From 0a5e708e2bd87adb0779d7c8758e5743cc1c0adf Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Mon, 26 Jul 2021 22:38:14 -0400 Subject: [PATCH] pg_resetxlog: add option to set oldest xid & use by pg_upgrade 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 --- doc/src/sgml/ref/pg_resetwal.sgml | 20 +++++++++ src/bin/pg_resetwal/pg_resetwal.c | 72 ++++++++++++++++++------------- src/bin/pg_upgrade/controldata.c | 17 +++++++- src/bin/pg_upgrade/pg_upgrade.c | 7 +++ src/bin/pg_upgrade/pg_upgrade.h | 1 + 5 files changed, 85 insertions(+), 32 deletions(-) diff --git a/doc/src/sgml/ref/pg_resetwal.sgml b/doc/src/sgml/ref/pg_resetwal.sgml index b3b750e722..3e4882cdc6 100644 --- a/doc/src/sgml/ref/pg_resetwal.sgml +++ b/doc/src/sgml/ref/pg_resetwal.sgml @@ -297,6 +297,26 @@ PostgreSQL documentation + + + + + + Manually set the oldest unfrozen transaction ID. + + + + A safe value can be determined by looking for the numerically smallest + file name in the directory pg_xact under the data directory + and then multiplying by 1048576 (0x100000). Note that the file names are in + hexadecimal. It is usually easiest to specify the option value in + hexadecimal too. For example, if 0007 is the smallest entry + in pg_xact, -u 0x700000 will work (five + trailing zeroes provide the proper multiplier). + + + + diff --git a/src/bin/pg_resetwal/pg_resetwal.c b/src/bin/pg_resetwal/pg_resetwal.c index 233441837f..ec35dbec0b 100644 --- a/src/bin/pg_resetwal/pg_resetwal.c +++ b/src/bin/pg_resetwal/pg_resetwal.c @@ -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.nextFullXid)); - 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.nextFullXid = FullTransactionIdFromEpochAndXid(EpochFromFullTransactionId(ControlFile.checkPointCopy.nextFullXid), 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); } diff --git a/src/bin/pg_upgrade/controldata.c b/src/bin/pg_upgrade/controldata.c index 39bcaa8fe1..26459b4190 100644 --- a/src/bin/pg_upgrade/controldata.c +++ b/src/bin/pg_upgrade/controldata.c @@ -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, ':'); @@ -530,7 +542,7 @@ 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) || @@ -561,6 +573,9 @@ 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"); diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c index 1bc86e4205..a34f9c7a77 100644 --- a/src/bin/pg_upgrade/pg_upgrade.c +++ b/src/bin/pg_upgrade/pg_upgrade.c @@ -471,6 +471,13 @@ 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, diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h index dbdf4d4a55..f08b90bfbd 100644 --- a/src/bin/pg_upgrade/pg_upgrade.h +++ b/src/bin/pg_upgrade/pg_upgrade.h @@ -207,6 +207,7 @@ typedef struct uint32 chkpnt_nxtmulti; uint32 chkpnt_nxtmxoff; uint32 chkpnt_oldstMulti; + uint32 chkpnt_oldstxid; uint32 align; uint32 blocksz; uint32 largesz;