_begin(ctx->out, txn); txndata->sent_begin_txn = true; + ctx->stats->sentTxns++; send_repl_origin(ctx, txn->origin_id, txn->origin_lsn, send_replication_origin); @@ -1469,7 +1471,10 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, TupleTableSlot *new_slot = NULL; if (!is_publishable_relation(relation)) + { + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); return; + } /* * Remember the xid for the change in streaming mode. We need to send xid @@ -1487,15 +1492,24 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, { case REORDER_BUFFER_CHANGE_INSERT: if (!relentry->pubactions.pubinsert) + { + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); return; + } break; case REORDER_BUFFER_CHANGE_UPDATE: if (!relentry->pubactions.pubupdate) + { + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); return; + } break; case REORDER_BUFFER_CHANGE_DELETE: if (!relentry->pubactions.pubdelete) + { + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); return; + } /* * This is only possible if deletes are allowed even when replica @@ -1505,6 +1519,7 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, if (!change->data.tp.oldtuple) { elog(DEBUG1, "didn't send DELETE change because of missing oldtuple"); + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); return; } break; @@ -1560,7 +1575,10 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, * of the row filter for old and new tuple. */ if (!pgoutput_row_filter(targetrel, old_slot, &new_slot, relentry, &action)) + { + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); goto cleanup; + } /* * Send BEGIN if we haven't yet. @@ -1688,6 +1706,9 @@ pgoutput_truncate(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, change->data.truncate.restart_seqs); OutputPluginWrite(ctx, true); } + else + ctx->stats->filteredBytes += ReorderBufferChangeSize(change); + MemoryContextSwitchTo(old); MemoryContextReset(data->context); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 59822f22b8d..d9217ce49aa 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1573,6 +1573,13 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid, /* output previously gathered data in a CopyData packet */ pq_putmessage_noblock(PqMsg_CopyData, ctx->out->data, ctx->out->len); + /* + * If output plugin maintains statistics, update the amount of data sent + * downstream. + */ + if (ctx->stats) + ctx->stats->sentBytes += ctx->out->len + 1; /* +1 for the 'd' */ + CHECK_FOR_INTERRUPTS(); /* Try to flush pending output to the client */ diff --git a/src/backend/utils/activity/pgstat_replslot.c b/src/backend/utils/activity/pgstat_replslot.c index ccfb11c49bf..895940f4eb9 100644 --- a/src/backend/utils/activity/pgstat_replslot.c +++ b/src/backend/utils/activity/pgstat_replslot.c @@ -94,8 +94,15 @@ pgstat_report_replslot(ReplicationSlot *slot, const PgStat_StatReplSlotEntry *re REPLSLOT_ACC(stream_txns); REPLSLOT_ACC(stream_count); REPLSLOT_ACC(stream_bytes); - REPLSLOT_ACC(total_txns); - REPLSLOT_ACC(total_bytes); + REPLSLOT_ACC(total_wal_txns); + REPLSLOT_ACC(total_wal_bytes); + statent->plugin_has_stats = repSlotStat->plugin_has_stats; + if (repSlotStat->plugin_has_stats) + { + REPLSLOT_ACC(plugin_sent_txns); + REPLSLOT_ACC(plugin_sent_bytes); + REPLSLOT_ACC(plugin_filtered_bytes); + } #undef REPLSLOT_ACC pgstat_unlock_entry(entry_ref); diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..588b49059b2 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -2100,7 +2100,7 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS) Datum pg_stat_get_replication_slot(PG_FUNCTION_ARGS) { -#define PG_STAT_GET_REPLICATION_SLOT_COLS 10 +#define PG_STAT_GET_REPLICATION_SLOT_COLS 13 text *slotname_text = PG_GETARG_TEXT_P(0); NameData slotname; TupleDesc tupdesc; @@ -2125,11 +2125,17 @@ pg_stat_get_replication_slot(PG_FUNCTION_ARGS) INT8OID, -1, 0); TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stream_bytes", INT8OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 8, "total_txns", + TupleDescInitEntry(tupdesc, (AttrNumber) 8, "total_wal_txns", INT8OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 9, "total_bytes", + TupleDescInitEntry(tupdesc, (AttrNumber) 9, "total_wal_bytes", INT8OID, -1, 0); - TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stats_reset", + TupleDescInitEntry(tupdesc, (AttrNumber) 10, "plugin_filtered_bytes", + INT8OID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 11, "plugin_sent_txns", + INT8OID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 12, "plugin_sent_bytes", + INT8OID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset", TIMESTAMPTZOID, -1, 0); BlessTupleDesc(tupdesc); @@ -2152,13 +2158,25 @@ pg_stat_get_replication_slot(PG_FUNCTION_ARGS) values[4] = Int64GetDatum(slotent->stream_txns); values[5] = Int64GetDatum(slotent->stream_count); values[6] = Int64GetDatum(slotent->stream_bytes); - values[7] = Int64GetDatum(slotent->total_txns); - values[8] = Int64GetDatum(slotent->total_bytes); + values[7] = Int64GetDatum(slotent->total_wal_txns); + values[8] = Int64GetDatum(slotent->total_wal_bytes); + if (slotent->plugin_has_stats) + { + values[9] = Int64GetDatum(slotent->plugin_filtered_bytes); + values[10] = Int64GetDatum(slotent->plugin_sent_txns); + values[11] = Int64GetDatum(slotent->plugin_sent_bytes); + } + else + { + nulls[9] = true; + nulls[10] = true; + nulls[11] = true; + } if (slotent->stat_reset_timestamp == 0) - nulls[9] = true; + nulls[12] = true; else - values[9] = TimestampTzGetDatum(slotent->stat_reset_timestamp); + values[12] = TimestampTzGetDatum(slotent->stat_reset_timestamp); /* Returns the record as Datum */ PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls))); diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 01eba3b5a19..9e4f6620214 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5687,9 +5687,9 @@ { oid => '6169', descr => 'statistics: information about replication slot', proname => 'pg_stat_get_replication_slot', provolatile => 's', proparallel => 'r', prorettype => 'record', proargtypes => 'text', - proallargtypes => '{text,text,int8,int8,int8,int8,int8,int8,int8,int8,timestamptz}', - proargmodes => '{i,o,o,o,o,o,o,o,o,o,o}', - proargnames => '{slot_name,slot_name,spill_txns,spill_count,spill_bytes,stream_txns,stream_count,stream_bytes,total_txns,total_bytes,stats_reset}', + proallargtypes => '{text,text,int8,int8,int8,int8,int8,int8,int8,int8,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o}', + proargnames => '{slot_name,slot_name,spill_txns,spill_count,spill_bytes,stream_txns,stream_count,stream_bytes,total_wal_txns,total_wal_bytes,plugin_filtered_bytes,plugin_sent_txns,plugin_sent_bytes,stats_reset}', prosrc => 'pg_stat_get_replication_slot' }, { oid => '6230', descr => 'statistics: check if a stats object exists', diff --git a/src/include/pgstat.h b/src/include/pgstat.h index e4a59a30b8c..7c680c21f55 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -394,8 +394,12 @@ typedef struct PgStat_StatReplSlotEntry PgStat_Counter stream_txns; PgStat_Counter stream_count; PgStat_Counter stream_bytes; - PgStat_Counter total_txns; - PgStat_Counter total_bytes; + PgStat_Counter total_wal_txns; + PgStat_Counter total_wal_bytes; + bool plugin_has_stats; + PgStat_Counter plugin_sent_txns; + PgStat_Counter plugin_sent_bytes; + PgStat_Counter plugin_filtered_bytes; TimestampTz stat_reset_timestamp; } PgStat_StatReplSlotEntry; diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index 2e562bee5a9..010c59f783d 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -52,6 +52,7 @@ typedef struct LogicalDecodingContext OutputPluginCallbacks callbacks; OutputPluginOptions options; + OutputPluginStats *stats; /* * User specified options diff --git a/src/include/replication/output_plugin.h b/src/include/replication/output_plugin.h index 8d4d5b71887..02018f0593c 100644 --- a/src/include/replication/output_plugin.h +++ b/src/include/replication/output_plugin.h @@ -29,6 +29,19 @@ typedef struct OutputPluginOptions bool receive_rewrites; } OutputPluginOptions; +/* + * Statistics about the transactions decoded and sent downstream by the output + * plugin. + */ +typedef struct OutputPluginStats +{ + int64 sentTxns; /* number of transactions decoded and sent + * downstream */ + int64 sentBytes; /* amount of data decoded and sent downstream */ + int64 filteredBytes; /* amount of data from reoder buffer that was + * filtered out by the output plugin */ +} OutputPluginStats; + /* * Type of the shared library symbol _PG_output_plugin_init that is looked up * when loading an output plugin shared library. diff --git a/src/include/replication/reorderbuffer.h b/src/include/replication/reorderbuffer.h index 91dc7e5e448..f5a4c35995c 100644 --- a/src/include/replication/reorderbuffer.h +++ b/src/include/replication/reorderbuffer.h @@ -715,6 +715,7 @@ extern void ReorderBufferFreeRelids(ReorderBuffer *rb, Oid *relids); extern void ReorderBufferQueueChange(ReorderBuffer *rb, TransactionId xid, XLogRecPtr lsn, ReorderBufferChange *change, bool toast_insert); +extern Size ReorderBufferChangeSize(ReorderBufferChange *change); extern void ReorderBufferQueueMessage(ReorderBuffer *rb, TransactionId xid, Snapshot snap, XLogRecPtr lsn, bool transactional, const char *prefix, diff --git a/src/test/recovery/t/006_logical_decoding.pl b/src/test/recovery/t/006_logical_decoding.pl index 2137c4e5e30..92e42bec6a9 100644 --- a/src/test/recovery/t/006_logical_decoding.pl +++ b/src/test/recovery/t/006_logical_decoding.pl @@ -212,10 +212,10 @@ my $stats_test_slot2 = 'logical_slot'; # Stats exist for stats test slot 1 is( $node_primary->safe_psql( 'postgres', - qq(SELECT total_bytes > 0, stats_reset IS NULL FROM pg_stat_replication_slots WHERE slot_name = '$stats_test_slot1') + qq(SELECT total_wal_bytes > 0, plugin_sent_bytes > 0, stats_reset IS NULL FROM pg_stat_replication_slots WHERE slot_name = '$stats_test_slot1') ), - qq(t|t), - qq(Total bytes is > 0 and stats_reset is NULL for slot '$stats_test_slot1'.) + qq(t|t|t), + qq(Total bytes and plugin sent bytes are both > 0 and stats_reset is NULL for slot '$stats_test_slot1'.) ); # Do reset of stats for stats test slot 1 @@ -233,10 +233,10 @@ $node_primary->safe_psql('postgres', is( $node_primary->safe_psql( 'postgres', - qq(SELECT stats_reset > '$reset1'::timestamptz, total_bytes = 0 FROM pg_stat_replication_slots WHERE slot_name = '$stats_test_slot1') + qq(SELECT stats_reset > '$reset1'::timestamptz, total_wal_bytes = 0, plugin_sent_bytes is NULL FROM pg_stat_replication_slots WHERE slot_name = '$stats_test_slot1') ), - qq(t|t), - qq(Check that reset timestamp is later after the second reset of stats for slot '$stats_test_slot1' and confirm total_bytes was set to 0.) + qq(t|t|t), + qq(Check that reset timestamp is later after the second reset of stats for slot '$stats_test_slot1' and confirm total_wal_bytes and plugin_sent_bytes were set to 0 and NULL respectively.) ); # Check that test slot 2 has NULL in reset timestamp diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.pl index c9c182892cf..c8577794eec 100644 --- a/src/test/recovery/t/035_standby_logical_decoding.pl +++ b/src/test/recovery/t/035_standby_logical_decoding.pl @@ -575,7 +575,7 @@ $node_primary->safe_psql('testdb', qq[INSERT INTO decoding_test(x,y) SELECT 