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pg_prewarm: Add automatic prewarm feature.
Periodically while the server is running, and at shutdown, write out a list of blocks in shared buffers. When the server reaches consistency -- unfortunatey, we can't do it before that point without breaking things -- reload those blocks into any still-unused shared buffers. Mithun Cy and Robert Haas, reviewed and tested by Beena Emerson, Amit Kapila, Jim Nasby, and Rafia Sabih. Discussion: http://postgr.es/m/CAD__OugubOs1Vy7kgF6xTjmEqTR4CrGAv8w+ZbaY_+MZeitukw@mail.gmail.com
This commit is contained in:
Robert Haas
parent
66ed3829df
commit
79ccd7cbd5
2
contrib/file_fdw/data/list1.csv
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2
contrib/file_fdw/data/list1.csv
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1,foo
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1,bar
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2
contrib/file_fdw/data/list2.bad
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contrib/file_fdw/data/list2.bad
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2,baz
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1,qux
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contrib/file_fdw/data/list2.csv
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contrib/file_fdw/data/list2.csv
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2,baz
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2,qux
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@ -1,10 +1,10 @@
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# contrib/pg_prewarm/Makefile
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# contrib/pg_prewarm/Makefile
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MODULE_big = pg_prewarm
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MODULE_big = pg_prewarm
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OBJS = pg_prewarm.o $(WIN32RES)
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OBJS = pg_prewarm.o autoprewarm.o $(WIN32RES)
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EXTENSION = pg_prewarm
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EXTENSION = pg_prewarm
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DATA = pg_prewarm--1.1.sql pg_prewarm--1.0--1.1.sql
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DATA = pg_prewarm--1.1--1.2.sql pg_prewarm--1.1.sql pg_prewarm--1.0--1.1.sql
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PGFILEDESC = "pg_prewarm - preload relation data into system buffer cache"
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PGFILEDESC = "pg_prewarm - preload relation data into system buffer cache"
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ifdef USE_PGXS
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ifdef USE_PGXS
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924
contrib/pg_prewarm/autoprewarm.c
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924
contrib/pg_prewarm/autoprewarm.c
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/*-------------------------------------------------------------------------
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*
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* autoprewarm.c
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* Periodically dump information about the blocks present in
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* shared_buffers, and reload them on server restart.
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*
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* Due to locking considerations, we can't actually begin prewarming
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* until the server reaches a consistent state. We need the catalogs
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* to be consistent so that we can figure out which relation to lock,
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* and we need to lock the relations so that we don't try to prewarm
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* pages from a relation that is in the process of being dropped.
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*
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* While prewarming, autoprewarm will use two workers. There's a
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* master worker that reads and sorts the list of blocks to be
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* prewarmed and then launches a per-database worker for each
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* relevant database in turn. The former keeps running after the
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* initial prewarm is complete to update the dump file periodically.
