Revert "Logical decoding of sequences"

This reverts a sequence of commits, implementing features related to
logical decoding and replication of sequences:

 - 0da92dc530c9251735fc70b20cd004d9630a1266
 - 80901b32913ffa59bf157a4d88284b2b3a7511d9
 - b779d7d8fdae088d70da5ed9fcd8205035676df3
 - d5ed9da41d96988d905b49bebb273a9b2d6e2915
 - a180c2b34de0989269fdb819bff241a249bf5380
 - 75b1521dae1ff1fde17fda2e30e591f2e5d64b6a
 - 2d2232933b02d9396113662e44dca5f120d6830e
 - 002c9dd97a0c874fd1693a570383e2dd38cd40d5
 - 05843b1aa49df2ecc9b97c693b755bd1b6f856a9

The implementation has issues, mostly due to combining transactional and
non-transactional behavior of sequences. It's not clear how this could
be fixed, but it'll require reworking significant part of the patch.

Discussion: https://postgr.es/m/95345a19-d508-63d1-860a-f5c2f41e8d40@enterprisedb.com

1 files changed, 5 insertions, 60 deletions

diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml
index a6ea6ff3fcf..8b2c31a87fa 100644
--- a/doc/src/sgml/logicaldecoding.sgml
+++ b/doc/src/sgml/logicaldecoding.sgml
@@ -458,7 +458,6 @@ typedef struct OutputPluginCallbacks
     LogicalDecodeTruncateCB truncate_cb;
     LogicalDecodeCommitCB commit_cb;
     LogicalDecodeMessageCB message_cb;
-    LogicalDecodeSequenceCB sequence_cb;
     LogicalDecodeFilterByOriginCB filter_by_origin_cb;
     LogicalDecodeShutdownCB shutdown_cb;
     LogicalDecodeFilterPrepareCB filter_prepare_cb;
@@ -473,7 +472,6 @@ typedef struct OutputPluginCallbacks
     LogicalDecodeStreamCommitCB stream_commit_cb;
     LogicalDecodeStreamChangeCB stream_change_cb;
     LogicalDecodeStreamMessageCB stream_message_cb;
-    LogicalDecodeStreamSequenceCB stream_sequence_cb;
     LogicalDecodeStreamTruncateCB stream_truncate_cb;
 } OutputPluginCallbacks;
 
@@ -483,11 +481,9 @@ typedef void (*LogicalOutputPluginInit) (struct OutputPluginCallbacks *cb);
      and <function>commit_cb</function> callbacks are required,
      while <function>startup_cb</function>,
      <function>filter_by_origin_cb</function>, <function>truncate_cb</function>,
-     <function>sequence_cb</function>, and <function>shutdown_cb</function> are
-     optional. If <function>truncate_cb</function> is not set but a
+     and <function>shutdown_cb</function> are optional.
+     If <function>truncate_cb</function> is not set but a
      <command>TRUNCATE</command> is to be decoded, the action will be ignored.
-     Similarly, if <function>sequence_cb</function> is not set and a sequence
-     change is to be decoded, the action will be ignored.
     </para>
 
     <para>
@@ -496,8 +492,7 @@ typedef void (*LogicalOutputPluginInit) (struct OutputPluginCallbacks *cb);
      <function>stream_stop_cb</function>, <function>stream_abort_cb</function>,
      <function>stream_commit_cb</function>, <function>stream_change_cb</function>,
      and <function>stream_prepare_cb</function>
-     are required, while <function>stream_message_cb</function>,
-     <function>stream_sequence_cb</function>, and
+     are required, while <function>stream_message_cb</function> and
      <function>stream_truncate_cb</function> are optional.
     </para>
 
@@ -813,35 +808,6 @@ typedef void (*LogicalDecodeMessageCB) (struct LogicalDecodingContext *ctx,
      </para>
     </sect3>
 
-    <sect3 id="logicaldecoding-output-plugin-sequence">
-     <title>Sequence Callback</title>
-
-     <para>
-      The optional <function>sequence_cb</function> callback is called for
-      actions that update a sequence value.
-<programlisting>
-typedef void (*LogicalDecodeSequenceCB) (struct LogicalDecodingContext *ctx,
-                                         ReorderBufferTXN *txn,
-                                         XLogRecPtr sequence_lsn,
-                                         Relation rel,
-                                         bool transactional,
-                                         int64 last_value,
-                                         int64 log_cnt,
-                                         bool is_called);
-</programlisting>
-      The <parameter>txn</parameter> parameter contains meta information about
-      the transaction the sequence change is part of. Note however that for
-      non-transactional increments, the transaction may be either NULL or not
-      NULL, depending on if the transaction already has an XID assigned.
-      The <parameter>sequence_lsn</parameter> has the WAL location of the
-      sequence update. <parameter>transactional</parameter> says if the
-      sequence has to be replayed as part of the transaction or directly.
-
-      The <parameter>last_value</parameter>, <parameter>log_cnt</parameter> and
-      <parameter>is_called</parameter> parameters describe the sequence change.
-     </para>
-    </sect3>
-
     <sect3 id="logicaldecoding-output-plugin-filter-prepare">
      <title>Prepare Filter Callback</title>
 
@@ -1051,26 +1017,6 @@ typedef void (*LogicalDecodeStreamMessageCB) (struct LogicalDecodingContext *ctx
      </para>
     </sect3>
 
-    <sect3 id="logicaldecoding-output-plugin-stream-sequence">
-     <title>Stream Sequence Callback</title>
-     <para>
-      The optional <function>stream_sequence_cb</function> callback is called
-      for actions that change a sequence in a block of streamed changes
-      (demarcated by <function>stream_start_cb</function> and
-      <function>stream_stop_cb</function> calls).
-<programlisting>
-typedef void (*LogicalDecodeStreamSequenceCB) (struct LogicalDecodingContext *ctx,
-                                               ReorderBufferTXN *txn,
-                                               XLogRecPtr sequence_lsn,
-                                               Relation rel,
-                                               bool transactional,
-                                               int64 last_value,
-                                               int64 log_cnt,
-                                               bool is_called);
-</programlisting>
-     </para>
-    </sect3>
-
     <sect3 id="logicaldecoding-output-plugin-stream-truncate">
      <title>Stream Truncate Callback</title>
      <para>
@@ -1251,9 +1197,8 @@ OutputPluginWrite(ctx, true);
     in-progress transactions. There are multiple required streaming callbacks
     (<function>stream_start_cb</function>, <function>stream_stop_cb</function>,
     <function>stream_abort_cb</function>, <function>stream_commit_cb</function>
-    and <function>stream_change_cb</function>) and multiple optional callbacks
-    (<function>stream_message_cb</function>, <function>stream_sequence_cb</function>,
-    and <function>stream_truncate_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).