100,'100';]); $node_standby->poll_query_until('testdb', - qq[SELECT total_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot'] + qq[SELECT total_wal_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot'] ) or die "replication slot stats of vacuum_full_activeslot not updated"; # This should trigger the conflict @@ -603,7 +603,7 @@ ok( $stderr =~ # Ensure that replication slot stats are not removed after invalidation. is( $node_standby->safe_psql( 'testdb', - qq[SELECT total_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot'] + qq[SELECT total_wal_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot'] ), 't', 'replication slot stats not removed after invalidation'); diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..2a401552a7a 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -2132,17 +2132,21 @@ pg_stat_replication| SELECT s.pid, JOIN pg_stat_get_wal_senders() w(pid, state, sent_lsn, write_lsn, flush_lsn, replay_lsn, write_lag, flush_lag, replay_lag, sync_priority, sync_state, reply_time) ON ((s.pid = w.pid))) LEFT JOIN pg_authid u ON ((s.usesysid = u.oid))); pg_stat_replication_slots| SELECT s.slot_name, + r.plugin, s.spill_txns, s.spill_count, s.spill_bytes, s.stream_txns, s.stream_count, s.stream_bytes, - s.total_txns, - s.total_bytes, + s.total_wal_txns, + s.total_wal_bytes, + s.plugin_filtered_bytes, + s.plugin_sent_txns, + s.plugin_sent_bytes, s.stats_reset FROM pg_replication_slots r, - LATERAL pg_stat_get_replication_slot((r.slot_name)::text) s(slot_name, spill_txns, spill_count, spill_bytes, stream_txns, stream_count, stream_bytes, total_txns, total_bytes, stats_reset) + LATERAL pg_stat_get_replication_slot((r.slot_name)::text) s(slot_name, spill_txns, spill_count, spill_bytes, stream_txns, stream_count, stream_bytes, total_wal_txns, total_wal_bytes, plugin_filtered_bytes, plugin_sent_txns, plugin_sent_bytes, stats_reset) WHERE (r.datoid IS NOT NULL); pg_stat_slru| SELECT name, blks_zeroed, diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl index ca55d8df50d..a7bee7fe5e4 100644 --- a/src/test/subscription/t/001_rep_changes.pl +++ b/src/test/subscription/t/001_rep_changes.pl @@ -124,6 +124,9 @@ $result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM tab_ins"); is($result, qq(1002), 'check initial data was copied to subscriber'); +my $initial_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT coalesce(plugin_filtered_bytes, 0) FROM pg_stat_replication_slots WHERE slot_name = 'tap_sub'"); + $node_publisher->safe_psql('postgres', "INSERT INTO tab_ins SELECT generate_series(1,50)"); $node_publisher->safe_psql('postgres', "DELETE FROM tab_ins WHERE a > 20"); @@ -157,6 +160,14 @@ $node_publisher->safe_psql('postgres', $node_publisher->wait_for_catchup('tap_sub'); +# Verify that plugin_filtered_bytes increases due to filtered update and delete +# operations on tab_ins. We cannot test the exact value since it may include +# changes from other concurrent transactions. +my $final_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT plugin_filtered_bytes FROM pg_stat_replication_slots WHERE slot_name = 'tap_sub'"); +cmp_ok($final_filtered_bytes, '>', $initial_filtered_bytes, + 'plugin_filtered_bytes increased after DML filtering'); + $result = $node_subscriber->safe_psql('postgres', "SELECT count(*), min(a), max(a) FROM tab_ins"); is($result, qq(1052|1|1002), 'check replicated inserts on subscriber'); diff --git a/src/test/subscription/t/010_truncate.pl b/src/test/subscription/t/010_truncate.pl index 3d16c2a800d..c41ad317221 100644 --- a/src/test/subscription/t/010_truncate.pl +++ b/src/test/subscription/t/010_truncate.pl @@ -69,6 +69,9 @@ $node_subscriber->safe_psql('postgres', # Wait for initial sync of all subscriptions $node_subscriber->wait_for_subscription_sync; +my $initial_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT coalesce(plugin_filtered_bytes, 0) FROM pg_stat_replication_slots WHERE slot_name = 'sub2'"); + # insert data to truncate $node_subscriber->safe_psql('postgres', @@ -98,6 +101,16 @@ $node_publisher->wait_for_catchup('sub1'); $result = $node_subscriber->safe_psql('postgres', "SELECT nextval('seq1')"); is($result, qq(101), 'truncate restarted identities'); +# All the DMLs above happen on tables that are subscribed to by sub1 and not +# sub2. plugin_filtered_bytes should get incremented for replication slot +# corresponding to the subscription sub2. We can not test the exact value of +# plugin_filtered_bytes because the counter is affected by background activity. +my $final_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT plugin_filtered_bytes FROM pg_stat_replication_slots WHERE slot_name = 'sub2'"); +cmp_ok($final_filtered_bytes, '>', $initial_filtered_bytes, + 'plugin_filtered_bytes increased after publication level filtering'); +$initial_filtered_bytes = $final_filtered_bytes; + # test publication that does not replicate truncate $node_subscriber->safe_psql('postgres', @@ -107,6 +120,13 @@ $node_publisher->safe_psql('postgres', "TRUNCATE tab2"); $node_publisher->wait_for_catchup('sub2'); +# Truncate changes are filtered out at publication level itself. Make sure that +# the plugin_filtered_bytes is incremented. +$final_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT plugin_filtered_bytes FROM pg_stat_replication_slots WHERE slot_name = 'sub2'"); +cmp_ok($final_filtered_bytes, '>', $initial_filtered_bytes, + 'plugin_filtered_bytes increased after truncate filtering'); + $result = $node_subscriber->safe_psql('postgres', "SELECT count(*), min(a), max(a) FROM tab2"); is($result, qq(3|1|3), 'truncate not replicated'); diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl index e2c83670053..039bf5ff5a0 100644 --- a/src/test/subscription/t/028_row_filter.pl +++ b/src/test/subscription/t/028_row_filter.pl @@ -579,6 +579,9 @@ is($result, qq(3|6), # commands are for testing normal logical replication behavior. # # test row filter (INSERT, UPDATE, DELETE) +my $initial_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT coalesce(plugin_filtered_bytes, 0) FROM pg_stat_replication_slots WHERE slot_name = 'tap_sub'"); + $node_publisher->safe_psql('postgres', "INSERT INTO tab_rowfilter_1 (a, b) VALUES (800, 'test 800')"); $node_publisher->safe_psql('postgres', @@ -612,6 +615,14 @@ $node_publisher->safe_psql('postgres', $node_publisher->wait_for_catchup($appname); +# The changes which do not pass the row filter will be filtered. Make sure that +# the plugin_filtered_bytes reflects that. We can not test the exact value of +# plugin_filtered_bytes since it is affected by background activity. +my $final_filtered_bytes = $node_publisher->safe_psql('postgres', + "SELECT plugin_filtered_bytes FROM pg_stat_replication_slots WHERE slot_name = 'tap_sub'"); +cmp_ok($final_filtered_bytes, '>', $initial_filtered_bytes, + 'plugin_filtered_bytes increased after row filtering'); + # Check expected replicated rows for tab_rowfilter_2 # tap_pub_1 filter is: (c % 2 = 0) # tap_pub_2 filter is: (c % 3 = 0) diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 37f26f6c6b7..02f984770f7 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -1830,6 +1830,7 @@ OuterJoinClauseInfo OutputPluginCallbacks OutputPluginOptions OutputPluginOutputType +OutputPluginStats OverridingKind PACE_HEADER PACL base-commit: 902c08887aa183100b161ef48f1a2434af079213 -- 2.34.1