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*
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* Copyright (c) 2016-2017, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/pg_prewarm/autoprewarm.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <unistd.h>
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#include "access/heapam.h"
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#include "access/xact.h"
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#include "catalog/pg_class.h"
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#include "catalog/pg_type.h"
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "postmaster/bgworker.h"
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#include "storage/buf_internals.h"
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#include "storage/dsm.h"
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#include "storage/ipc.h"
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#include "storage/latch.h"
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#include "storage/lwlock.h"
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#include "storage/proc.h"
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#include "storage/procsignal.h"
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#include "storage/shmem.h"
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#include "storage/smgr.h"
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#include "tcop/tcopprot.h"
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#include "utils/acl.h"
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#include "utils/guc.h"
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#include "utils/memutils.h"
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#include "utils/rel.h"
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#include "utils/relfilenodemap.h"
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#include "utils/resowner.h"
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#define AUTOPREWARM_FILE "autoprewarm.blocks"
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/* Metadata for each block we dump. */
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typedef struct BlockInfoRecord
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{
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Oid database;
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Oid tablespace;
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Oid filenode;
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ForkNumber forknum;
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BlockNumber blocknum;
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} BlockInfoRecord;
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/* Shared state information for autoprewarm bgworker. */
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typedef struct AutoPrewarmSharedState
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{
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LWLock lock; /* mutual exclusion */
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pid_t bgworker_pid; /* for main bgworker */
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pid_t pid_using_dumpfile; /* for autoprewarm or block dump */
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/* Following items are for communication with per-database worker */
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dsm_handle block_info_handle;
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Oid database;
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int64 prewarm_start_idx;
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int64 prewarm_stop_idx;
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int64 prewarmed_blocks;
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} AutoPrewarmSharedState;
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void _PG_init(void);
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void autoprewarm_main(Datum main_arg);
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void autoprewarm_database_main(Datum main_arg);
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PG_FUNCTION_INFO_V1(autoprewarm_start_worker);
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PG_FUNCTION_INFO_V1(autoprewarm_dump_now);
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static void apw_load_buffers(void);
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static int64 apw_dump_now(bool is_bgworker, bool dump_unlogged);
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static void apw_start_master_worker(void);
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static void apw_start_database_worker(void);
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static bool apw_init_shmem(void);
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static void apw_detach_shmem(int code, Datum arg);
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static int apw_compare_blockinfo(const void *p, const void *q);
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static void apw_sigterm_handler(SIGNAL_ARGS);
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static void apw_sighup_handler(SIGNAL_ARGS);
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/* Flags set by signal handlers */
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static volatile sig_atomic_t got_sigterm = false;
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static volatile sig_atomic_t got_sighup = false;
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/* Pointer to shared-memory state. */
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static AutoPrewarmSharedState *apw_state = NULL;
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/* GUC variables. */
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static bool autoprewarm = true; /* start worker? */
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static int autoprewarm_interval; /* dump interval */
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/*
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* Module load callback.
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*/
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void
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_PG_init(void)
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{
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DefineCustomIntVariable("pg_prewarm.autoprewarm_interval",
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"Sets the interval between dumps of shared buffers",
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"If set to zero, time-based dumping is disabled.",
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&autoprewarm_interval,
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300,
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0, INT_MAX / 1000,
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PGC_SIGHUP,
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GUC_UNIT_S,
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NULL,
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NULL,
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NULL);
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if (!process_shared_preload_libraries_in_progress)
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return;
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/* can't define PGC_POSTMASTER variable after startup */
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DefineCustomBoolVariable("pg_prewarm.autoprewarm",
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"Starts the autoprewarm worker.",
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NULL,
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&autoprewarm,
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true,
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PGC_POSTMASTER,
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0,
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NULL,
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NULL,
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NULL);
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EmitWarningsOnPlaceholders("pg_prewarm");
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RequestAddinShmemSpace(MAXALIGN(sizeof(AutoPrewarmSharedState)));
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/* Register autoprewarm worker, if enabled. */
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if (autoprewarm)
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apw_start_master_worker();
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}
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/*
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* Main entry point for the master autoprewarm process. Per-database workers
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* have a separate entry point.
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*/
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void
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autoprewarm_main(Datum main_arg)
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{
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bool first_time = true;
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TimestampTz last_dump_time = 0;
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/* Establish signal handlers; once that's done, unblock signals. */
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pqsignal(SIGTERM, apw_sigterm_handler);
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pqsignal(SIGHUP, apw_sighup_handler);
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pqsignal(SIGUSR1, procsignal_sigusr1_handler);
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BackgroundWorkerUnblockSignals();
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/* Create (if necessary) and attach to our shared memory area. */
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if (apw_init_shmem())
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first_time = false;
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/* Set on-detach hook so that our PID will be cleared on exit. */
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on_shmem_exit(apw_detach_shmem, 0);
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/*
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* Store our PID in the shared memory area --- unless there's already
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* another worker running, in which case just exit.
