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pg_resetxlog: add option to set oldest xid & use by pg_upgrade

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Add pg_resetxlog -u option to set the oldest xid in pg_control.
Previously -x set this value be -2 billion less than the -x value.
However, this causes the server to immediately scan all relation's
relfrozenxid so it can advance pg_control's oldest xid to be inside the
autovacuum_freeze_max_age range, which is inefficient and might disrupt
diagnostic recovery.  pg_upgrade will use this option to better create
the new cluster to match the old cluster.

Reported-by: Jason Harvey, Floris Van Nee

Discussion: https://postgr.es/m/20190615183759.GB239428@rfd.leadboat.com, 87da83168c644fd9aae38f546cc70295@opammb0562.comp.optiver.com

Author: Bertrand Drouvot

Backpatch-through: 9.6
This commit is contained in:
Bruce Momjian
2021-07-26 22:38:15 -04:00
parent 24ba1a87e4
commit 74cf7d46a9
5 changed files with 85 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
src/bin/pg_resetwal/pg_resetwal.c
View File

@ -64,6 +64,7 @@ static XLogSegNo newXlogSegNo; /* new XLOG segment # */
static bool guessed = false; /* T if we had to guess at any values */
static const char *progname;
static uint32 set_xid_epoch = (uint32) -1;
static TransactionId set_oldest_xid = 0;
static TransactionId set_xid = 0;
static TransactionId set_oldest_commit_ts_xid = 0;
static TransactionId set_newest_commit_ts_xid = 0;
@ -101,6 +102,7 @@ main(int argc, char *argv[])
{"dry-run", no_argument, NULL, 'n'},
{"next-oid", required_argument, NULL, 'o'},
{"multixact-offset", required_argument, NULL, 'O'},
{"oldest-transaction-id", required_argument, NULL, 'u'},
{"next-transaction-id", required_argument, NULL, 'x'},
{"wal-segsize", required_argument, NULL, 1},
{NULL, 0, NULL, 0}
@ -135,7 +137,7 @@ main(int argc, char *argv[])
}
while ((c = getopt_long(argc, argv, "c:D:e:fl:m:no:O:x:", long_options, NULL)) != -1)
while ((c = getopt_long(argc, argv, "c:D:e:fl:m:no:O:u:x:", long_options, NULL)) != -1)
{
switch (c)
{
@ -168,6 +170,21 @@ main(int argc, char *argv[])
}
break;
case 'u':
set_oldest_xid = strtoul(optarg, &endptr, 0);
if (endptr == optarg || *endptr != '\0')
{
pg_log_error("invalid argument for option %s", "-u");
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
}
if (!TransactionIdIsNormal(set_oldest_xid))
{
pg_log_error("oldest transaction ID (-u) must be greater or equal to %u", FirstNormalTransactionId);
exit(1);
}
break;
case 'x':
set_xid = strtoul(optarg, &endptr, 0);
if (endptr == optarg || *endptr != '\0')
@ -176,9 +193,9 @@ main(int argc, char *argv[])
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
}
if (set_xid == 0)
if (!TransactionIdIsNormal(set_xid))
{
pg_log_error("transaction ID (-x) must not be 0");
pg_log_error("transaction ID (-x) must be greater or equal to %u", FirstNormalTransactionId);
exit(1);
}
break;
@ -428,25 +445,17 @@ main(int argc, char *argv[])
FullTransactionIdFromEpochAndXid(set_xid_epoch,
XidFromFullTransactionId(ControlFile.checkPointCopy.nextXid));
if (set_xid != 0)
if (set_oldest_xid != 0)
{
ControlFile.checkPointCopy.oldestXid = set_oldest_xid;
ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
}
if (set_xid != 0)
ControlFile.checkPointCopy.nextXid =
FullTransactionIdFromEpochAndXid(EpochFromFullTransactionId(ControlFile.checkPointCopy.nextXid),
set_xid);
/*
* For the moment, just set oldestXid to a value that will force
* immediate autovacuum-for-wraparound. It's not clear whether adding
* user control of this is useful, so let's just do something that's
* reasonably safe. The magic constant here corresponds to the
* maximum allowed value of autovacuum_freeze_max_age.
*/
ControlFile.checkPointCopy.oldestXid = set_xid - 2000000000;
if (ControlFile.checkPointCopy.oldestXid < FirstNormalTransactionId)
ControlFile.checkPointCopy.oldestXid += FirstNormalTransactionId;
ControlFile.checkPointCopy.oldestXidDB = InvalidOid;
}
if (set_oldest_commit_ts_xid != 0)
ControlFile.checkPointCopy.oldestCommitTsXid = set_oldest_commit_ts_xid;
if (set_newest_commit_ts_xid != 0)
@ -1209,20 +1218,21 @@ usage(void)
printf(_("Usage:\n %s [OPTION]... DATADIR\n\n"), progname);
printf(_("Options:\n"));
printf(_(" -c, --commit-timestamp-ids=XID,XID\n"
" set oldest and newest transactions bearing\n"
" commit timestamp (zero means no change)\n"));
printf(_(" [-D, --pgdata=]DATADIR data directory\n"));
printf(_(" -e, --epoch=XIDEPOCH set next transaction ID epoch\n"));
printf(_(" -f, --force force update to be done\n"));
printf(_(" -l, --next-wal-file=WALFILE set minimum starting location for new WAL\n"));
printf(_(" -m, --multixact-ids=MXID,MXID set next and oldest multitransaction ID\n"));
printf(_(" -n, --dry-run no update, just show what would be done\n"));
printf(_(" -o, --next-oid=OID set next OID\n"));
printf(_(" -O, --multixact-offset=OFFSET set next multitransaction offset\n"));
printf(_(" -V, --version output version information, then exit\n"));
printf(_(" -x, --next-transaction-id=XID set next transaction ID\n"));
printf(_(" --wal-segsize=SIZE size of WAL segments, in megabytes\n"));
printf(_(" -?, --help show this help, then exit\n"));
" set oldest and newest transactions bearing\n"
" commit timestamp (zero means no change)\n"));
printf(_(" [-D, --pgdata=]DATADIR data directory\n"));
printf(_(" -e, --epoch=XIDEPOCH set next transaction ID epoch\n"));
printf(_(" -f, --force force update to be done\n"));
printf(_(" -l, --next-wal-file=WALFILE set minimum starting location for new WAL\n"));
printf(_(" -m, --multixact-ids=MXID,MXID set next and oldest multitransaction ID\n"));
printf(_(" -n, --dry-run no update, just show what would be done\n"));
printf(_(" -o, --next-oid=OID set next OID\n"));
printf(_(" -O, --multixact-offset=OFFSET set next multitransaction offset\n"));
printf(_(" -u, --oldest-transaction-id=XID set oldest transaction ID\n"));
printf(_(" -V, --version output version information, then exit\n"));
printf(_(" -x, --next-transaction-id=XID set next transaction ID\n"));
printf(_(" --wal-segsize=SIZE size of WAL segments, in megabytes\n"));
printf(_(" -?, --help show this help, then exit\n"));
printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
}