From 4d3e61b362b794a99ca72cc8107d2ed72020fa04 Mon Sep 17 00:00:00 2001 From: Ashutosh Bapat <[email protected]> Date: Thu, 25 Sep 2025 10:15:43 +0530 Subject: [PATCH 2/2] Address review comments from Bertrand When the stats are not enabled, we should reset the plugin stats to 0, rather than carrying over the stale stats from the time when the plugin was supporting the stats. This does not matter if the plugin continues not to support statistics forever. But in case it was supporting the stats once, discontinued doing so at some point in time and then starts supporting the stats later, accumulating the new stats based on the earlier accumulated stats could be misleading. Author: Ashutosh Bapat --- doc/src/sgml/monitoring.sgml | 10 +++++----- src/backend/utils/activity/pgstat_replslot.c | 7 +++++++ 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index fbe03ffd670..4d414d71742 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -1663,7 +1663,7 @@ description | Waiting for a newly initialized WAL file to reach durable storage Amount of changes, from <structfield>total_wal_bytes</structfield>, filtered out by the output plugin and not sent downstream. Please note that it does not include the changes filtered before a change is sent to - the output plugin, e.g. the changes filtered by origin. The count is + the output plugin, e.g. the changes filtered by origin. The counter is maintained by the output plugin mentioned in <structfield>plugin</structfield>. It is NULL when statistics is not initialized or immediately after a reset or when not maintained by the @@ -1678,9 +1678,9 @@ description | Waiting for a newly initialized WAL file to reach durable storage <para> Number of decoded transactions sent downstream for this slot. This counts top-level transactions only, and is not incremented for - subtransactions. These transactions are subset of transctions sent to - the decoding plugin. Hence this count is expected to be lesser than or - equal to <structfield>total_wal_txns</structfield>. The count is maintained + subtransactions. These transactions are subset of transactions sent to + the decoding plugin. Hence this count is expected to be less than or + equal to <structfield>total_wal_txns</structfield>. The counter is maintained by the output plugin mentioned in <structfield>plugin</structfield>. It is NULL when statistics is not initialized or immediately after a reset or when not maintained by the output plugin. @@ -1694,7 +1694,7 @@ description | Waiting for a newly initialized WAL file to reach durable storage <para> Amount of transaction changes sent downstream for this slot by the output plugin after applying filtering and converting into its output - format. The count is maintained by the output plugin mentioned in + format. The counter is maintained by the output plugin mentioned in <structfield>plugin</structfield>. It is NULL when statistics is not initialized or immediately after a reset or when not maintained by the output plugin. diff --git a/src/backend/utils/activity/pgstat_replslot.c b/src/backend/utils/activity/pgstat_replslot.c index 895940f4eb9..3e486fd28e4 100644 --- a/src/backend/utils/activity/pgstat_replslot.c +++ b/src/backend/utils/activity/pgstat_replslot.c @@ -88,6 +88,7 @@ pgstat_report_replslot(ReplicationSlot *slot, const PgStat_StatReplSlotEntry *re /* Update the replication slot statistics */ #define REPLSLOT_ACC(fld) statent->fld += repSlotStat->fld +#define REPLSLOT_SET_TO_ZERO(fld) statent->fld = 0 REPLSLOT_ACC(spill_txns); REPLSLOT_ACC(spill_count); REPLSLOT_ACC(spill_bytes); @@ -103,6 +104,12 @@ pgstat_report_replslot(ReplicationSlot *slot, const PgStat_StatReplSlotEntry *re REPLSLOT_ACC(plugin_sent_bytes); REPLSLOT_ACC(plugin_filtered_bytes); } + else + { + REPLSLOT_SET_TO_ZERO(plugin_sent_txns); + REPLSLOT_SET_TO_ZERO(plugin_sent_bytes); + REPLSLOT_SET_TO_ZERO(plugin_filtered_bytes); + } #undef REPLSLOT_ACC pgstat_unlock_entry(entry_ref); -- 2.34.1
