From 03c567bb534219acdd76b0acc40e544c76f938e5 Mon Sep 17 00:00:00 2001 From: John Naylor Date: Fri, 21 Jan 2022 17:41:58 -0500 Subject: [PATCH] do only critical work during single-user vacuum? Jan 21 John Naylor --- src/backend/commands/vacuum.c | 76 +++++++++++++++++++++++++++++++++-- src/include/commands/vacuum.h | 1 + 2 files changed, 74 insertions(+), 3 deletions(-) diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index d1dadc54e47..c7bc97d3f76 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -52,6 +52,7 @@ #include "storage/proc.h" #include "storage/procarray.h" #include "utils/acl.h" +#include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/guc.h" #include "utils/memutils.h" @@ -114,6 +115,7 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) bool full = false; bool disable_page_skipping = false; bool process_toast = true; + bool wraparound = false; ListCell *lc; /* index_cleanup and truncate values unspecified for now */ @@ -200,6 +202,8 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) params.nworkers = nworkers; } } + else if (strcmp(opt->defname, "wraparound") == 0) + wraparound = defGetBoolean(opt); else ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), @@ -246,17 +250,51 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) } } + if (wraparound) + { + /* exclude incompatible options */ + foreach(lc, vacstmt->options) + { + DefElem *opt = (DefElem *) lfirst(lc); + + // WIP is there a better way? + if (strcmp(opt->defname, "wraparound") != 0 && + strcmp(opt->defname, "verbose") != 0 && + defGetBoolean(opt)) + + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("option \"%s\" is incompatible with WRAPAROUND", opt->defname), + parser_errposition(pstate, opt->location))); + } + + /* skip unnecessary work, as in failsafe mode */ + params.index_cleanup = VACOPTVALUE_DISABLED; + params.truncate = VACOPTVALUE_DISABLED; + } + /* - * All freeze ages are zero if the FREEZE option is given; otherwise pass - * them as -1 which means to use the default values. + * Set freeze ages to zero where appropriate; otherwise pass + * them as -1 which means to use the configured values. */ if (params.options & VACOPT_FREEZE) { + /* All freeze ages are zero if the FREEZE option is given */ params.freeze_min_age = 0; params.freeze_table_age = 0; params.multixact_freeze_min_age = 0; params.multixact_freeze_table_age = 0; } + else if (params.options & VACOPT_MINIMAL) + { + /* it's unlikely any selected table will not be eligible for aggressive vacuum, but make sure */ + params.freeze_table_age = 0; + params.multixact_freeze_table_age = 0; + + // WIP: It might be worth trying to do less work here, or at least hard-coding the default values + params.freeze_min_age = -1; + params.multixact_freeze_min_age = -1; + } else { params.freeze_min_age = -1; @@ -894,6 +932,8 @@ get_all_vacuum_rels(int options) Relation pgclass; TableScanDesc scan; HeapTuple tuple; + int32 table_xid_age, + table_mxid_age; pgclass = table_open(RelationRelationId, AccessShareLock); @@ -909,12 +949,42 @@ get_all_vacuum_rels(int options) if (!vacuum_is_relation_owner(relid, classForm, options)) continue; + if (options & VACOPT_MINIMAL) + { + /* + * Only consider relations able to hold unfrozen XIDs (anything else + * should have InvalidTransactionId in relfrozenxid anyway). + */ + if (classForm->relkind != RELKIND_RELATION && + classForm->relkind != RELKIND_MATVIEW && + classForm->relkind != RELKIND_TOASTVALUE) + { + Assert(!TransactionIdIsValid(classForm->relfrozenxid)); + Assert(!MultiXactIdIsValid(classForm->relminmxid)); + continue; + } + + table_xid_age = DirectFunctionCall1(xid_age, classForm->relfrozenxid); + table_mxid_age = DirectFunctionCall1(mxid_age, classForm->relminmxid); + + /* Hard-code 1 billion for the thresholds to avoid making assumptions + * about the configuration. This leaves some headroom for when the user + * returns to normal mode while also minimizing work. + * WIP: consider passing these constants via the params struct + */ + // FIXME to speed up testing + // if ((table_xid_age < 1000 * 1000 * 1000) && + // (table_mxid_age < 1000 * 1000 * 1000)) + if ((table_xid_age < 1000 * 1000) && + (table_mxid_age < 1000 * 1000)) + continue; + } /* * We include partitioned tables here; depending on which operation is * to be performed, caller will decide whether to process or ignore * them. */ - if (classForm->relkind != RELKIND_RELATION && + else if (classForm->relkind != RELKIND_RELATION && classForm->relkind != RELKIND_MATVIEW && classForm->relkind != RELKIND_PARTITIONED_TABLE) continue; diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h index 5d0bdfa4279..3d8b8fbbb1a 100644 --- a/src/include/commands/vacuum.h +++ b/src/include/commands/vacuum.h @@ -188,6 +188,7 @@ typedef struct VacAttrStats #define VACOPT_SKIP_LOCKED 0x20 /* skip if cannot get lock */ #define VACOPT_PROCESS_TOAST 0x40 /* process the TOAST table, if any */ #define VACOPT_DISABLE_PAGE_SKIPPING 0x80 /* don't skip any pages */ +#define VACOPT_MINIMAL 0x100 /* do minimal freezing work to prevent or get out of shutdown */ /* * Values used by index_cleanup and truncate params. -- 2.17.1