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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
| commit | 46651ce6fe013220ed397add242004d764fc0153 (patch) | |
| tree | 6e5299f990f88e60174a1d3ae6e48eedd2688b2b /doc/src/sgml/test-decoding.sgml | |
| parent | Initial commit. (diff) | |
| download | postgresql-14-46651ce6fe013220ed397add242004d764fc0153.tar.xz postgresql-14-46651ce6fe013220ed397add242004d764fc0153.zip | |
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/test-decoding.sgml')
| -rw-r--r-- | doc/src/sgml/test-decoding.sgml | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/doc/src/sgml/test-decoding.sgml b/doc/src/sgml/test-decoding.sgml new file mode 100644 index 0000000..cf736bd --- /dev/null +++ b/doc/src/sgml/test-decoding.sgml @@ -0,0 +1,64 @@ +<!-- doc/src/sgml/test-decoding.sgml --> + +<sect1 id="test-decoding" xreflabel="test_decoding"> + <title>test_decoding</title> + + <indexterm zone="test-decoding"> + <primary>test_decoding</primary> + </indexterm> + + <para> + <filename>test_decoding</filename> is an example of a logical decoding + output plugin. It doesn't do anything especially useful, but can serve as + a starting point for developing your own output plugin. + </para> + + <para> + <filename>test_decoding</filename> receives WAL through the logical decoding + mechanism and decodes it into text representations of the operations + performed. + </para> + + <para> + Typical output from this plugin, used over the SQL logical decoding + interface, might be: + +<programlisting> +postgres=# SELECT * FROM pg_logical_slot_get_changes('test_slot', NULL, NULL, 'include-xids', '0'); + lsn | xid | data +-----------+-----+-------------------------------------------------- + 0/16D30F8 | 691 | BEGIN + 0/16D32A0 | 691 | table public.data: INSERT: id[int4]:2 data[text]:'arg' + 0/16D32A0 | 691 | table public.data: INSERT: id[int4]:3 data[text]:'demo' + 0/16D32A0 | 691 | COMMIT + 0/16D32D8 | 692 | BEGIN + 0/16D3398 | 692 | table public.data: DELETE: id[int4]:2 + 0/16D3398 | 692 | table public.data: DELETE: id[int4]:3 + 0/16D3398 | 692 | COMMIT +(8 rows) +</programlisting> + </para> + +<para> + We can also get the changes of the in-progress transaction, and the typical + output might be: + +<programlisting> +postgres[33712]=#* SELECT * FROM pg_logical_slot_get_changes('test_slot', NULL, NULL, 'stream-changes', '1'); + lsn | xid | data +-----------+-----+-------------------------------------------------- + 0/16B21F8 | 503 | opening a streamed block for transaction TXN 503 + 0/16B21F8 | 503 | streaming change for TXN 503 + 0/16B2300 | 503 | streaming change for TXN 503 + 0/16B2408 | 503 | streaming change for TXN 503 + 0/16BEBA0 | 503 | closing a streamed block for transaction TXN 503 + 0/16B21F8 | 503 | opening a streamed block for transaction TXN 503 + 0/16BECA8 | 503 | streaming change for TXN 503 + 0/16BEDB0 | 503 | streaming change for TXN 503 + 0/16BEEB8 | 503 | streaming change for TXN 503 + 0/16BEBA0 | 503 | closing a streamed block for transaction TXN 503 +(10 rows) +</programlisting> + </para> + +</sect1> |