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*/
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LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
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if (apw_state->bgworker_pid != InvalidPid)
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{
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LWLockRelease(&apw_state->lock);
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ereport(LOG,
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(errmsg("autoprewarm worker is already running under PID %d",
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apw_state->bgworker_pid)));
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return;
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}
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apw_state->bgworker_pid = MyProcPid;
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LWLockRelease(&apw_state->lock);
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/*
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* Preload buffers from the dump file only if we just created the shared
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* memory region. Otherwise, it's either already been done or shouldn't
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* be done - e.g. because the old dump file has been overwritten since the
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* server was started.
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*
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* There's not much point in performing a dump immediately after we finish
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* preloading; so, if we do end up preloading, consider the last dump time
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* to be equal to the current time.
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*/
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if (first_time)
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{
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apw_load_buffers();
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last_dump_time = GetCurrentTimestamp();
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}
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/* Periodically dump buffers until terminated. */
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while (!got_sigterm)
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{
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int rc;
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/* In case of a SIGHUP, just reload the configuration. */
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if (got_sighup)
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{
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got_sighup = false;
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ProcessConfigFile(PGC_SIGHUP);
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}
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if (autoprewarm_interval <= 0)
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{
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/* We're only dumping at shutdown, so just wait forever. */
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rc = WaitLatch(&MyProc->procLatch,
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WL_LATCH_SET | WL_POSTMASTER_DEATH,
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-1L,
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PG_WAIT_EXTENSION);
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}
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else
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{
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long delay_in_ms = 0;
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TimestampTz next_dump_time = 0;
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long secs = 0;
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int usecs = 0;
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/* Compute the next dump time. */
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next_dump_time =
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TimestampTzPlusMilliseconds(last_dump_time,
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autoprewarm_interval * 1000);
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TimestampDifference(GetCurrentTimestamp(), next_dump_time,
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&secs, &usecs);
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delay_in_ms = secs + (usecs / 1000);
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/* Perform a dump if it's time. */
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if (delay_in_ms <= 0)
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{
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last_dump_time = GetCurrentTimestamp();
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apw_dump_now(true, false);
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continue;
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}
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/* Sleep until the next dump time. */
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rc = WaitLatch(&MyProc->procLatch,
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WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
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delay_in_ms,
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PG_WAIT_EXTENSION);
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}
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/* Reset the latch, bail out if postmaster died, otherwise loop. */
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ResetLatch(&MyProc->procLatch);
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if (rc & WL_POSTMASTER_DEATH)
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proc_exit(1);
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}
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/*
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* Dump one last time. We assume this is probably the result of a system
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* shutdown, although it's possible that we've merely been terminated.
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*/
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apw_dump_now(true, true);
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}
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/*
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* Read the dump file and launch per-database workers one at a time to
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* prewarm the buffers found there.
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*/
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static void
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apw_load_buffers(void)
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{
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FILE *file = NULL;
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int64 num_elements,
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i;
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BlockInfoRecord *blkinfo;
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dsm_segment *seg;
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/*
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* Skip the prewarm if the dump file is in use; otherwise, prevent any
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* other process from writing it while we're using it.
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*/
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LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
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if (apw_state->pid_using_dumpfile == InvalidPid)
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apw_state->pid_using_dumpfile = MyProcPid;
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else
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{
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LWLockRelease(&apw_state->lock);
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ereport(LOG,
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(errmsg("skipping prewarm because block dump file is being written by PID %d",
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apw_state->pid_using_dumpfile)));
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return;
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}
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LWLockRelease(&apw_state->lock);
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/*
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* Open the block dump file. Exit quietly if it doesn't exist, but report
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* any other error.
