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Fix leaking of small spilled subtransactions during logical decoding.

When, during logical decoding, a transaction gets too big, it's
contents get spilled to disk. Not just the top-transaction gets
spilled, but *also* all of its subtransactions, even if they're not
that large themselves.  Unfortunately we didn't clean up
such small spilled subtransactions from disk.

Fix that, by keeping better track of whether a transaction has been
spilled to disk.

Author: Andres Freund
Reported-By: Dmitriy Sarafannikov, Fabrízio de Royes Mello
Discussion:
    https://postgr.es/m/1457621358.355011041@f382.i.mail.ru
    https://postgr.es/m/CAFcNs+qNMhNYii4nxpO6gqsndiyxNDYV0S=JNq0v_sEE+9PHXg@mail.gmail.com
Backpatch: 9.4-, where logical decoding was introduced
This commit is contained in:
Andres Freund
2017-06-18 18:48:22 -07:00
parent b4166a8df9
commit 3bdea167eb
2 changed files with 13 additions and 3 deletions

View File

@@ -212,6 +212,15 @@ typedef struct ReorderBufferTXN
*/
uint64 nentries_mem;
/*
* Has this transaction been spilled to disk? It's not always possible to
* deduce that fact by comparing nentries with nentries_mem, because
* e.g. subtransactions of a large transaction might get serialized
* together with the parent - if they're restored to memory they'd have
* nentries_mem == nentries.
*/
bool serialized;
/*
* List of ReorderBufferChange structs, including new Snapshots and new
* CommandIds