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| author | Teodor Sigaev <teodor@sigaev.ru> | 2017-03-20 18:48:46 +0300 |
|---|---|---|
| committer | Teodor Sigaev <teodor@sigaev.ru> | 2017-03-20 18:48:46 +0300 |
| commit | 9cf6033281fdaf938b826545a643f951086d8671 (patch) | |
| tree | 9c71cbb0b7fccfaa914ab84221bd5ba0c51b9c91 /src/backend/storage/buffer/bufmgr.c | |
| parent | de34123834c3fa465b97f65ded171888edbfbccf (diff) | |
| download | postgresql-9cf6033281fdaf938b826545a643f951086d8671.tar.gz postgresql-9cf6033281fdaf938b826545a643f951086d8671.zip | |
Revert unintentional change in increasing usage count during pin of buffers,
this makes buffer access strategy have no effect.
Change was a part of commit 48354581a49c30f5757c203415aa8412d85b0f70 during 9.6
release cycle, so backpath to 9.6
Reported-by: Jim Nasby
Author: Alexander Korotkov
Reviewed-by: Jim Nasby, Andres Freund
https://commitfest.postgresql.org/13/1029/
Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 2ca2ab9753c..2109cbf8587 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -1595,9 +1595,21 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy) /* increase refcount */ buf_state += BUF_REFCOUNT_ONE; - /* increase usagecount unless already max */ - if (BUF_STATE_GET_USAGECOUNT(buf_state) != BM_MAX_USAGE_COUNT) - buf_state += BUF_USAGECOUNT_ONE; + if (strategy == NULL) + { + /* Default case: increase usagecount unless already max. */ + if (BUF_STATE_GET_USAGECOUNT(buf_state) < BM_MAX_USAGE_COUNT) + buf_state += BUF_USAGECOUNT_ONE; + } + else + { + /* + * Ring buffers shouldn't evict others from pool. Thus we + * don't make usagecount more than 1. + */ + if (BUF_STATE_GET_USAGECOUNT(buf_state) == 0) + buf_state += BUF_USAGECOUNT_ONE; + } if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state, buf_state)) |