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*/
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file = AllocateFile(AUTOPREWARM_FILE, "r");
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if (!file)
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{
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if (errno == ENOENT)
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{
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LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
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apw_state->pid_using_dumpfile = InvalidPid;
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LWLockRelease(&apw_state->lock);
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return; /* No file to load. */
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}
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not read file \"%s\": %m",
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AUTOPREWARM_FILE)));
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}
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/* First line of the file is a record count. */
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if (fscanf(file, "<<" INT64_FORMAT ">>\n", &num_elements) != 1)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not read from file \"%s\": %m",
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AUTOPREWARM_FILE)));
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|
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/* Allocate a dynamic shared memory segment to store the record data. */
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seg = dsm_create(sizeof(BlockInfoRecord) * num_elements, 0);
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blkinfo = (BlockInfoRecord *) dsm_segment_address(seg);
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/* Read records, one per line. */
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for (i = 0; i < num_elements; i++)
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{
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unsigned forknum;
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if (fscanf(file, "%u,%u,%u,%u,%u\n", &blkinfo[i].database,
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&blkinfo[i].tablespace, &blkinfo[i].filenode,
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&forknum, &blkinfo[i].blocknum) != 5)
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ereport(ERROR,
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(errmsg("autoprewarm block dump file is corrupted at line " INT64_FORMAT,
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i + 1)));
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blkinfo[i].forknum = forknum;
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}
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FreeFile(file);
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/* Sort the blocks to be loaded. */
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pg_qsort(blkinfo, num_elements, sizeof(BlockInfoRecord),
|
||||||
|
apw_compare_blockinfo);
|
||||||
|
|
||||||
|
/* Populate shared memory state. */
|
||||||
|
apw_state->block_info_handle = dsm_segment_handle(seg);
|
||||||
|
apw_state->prewarm_start_idx = apw_state->prewarm_stop_idx = 0;
|
||||||
|
apw_state->prewarmed_blocks = 0;
|
||||||
|
|
||||||
|
/* Get the info position of the first block of the next database. */
|
||||||
|
while (apw_state->prewarm_start_idx < num_elements)
|
||||||
|
{
|
||||||
|
uint32 i = apw_state->prewarm_start_idx;
|
||||||
|
Oid current_db = blkinfo[i].database;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Advance the prewarm_stop_idx to the first BlockRecordInfo that does
|
||||||
|
* not belong to this database.
|
||||||
|
*/
|
||||||
|
i++;
|
||||||
|
while (i < num_elements)
|
||||||
|
{
|
||||||
|
if (current_db != blkinfo[i].database)
|
||||||
|
{
|
||||||
|
/*
|
||||||
|
* Combine BlockRecordInfos for global objects withs those of
|
||||||
|
* the database.
|
||||||
|
*/
|
||||||
|
if (current_db != InvalidOid)
|
||||||
|
break;
|
||||||
|
current_db = blkinfo[i].database;
|
||||||
|
}
|
||||||
|
|
||||||
|
i++;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* If we reach this point with current_db == InvalidOid, then only
|
||||||
|
* BlockRecordInfos belonging to global objects exist. We can't
|
||||||
|
* prewarm without a database connection, so just bail out.
|
||||||
|
*/
|
||||||
|
if (current_db == InvalidOid)
|
||||||
|
break;
|
||||||
|
|
||||||
|
/* Configure stop point and database for next per-database worker. */
|
||||||
|
apw_state->prewarm_stop_idx = i;
|
||||||
|
apw_state->database = current_db;
|
||||||
|
Assert(apw_state->prewarm_start_idx < apw_state->prewarm_stop_idx);
|
||||||
|
|
||||||
|
/* If we've run out of free buffers, don't launch another worker. */
|
||||||
|
if (!have_free_buffer())
|
||||||
|
break;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Start a per-database worker to load blocks for this database; this
|
||||||
|
* function will return once the per-database worker exits.
|
||||||
|
*/
|
||||||
|
apw_start_database_worker();
|
||||||
|
|
||||||
|
/* Prepare for next database. */
|
||||||
|
apw_state->prewarm_start_idx = apw_state->prewarm_stop_idx;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Clean up. */
|
||||||
|
dsm_detach(seg);
|
||||||
|
LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
|
||||||
|
apw_state->block_info_handle = DSM_HANDLE_INVALID;
|
||||||
|
apw_state->pid_using_dumpfile = InvalidPid;
|
||||||
|
LWLockRelease(&apw_state->lock);
|
||||||
|
|
||||||
|
/* Report our success. */
|
||||||
|
ereport(LOG,
|
||||||
|
(errmsg("autoprewarm successfully prewarmed " INT64_FORMAT
|
||||||
|
" of " INT64_FORMAT " previously-loaded blocks",
|
||||||
|
apw_state->prewarmed_blocks, num_elements)));
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Prewarm all blocks for one database (and possibly also global objects, if
|
||||||
|
* those got grouped with this database).