17
src/bin/pg_upgrade/controldata.c
View File

@ -44,6 +44,7 @@ get_control_data(ClusterInfo *cluster, bool live_check)
bool got_oid = false;
bool got_multi = false;
bool got_oldestmulti = false;
bool got_oldestxid = false;
bool got_mxoff = false;
bool got_nextxlogfile = false;
bool got_float8_pass_by_value = false;
@ -312,6 +313,17 @@ get_control_data(ClusterInfo *cluster, bool live_check)
cluster->controldata.chkpnt_nxtmulti = str2uint(p);
got_multi = true;
}
else if ((p = strstr(bufin, "Latest checkpoint's oldestXID:")) != NULL)
{
p = strchr(p, ':');
if (p == NULL || strlen(p) <= 1)
pg_fatal("%d: controldata retrieval problem\n", __LINE__);
p++; /* remove ':' char */
cluster->controldata.chkpnt_oldstxid = str2uint(p);
got_oldestxid = true;
}
else if ((p = strstr(bufin, "Latest checkpoint's oldestMultiXid:")) != NULL)
{
p = strchr(p, ':');
@ -544,7 +556,7 @@ get_control_data(ClusterInfo *cluster, bool live_check)
/* verify that we got all the mandatory pg_control data */
if (!got_xid || !got_oid ||
!got_multi ||
!got_multi || !got_oldestxid ||
(!got_oldestmulti &&
cluster->controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER) ||
!got_mxoff || (!live_check && !got_nextxlogfile) ||
@ -575,6 +587,9 @@ get_control_data(ClusterInfo *cluster, bool live_check)
cluster->controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER)
pg_log(PG_REPORT, " latest checkpoint oldest MultiXactId\n");
if (!got_oldestxid)
pg_log(PG_REPORT, " latest checkpoint oldestXID\n");
if (!got_mxoff)
pg_log(PG_REPORT, " latest checkpoint next MultiXactOffset\n");

7
src/bin/pg_upgrade/pg_upgrade.c
View File

@ -467,6 +467,13 @@ copy_xact_xlog_xid(void)
GET_MAJOR_VERSION(new_cluster.major_version) <= 906 ?
"pg_clog" : "pg_xact");
prep_status("Setting oldest XID for new cluster");
exec_prog(UTILITY_LOG_FILE, NULL, true, true,
"\"%s/pg_resetwal\" -f -u %u \"%s\"",
new_cluster.bindir, old_cluster.controldata.chkpnt_oldstxid,
new_cluster.pgdata);
check_ok();
/* set the next transaction id and epoch of the new cluster */
prep_status("Setting next transaction ID and epoch for new cluster");
exec_prog(UTILITY_LOG_FILE, NULL, true, true,

1
src/bin/pg_upgrade/pg_upgrade.h
View File

@ -207,6 +207,7 @@ typedef struct
uint32 chkpnt_nxtmulti;
uint32 chkpnt_nxtmxoff;
uint32 chkpnt_oldstMulti;
uint32 chkpnt_oldstxid;
uint32 align;
uint32 blocksz;
uint32 largesz;