7 Commits (2da74d8d6400975bf73fb0df97c3943ad3ed9a36)

Author	SHA1	Message	Date
Masahiko Sawada	072ee847ad	Skip logical decoding of already-aborted transactions. ... Previously, transaction aborts were detected concurrently only during system catalog scans while replaying a transaction in streaming mode. This commit adds an additional CLOG lookup to check the transaction status, allowing the logical decoding to skip changes also when it doesn't touch system catalogs, if the transaction is already aborted. This optimization enhances logical decoding performance, especially for large transactions that have already been rolled back, as it avoids unnecessary disk or network I/O. To avoid potential slowdowns caused by frequent CLOG lookups for small transactions (most of which commit), the CLOG lookup is performed only for large transactions before eviction. The performance benchmark results showed there is not noticeable performance regression due to CLOG lookups. Reviewed-by: Amit Kapila, Peter Smith, Vignesh C, Ajin Cherian Reviewed-by: Dilip Kumar, Andres Freund Discussion: https://postgr.es/m/CAD21AoDht9Pz_DFv_R2LqBTBbO4eGrpa9Vojmt5z5sEx3XwD7A@mail.gmail.com	11 months ago
Amit Kapila	d759c1a0b8	Stabilize the test added by commit 022564f60c. ... The test was unstable in branches 14 and 15 as we were relying on the number of changes in the table having a toast column to start streaming. On branches >= 16, we have a GUC debug_logical_replication_streaming which can stream each change, so the test was stable in those branches. Change the test to use PREPARE TRANSACTION as that should make the result consistent and test the code changed in 022564f60c. Reported-by: Daniel Gustafsson as per buildfarm Author: Hou Zhijie, Amit Kapila Backpatch-through: 14 Discussion: https://postgr.es/m/8C2F86AA-981E-4803-B14D-E264C0255330@yesql.se	1 year ago
Amit Kapila	022564f60c	Fix fetching default toast value during decoding of in-progress transactions. ... During logical decoding of in-progress transactions, we perform the toast table scan while fetching the default toast value for an attribute. We forgot to initialize the flag during this scan to indicate that the system table scan is in progress. We need this flag to ensure that during logical decoding we never directly access the tableam or heap APIs because we check for concurrent aborts only in systable_* APIs. Reported-by: Alexander Lakhin Author: Takeshi Ideriha, Hou Zhijie Reviewed-by: Amit Kapila, Hou Zhijie Backpatch-through: 14 Discussion: https://postgr.es/m/18641-6687273b7f15269d@postgresql.org	1 year ago
Masahiko Sawada	52f1d6730b	Fix memory counter update in ReorderBuffer. ... Commit 5bec1d6bc5 changed the memory usage updates of the ReorderBufferTXN to zero all at once by subtracting txn->size, rather than updating it for each change. However, if TOAST reconstruction data remained in the transaction when freeing it, there were cases where it further subtracted the memory counter from zero, resulting in an assertion failure. This change calculates the memory size for each change and updates the memory usage to precisely the amount that has been freed. Backpatch to v17, where this was introducd. Reviewed-by: Amit Kapila, Shlok Kyal Discussion: https://postgr.es/m/CAD21AoAqkNUvicgKPT_dXzNoOwpPkVTg0QPPxEcWmzT0moCJ1g%40mail.gmail.com Backpatch-through: 17	1 year ago
Amit Kapila	6f4bdf8152	Fix assertion during streaming of multi-insert toast changes. ... While decoding the multi-insert WAL we can't clean the toast untill we get the last insert of that WAL record. Now if we stream the changes before we get the last change, the memory for toast chunks won't be released and we expect the txn to have streamed all changes after streaming. This restriction is mainly to ensure the correctness of streamed transactions and it doesn't seem worth uplifting such a restriction just to allow this case because anyway we will stream the transaction once such an insert is complete. Previously we were using two different flags (one for toast tuples and another for speculative inserts) to indicate partial changes. Now instead we replaced both of them with a single flag to indicate partial changes. Reported-by: Pavan Deolasee Author: Dilip Kumar Reviewed-by: Pavan Deolasee, Amit Kapila Discussion: https://postgr.es/m/CABOikdN-_858zojYN-2tNcHiVTw-nhxPwoQS4quExeweQfG1Ug@mail.gmail.com	5 years ago
Amit Kapila	82a0ba7707	Fix the logical streaming test. ... Commit 7259736a6e added the capability to stream changes in ReorderBuffer which has some tests to test the streaming mode. It is quite possible that while this test is running a parallel transaction could be logged by autovacuum. Such a transaction won't perform any insert/update/delete to non-catalog tables so will be shown as an empty transaction. Fix it by skipping the empty transactions during this test. Per report by buildfarm.	5 years ago
Amit Kapila	7259736a6e	Implement streaming mode in ReorderBuffer. ... Instead of serializing the transaction to disk after reaching the logical_decoding_work_mem limit in memory, we consume the changes we have in memory and invoke stream API methods added by commit 45fdc9738b. However, sometimes if we have incomplete toast or speculative insert we spill to the disk because we can't generate the complete tuple and stream. And, as soon as we get the complete tuple we stream the transaction including the serialized changes. We can do this incremental processing thanks to having assignments (associating subxact with toplevel xacts) in WAL right away, and thanks to logging the invalidation messages at each command end. These features are added by commits 0bead9af48 and c55040ccd0 respectively. Now that we can stream in-progress transactions, the concurrent aborts may cause failures when the output plugin consults catalogs (both system and user-defined). We handle such failures by returning ERRCODE_TRANSACTION_ROLLBACK sqlerrcode from system table scan APIs to the backend or WALSender decoding a specific uncommitted transaction. The decoding logic on the receipt of such a sqlerrcode aborts the decoding of the current transaction and continue with the decoding of other transactions. We have ReorderBufferTXN pointer in each ReorderBufferChange by which we know which xact it belongs to. The output plugin can use this to decide which changes to discard in case of stream_abort_cb (e.g. when a subxact gets discarded). We also provide a new option via SQL APIs to fetch the changes being streamed. Author: Dilip Kumar, Tomas Vondra, Amit Kapila, Nikhil Sontakke Reviewed-by: Amit Kapila, Kuntal Ghosh, Ajin Cherian Tested-by: Neha Sharma, Mahendra Singh Thalor and Ajin Cherian Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com	5 years ago