|
||||||
|
*/
|
||||||
|
void
|
||||||
|
autoprewarm_database_main(Datum main_arg)
|
||||||
|
{
|
||||||
|
uint32 pos;
|
||||||
|
BlockInfoRecord *block_info;
|
||||||
|
Relation rel = NULL;
|
||||||
|
BlockNumber nblocks = 0;
|
||||||
|
BlockInfoRecord *old_blk = NULL;
|
||||||
|
dsm_segment *seg;
|
||||||
|
|
||||||
|
/* Establish signal handlers; once that's done, unblock signals. */
|
||||||
|
pqsignal(SIGTERM, die);
|
||||||
|
BackgroundWorkerUnblockSignals();
|
||||||
|
|
||||||
|
/* Connect to correct database and get block information. */
|
||||||
|
apw_init_shmem();
|
||||||
|
seg = dsm_attach(apw_state->block_info_handle);
|
||||||
|
if (seg == NULL)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
||||||
|
errmsg("could not map dynamic shared memory segment")));
|
||||||
|
BackgroundWorkerInitializeConnectionByOid(apw_state->database, InvalidOid);
|
||||||
|
block_info = (BlockInfoRecord *) dsm_segment_address(seg);
|
||||||
|
pos = apw_state->prewarm_start_idx;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Loop until we run out of blocks to prewarm or until we run out of free
|
||||||
|
* buffers.
|
||||||
|
*/
|
||||||
|
while (pos < apw_state->prewarm_stop_idx && have_free_buffer())
|
||||||
|
{
|
||||||
|
BlockInfoRecord *blk = &block_info[pos++];
|
||||||
|
Buffer buf;
|
||||||
|
|
||||||
|
CHECK_FOR_INTERRUPTS();
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Quit if we've reached records for another database. If previous
|
||||||
|
* blocks are of some global objects, then continue pre-warming.
|
||||||
|
*/
|
||||||
|
if (old_blk != NULL && old_blk->database != blk->database &&
|
||||||
|
old_blk->database != 0)
|
||||||
|
break;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* As soon as we encounter a block of a new relation, close the old
|
||||||
|
* relation. Note that rel will be NULL if try_relation_open failed
|
||||||
|
* previously; in that case, there is nothing to close.
|
||||||
|
*/
|
||||||
|
if (old_blk != NULL && old_blk->filenode != blk->filenode &&
|
||||||
|
rel != NULL)
|
||||||
|
{
|
||||||
|
relation_close(rel, AccessShareLock);
|
||||||
|
rel = NULL;
|
||||||
|
CommitTransactionCommand();
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Try to open each new relation, but only once, when we first
|
||||||
|
* encounter it. If it's been dropped, skip the associated blocks.
|
||||||
|
*/
|
||||||
|
if (old_blk == NULL || old_blk->filenode != blk->filenode)
|
||||||
|
{
|
||||||
|
Oid reloid;
|
||||||
|
|
||||||
|
Assert(rel == NULL);
|
||||||
|
StartTransactionCommand();
|
||||||
|
reloid = RelidByRelfilenode(blk->tablespace, blk->filenode);
|
||||||
|
if (OidIsValid(reloid))
|
||||||
|
rel = try_relation_open(reloid, AccessShareLock);
|
||||||
|
|
||||||
|
if (!rel)
|
||||||
|
CommitTransactionCommand();
|
||||||
|
}
|
||||||
|
if (!rel)
|
||||||
|
{
|
||||||
|
old_blk = blk;
|
||||||
|
continue;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Once per fork, check for fork existence and size. */
|
||||||
|
if (old_blk == NULL ||
|
||||||
|
old_blk->filenode != blk->filenode ||
|
||||||
|
old_blk->forknum != blk->forknum)
|
||||||
|
{
|
||||||
|
RelationOpenSmgr(rel);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* smgrexists is not safe for illegal forknum, hence check whether
|
||||||
|
* the passed forknum is valid before using it in smgrexists.
