From 6bd7816e766abd6c10db16ed0af93a512b1a662d Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Tue, 14 Mar 2017 11:51:11 -0400 Subject: [PATCH] Fix failure to mark init buffers as BM_PERMANENT. This could result in corruption of the init fork of an unlogged index if the ambuildempty routine for that index used shared buffers to create the init fork, which was true for gin, gist, and hash indexes. Patch by me, based on an earlier patch by Michael Paquier, who also reviewed this one. This also incorporates an idea from Artur Zakirov. Discussion: http://postgr.es/m/CACYUyc8yccE4xfxhqxfh_Mh38j7dRFuxfaK1p6dSNAEUakxUyQ@mail.gmail.com --- src/backend/storage/buffer/bufmgr.c | 7 ++++++- src/include/storage/buf_internals.h | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 16d4f2839aa..a70e26896c7 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -870,10 +870,15 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum, * paranoia. We also reset the usage_count since any recency of use of * the old content is no longer relevant. (The usage_count starts out at * 1 so that the buffer can survive one clock-sweep pass.) + * + * Make sure BM_PERMANENT is set for buffers that must be written at every + * checkpoint. Unlogged buffers only need to be written at shutdown + * checkpoints, except for their "init" forks, which need to be treated + * just like permanent relations. */ buf->tag = newTag; buf->flags &= ~(BM_VALID | BM_DIRTY | BM_JUST_DIRTIED | BM_CHECKPOINT_NEEDED | BM_IO_ERROR | BM_PERMANENT); - if (relpersistence == RELPERSISTENCE_PERMANENT) + if (relpersistence == RELPERSISTENCE_PERMANENT || forkNum == INIT_FORKNUM) buf->flags |= BM_TAG_VALID | BM_PERMANENT; else buf->flags |= BM_TAG_VALID; diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index 870bb9cea19..e9520ef3b2e 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -39,7 +39,7 @@ #define BM_PIN_COUNT_WAITER (1 << 6) /* have waiter for sole pin */ #define BM_CHECKPOINT_NEEDED (1 << 7) /* must write for checkpoint */ #define BM_PERMANENT (1 << 8) /* permanent relation (not - * unlogged) */ + * unlogged, or init fork) */ typedef bits16 BufFlags;