From 9548bb49865db3a04bbdda4c63df611142e22964 Mon Sep 17 00:00:00 2001 From: Jeff Davis Date: Tue, 26 Sep 2023 12:10:11 -0700 Subject: [PATCH v2] Fix GenericXLogFinish(). Mark the buffers dirty before writing WAL. Discussion: https://postgr.es/m/25104133-7df8-cae3-b9a2-1c0aaa1c094a@iki.fi --- src/backend/access/transam/generic_xlog.c | 53 ++++++++++------------- 1 file changed, 23 insertions(+), 30 deletions(-) diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c index 6c68191ca6..2d5ff4aa7c 100644 --- a/src/backend/access/transam/generic_xlog.c +++ b/src/backend/access/transam/generic_xlog.c @@ -347,6 +347,10 @@ GenericXLogFinish(GenericXLogState *state) START_CRIT_SECTION(); + /* + * Compute deltas if necessary, write changes to buffers, mark + * buffers dirty, and register changes. + */ for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++) { PageData *pageData = &state->pages[i]; @@ -359,41 +363,31 @@ GenericXLogFinish(GenericXLogState *state) page = BufferGetPage(pageData->buffer); pageHeader = (PageHeader) pageData->image; + /* delta not needed for a full page image */ + if (!(pageData->flags & GENERIC_XLOG_FULL_IMAGE)) + computeDelta(pageData, page, (Page) pageData->image); + + /* + * Apply the image, being careful to zero the "hole" between + * pd_lower and pd_upper in order to avoid divergence between + * actual page state and what replay would produce. + */ + memcpy(page, pageData->image, pageHeader->pd_lower); + memset(page + pageHeader->pd_lower, 0, + pageHeader->pd_upper - pageHeader->pd_lower); + memcpy(page + pageHeader->pd_upper, + pageData->image + pageHeader->pd_upper, + BLCKSZ - pageHeader->pd_upper); + + MarkBufferDirty(pageData->buffer); + if (pageData->flags & GENERIC_XLOG_FULL_IMAGE) { - /* - * A full-page image does not require us to supply any xlog - * data. Just apply the image, being careful to zero the - * "hole" between pd_lower and pd_upper in order to avoid - * divergence between actual page state and what replay would - * produce. - */ - memcpy(page, pageData->image, pageHeader->pd_lower); - memset(page + pageHeader->pd_lower, 0, - pageHeader->pd_upper - pageHeader->pd_lower); - memcpy(page + pageHeader->pd_upper, - pageData->image + pageHeader->pd_upper, - BLCKSZ - pageHeader->pd_upper); - XLogRegisterBuffer(i, pageData->buffer, REGBUF_FORCE_IMAGE | REGBUF_STANDARD); } else { - /* - * In normal mode, calculate delta and write it as xlog data - * associated with this page. - */ - computeDelta(pageData, page, (Page) pageData->image); - - /* Apply the image, with zeroed "hole" as above */ - memcpy(page, pageData->image, pageHeader->pd_lower); - memset(page + pageHeader->pd_lower, 0, - pageHeader->pd_upper - pageHeader->pd_lower); - memcpy(page + pageHeader->pd_upper, - pageData->image + pageHeader->pd_upper, - BLCKSZ - pageHeader->pd_upper); - XLogRegisterBuffer(i, pageData->buffer, REGBUF_STANDARD); XLogRegisterBufData(i, pageData->delta, pageData->deltaLen); } @@ -402,7 +396,7 @@ GenericXLogFinish(GenericXLogState *state) /* Insert xlog record */ lsn = XLogInsert(RM_GENERIC_ID, 0); - /* Set LSN and mark buffers dirty */ + /* Set LSN */ for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++) { PageData *pageData = &state->pages[i]; @@ -410,7 +404,6 @@ GenericXLogFinish(GenericXLogState *state) if (BufferIsInvalid(pageData->buffer)) continue; PageSetLSN(BufferGetPage(pageData->buffer), lsn); - MarkBufferDirty(pageData->buffer); } END_CRIT_SECTION(); } -- 2.34.1