|
||||||
|
*/
|
||||||
|
if (blk->forknum > InvalidForkNumber &&
|
||||||
|
blk->forknum <= MAX_FORKNUM &&
|
||||||
|
smgrexists(rel->rd_smgr, blk->forknum))
|
||||||
|
nblocks = RelationGetNumberOfBlocksInFork(rel, blk->forknum);
|
||||||
|
else
|
||||||
|
nblocks = 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Check whether blocknum is valid and within fork file size. */
|
||||||
|
if (blk->blocknum >= nblocks)
|
||||||
|
{
|
||||||
|
/* Move to next forknum. */
|
||||||
|
old_blk = blk;
|
||||||
|
continue;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Prewarm buffer. */
|
||||||
|
buf = ReadBufferExtended(rel, blk->forknum, blk->blocknum, RBM_NORMAL,
|
||||||
|
NULL);
|
||||||
|
if (BufferIsValid(buf))
|
||||||
|
{
|
||||||
|
apw_state->prewarmed_blocks++;
|
||||||
|
ReleaseBuffer(buf);
|
||||||
|
}
|
||||||
|
|
||||||
|
old_blk = blk;
|
||||||
|
}
|
||||||
|
|
||||||
|
dsm_detach(seg);
|
||||||
|
|
||||||
|
/* Release lock on previous relation. */
|
||||||
|
if (rel)
|
||||||
|
{
|
||||||
|
relation_close(rel, AccessShareLock);
|
||||||
|
CommitTransactionCommand();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Dump information on blocks in shared buffers. We use a text format here
|
||||||
|
* so that it's easy to understand and even change the file contents if
|
||||||
|
* necessary.
|
||||||
|
*/
|
||||||
|
static int64
|
||||||
|
apw_dump_now(bool is_bgworker, bool dump_unlogged)
|
||||||
|
{
|
||||||
|
uint32 i;
|
||||||
|
int ret;
|
||||||
|
int64 num_blocks;
|
||||||
|
BlockInfoRecord *block_info_array;
|
||||||
|
BufferDesc *bufHdr;
|
||||||
|
FILE *file;
|
||||||
|
char transient_dump_file_path[MAXPGPATH];
|
||||||
|
pid_t pid;
|
||||||
|
|
||||||
|
LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
|
||||||
|
pid = apw_state->pid_using_dumpfile;
|
||||||
|
if (apw_state->pid_using_dumpfile == InvalidPid)
|
||||||
|
apw_state->pid_using_dumpfile = MyProcPid;
|
||||||
|
LWLockRelease(&apw_state->lock);
|
||||||
|
|
||||||
|
if (pid != InvalidPid)
|
||||||
|
{
|
||||||
|
if (!is_bgworker)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errmsg("could not perform block dump because dump file is being used by PID %d",
|
||||||
|
apw_state->pid_using_dumpfile)));
|
||||||
|
|
||||||
|
ereport(LOG,
|
||||||
|
(errmsg("skipping block dump because it is already being performed by PID %d",
|
||||||
|
apw_state->pid_using_dumpfile)));
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
block_info_array =
|
||||||
|
(BlockInfoRecord *) palloc(sizeof(BlockInfoRecord) * NBuffers);
|
||||||
|
|
||||||
|
for (num_blocks = 0, i = 0; i < NBuffers; i++)
|
||||||
|
{
|
||||||
|
uint32 buf_state;
|
||||||
|
|
||||||
|
CHECK_FOR_INTERRUPTS();
|
||||||
|
|
||||||
|
bufHdr = GetBufferDescriptor(i);
|
||||||
|
|
||||||
|
/* Lock each buffer header before inspecting. */
|
||||||
|
buf_state = LockBufHdr(bufHdr);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Unlogged tables will be automatically truncated after a crash or
|
||||||
|
* unclean shutdown. In such cases we need not prewarm them. Dump them
|
||||||
|
* only if requested by caller.
