diff options
| author | Magnus Hagander <magnus@hagander.net> | 2018-04-05 21:57:26 +0200 |
|---|---|---|
| committer | Magnus Hagander <magnus@hagander.net> | 2018-04-05 22:04:48 +0200 |
| commit | 1fde38beaa0c3e66c340efc7cc0dc272d6254bb0 (patch) | |
| tree | 1e8291cd8523789d919e239e92aa3ecd6aa749de /src/backend/storage | |
| parent | c39e903d510064e4415bbadb43e34f6998351cca (diff) | |
| download | postgresql-1fde38beaa0c3e66c340efc7cc0dc272d6254bb0.tar.gz postgresql-1fde38beaa0c3e66c340efc7cc0dc272d6254bb0.zip | |
Allow on-line enabling and disabling of data checksums
This makes it possible to turn checksums on in a live cluster, without
the previous need for dump/reload or logical replication (and to turn it
off).
Enabling checkusm starts a background process in the form of a
launcher/worker combination that goes through the entire database and
recalculates checksums on each and every page. Only when all pages have
been checksummed are they fully enabled in the cluster. Any failure of
the process will revert to checksums off and the process has to be
started.
This adds a new WAL record that indicates the state of checksums, so
the process works across replicated clusters.
Authors: Magnus Hagander and Daniel Gustafsson
Review: Tomas Vondra, Michael Banck, Heikki Linnakangas, Andrey Borodin
Diffstat (limited to 'src/backend/storage')
| -rw-r--r-- | src/backend/storage/ipc/ipci.c | 2 | ||||
| -rw-r--r-- | src/backend/storage/page/README | 3 | ||||
| -rw-r--r-- | src/backend/storage/page/bufpage.c | 6 |
3 files changed, 7 insertions, 4 deletions
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c index 0c86a581c03..853e1e472f6 100644 --- a/src/backend/storage/ipc/ipci.c +++ b/src/backend/storage/ipc/ipci.c @@ -27,6 +27,7 @@ #include "postmaster/autovacuum.h" #include "postmaster/bgworker_internals.h" #include "postmaster/bgwriter.h" +#include "postmaster/checksumhelper.h" #include "postmaster/postmaster.h" #include "replication/logicallauncher.h" #include "replication/slot.h" @@ -261,6 +262,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port) WalSndShmemInit(); WalRcvShmemInit(); ApplyLauncherShmemInit(); + ChecksumHelperShmemInit(); /* * Set up other modules that need some shared memory space diff --git a/src/backend/storage/page/README b/src/backend/storage/page/README index 5127d98da37..f873fb0eea1 100644 --- a/src/backend/storage/page/README +++ b/src/backend/storage/page/README @@ -9,7 +9,8 @@ have a very low measured incidence according to research on large server farms, http://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf, discussed 2010/12/22 on -hackers list. -Current implementation requires this be enabled system-wide at initdb time. +Checksums can be enabled at initdb time, but can also be turned on and off +using pg_enable_data_checksums()/pg_disable_data_checksums() at runtime. The checksum is not valid at all times on a data page!! The checksum is valid when the page leaves the shared pool and is checked diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c index dfbda5458fd..790e4b860ad 100644 --- a/src/backend/storage/page/bufpage.c +++ b/src/backend/storage/page/bufpage.c @@ -93,7 +93,7 @@ PageIsVerified(Page page, BlockNumber blkno) */ if (!PageIsNew(page)) { - if (DataChecksumsEnabled()) + if (DataChecksumsNeedVerify()) { checksum = pg_checksum_page((char *) page, blkno); @@ -1168,7 +1168,7 @@ PageSetChecksumCopy(Page page, BlockNumber blkno) static char *pageCopy = NULL; /* If we don't need a checksum, just return the passed-in data */ - if (PageIsNew(page) || !DataChecksumsEnabled()) + if (PageIsNew(page) || !DataChecksumsNeedWrite()) return (char *) page; /* @@ -1195,7 +1195,7 @@ void PageSetChecksumInplace(Page page, BlockNumber blkno) { /* If we don't need a checksum, just return */ - if (PageIsNew(page) || !DataChecksumsEnabled()) + if (PageIsNew(page) || !DataChecksumsNeedWrite()) return; ((PageHeader) page)->pd_checksum = pg_checksum_page((char *) page, blkno); |