From: Robert Haas Date: Tue, 14 Mar 2017 15:51:11 +0000 (-0400) Subject: Fix failure to mark init buffers as BM_PERMANENT. X-Git-Tag: REL_10_BETA1~654 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=87f99820349bbb020d1d65dd739a910c6f9c813b;p=postgresql 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 brin, 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 --- diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 3cb51204dc..2ca2ab9753 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -1292,12 +1292,17 @@ 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_state &= ~(BM_VALID | BM_DIRTY | BM_JUST_DIRTIED | BM_CHECKPOINT_NEEDED | BM_IO_ERROR | BM_PERMANENT | BUF_USAGECOUNT_MASK); - if (relpersistence == RELPERSISTENCE_PERMANENT) + if (relpersistence == RELPERSISTENCE_PERMANENT || forkNum == INIT_FORKNUM) buf_state |= BM_TAG_VALID | BM_PERMANENT | BUF_USAGECOUNT_ONE; else buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE; diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index d117b66537..ff99f6b5e2 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -64,8 +64,8 @@ #define BM_JUST_DIRTIED (1U << 28) /* dirtied since write started */ #define BM_PIN_COUNT_WAITER (1U << 29) /* have waiter for sole pin */ #define BM_CHECKPOINT_NEEDED (1U << 30) /* must write for checkpoint */ -#define BM_PERMANENT (1U << 31) /* permanent relation (not - * unlogged) */ +#define BM_PERMANENT (1U << 31) /* permanent buffer (not + * unlogged, or init fork) */ /* * The maximum allowed value of usage_count represents a tradeoff between * accuracy and speed of the clock-sweep buffer management algorithm. A