|
||||||
|
*/
|
||||||
|
if (buf_state & BM_TAG_VALID &&
|
||||||
|
((buf_state & BM_PERMANENT) || dump_unlogged))
|
||||||
|
{
|
||||||
|
block_info_array[num_blocks].database = bufHdr->tag.rnode.dbNode;
|
||||||
|
block_info_array[num_blocks].tablespace = bufHdr->tag.rnode.spcNode;
|
||||||
|
block_info_array[num_blocks].filenode = bufHdr->tag.rnode.relNode;
|
||||||
|
block_info_array[num_blocks].forknum = bufHdr->tag.forkNum;
|
||||||
|
block_info_array[num_blocks].blocknum = bufHdr->tag.blockNum;
|
||||||
|
++num_blocks;
|
||||||
|
}
|
||||||
|
|
||||||
|
UnlockBufHdr(bufHdr, buf_state);
|
||||||
|
}
|
||||||
|
|
||||||
|
snprintf(transient_dump_file_path, MAXPGPATH, "%s.tmp", AUTOPREWARM_FILE);
|
||||||
|
file = AllocateFile(transient_dump_file_path, "w");
|
||||||
|
if (!file)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode_for_file_access(),
|
||||||
|
errmsg("could not open file \"%s\": %m",
|
||||||
|
transient_dump_file_path)));
|
||||||
|
|
||||||
|
ret = fprintf(file, "<<" INT64_FORMAT ">>\n", num_blocks);
|
||||||
|
if (ret < 0)
|
||||||
|
{
|
||||||
|
int save_errno = errno;
|
||||||
|
|
||||||
|
FreeFile(file);
|
||||||
|
unlink(transient_dump_file_path);
|
||||||
|
errno = save_errno;
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode_for_file_access(),
|
||||||
|
errmsg("could not write to file \"%s\" : %m",
|
||||||
|
transient_dump_file_path)));
|
||||||
|
}
|
||||||
|
|
||||||
|
for (i = 0; i < num_blocks; i++)
|
||||||
|
{
|
||||||
|
CHECK_FOR_INTERRUPTS();
|
||||||
|
|
||||||
|
ret = fprintf(file, "%u,%u,%u,%u,%u\n",
|
||||||
|
block_info_array[i].database,
|
||||||
|
block_info_array[i].tablespace,
|
||||||
|
block_info_array[i].filenode,
|
||||||
|
(uint32) block_info_array[i].forknum,
|
||||||
|
block_info_array[i].blocknum);
|
||||||
|
if (ret < 0)
|
||||||
|
{
|
||||||
|
int save_errno = errno;
|
||||||
|
|
||||||
|
FreeFile(file);
|
||||||
|
unlink(transient_dump_file_path);
|
||||||
|
errno = save_errno;
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode_for_file_access(),
|
||||||
|
errmsg("could not write to file \"%s\" : %m",
|
||||||
|
transient_dump_file_path)));
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
pfree(block_info_array);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Rename transient_dump_file_path to AUTOPREWARM_FILE to make things
|
||||||
|
* permanent.
|
||||||
|
*/
|
||||||
|
ret = FreeFile(file);
|
||||||
|
if (ret != 0)
|
||||||
|
{
|
||||||
|
int save_errno = errno;
|
||||||
|
|
||||||
|
unlink(transient_dump_file_path);
|
||||||
|
errno = save_errno;
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode_for_file_access(),
|
||||||
|
errmsg("could not close file \"%s\" : %m",
|
||||||
|
transient_dump_file_path)));
|
||||||
|
}
|
||||||
|
|
||||||
|
(void) durable_rename(transient_dump_file_path, AUTOPREWARM_FILE, ERROR);
|
||||||
|
apw_state->pid_using_dumpfile = InvalidPid;
|
||||||
|
|
||||||
|
ereport(DEBUG1,
|
||||||
|
(errmsg("wrote block details for " INT64_FORMAT " blocks",
|
||||||
|
num_blocks)));
|
||||||
|
return num_blocks;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* SQL-callable function to launch autoprewarm.
|
||||||
|
*/
|
||||||
|
Datum
|
||||||
|
autoprewarm_start_worker(PG_FUNCTION_ARGS)
|
||||||
|
{
|
||||||
|
pid_t pid;
|
||||||
|
|
||||||
|
if (!autoprewarm)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
||||||
|
errmsg("autoprewarm is disabled")));
|
||||||
|
|
||||||
|
apw_init_shmem();
|
||||||
|
LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
|
||||||
|
pid = apw_state->bgworker_pid;
|
||||||
|
LWLockRelease(&apw_state->lock);
|
||||||
|
|
||||||
|
if (pid != InvalidPid)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
||||||
|
errmsg("autoprewarm worker is already running under PID %d",
|
||||||
|
pid)));
|
||||||
|
|
||||||
|
apw_start_master_worker();
|
||||||
|
|
||||||
|
PG_RETURN_VOID();
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* SQL-callable function to perform an immediate block dump.
|
||||||
|
*/
|
||||||
|
Datum
|
||||||
|
autoprewarm_dump_now(PG_FUNCTION_ARGS)
|
||||||
|
{
|
||||||
|
int64 num_blocks;
|
||||||
|
|
||||||
|
apw_init_shmem();
|
||||||
|
|
||||||
|
PG_ENSURE_ERROR_CLEANUP(apw_detach_shmem, 0);
|
||||||
|
{
|
||||||
|
num_blocks = apw_dump_now(false, true);
|
||||||
|
}
|
||||||
|
PG_END_ENSURE_ERROR_CLEANUP(apw_detach_shmem, 0);
|
||||||
|
|
||||||
|
PG_RETURN_INT64(num_blocks);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Allocate and initialize autoprewarm related shared memory, if not already
|
||||||
|
* done, and set up backend-local pointer to that state. Returns true if an
|
||||||
|
* existing shared memory segment was found.
|
||||||
|
*/
|
||||||
|
static bool
|
||||||
|
apw_init_shmem(void)
|
||||||
|
{
|
||||||
|
bool found;
|
||||||
|
|
||||||
|
LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
|
||||||
|
apw_state = ShmemInitStruct("autoprewarm",
|
||||||
|
sizeof(AutoPrewarmSharedState),
|
||||||
|
&found);
|
||||||
|
if (!found)
|
||||||
|
{
|
||||||
|
/* First time through ... */
|
||||||
|
LWLockInitialize(&apw_state->lock, LWLockNewTrancheId());
|
||||||
|
apw_state->bgworker_pid = InvalidPid;
|
||||||
|
apw_state->pid_using_dumpfile = InvalidPid;
|
||||||
|
}
|
||||||
|
LWLockRelease(AddinShmemInitLock);
|
||||||
|
|
||||||
|
return found;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Clear our PID from autoprewarm shared state.
|
||||||
|
*/
|
||||||
|
static void
|
||||||
|
apw_detach_shmem(int code, Datum arg)
|
||||||
|
{
|
||||||
|
LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
|
||||||
|
if (apw_state->pid_using_dumpfile == MyProcPid)
|
||||||
|
apw_state->pid_using_dumpfile = InvalidPid;
|
||||||
|
if (apw_state->bgworker_pid == MyProcPid)
|
||||||
|
apw_state->bgworker_pid = InvalidPid;
|
||||||
|
LWLockRelease(&apw_state->lock);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Start autoprewarm master worker process.
|
||||||
|
*/
|
||||||
|
static void
|
||||||
|
apw_start_master_worker(void)
|
||||||
|
{
|
||||||
|
BackgroundWorker worker;
|
||||||
|
BackgroundWorkerHandle *handle;
|
||||||
|
BgwHandleStatus status;
|
||||||
|
pid_t pid;
|
||||||
|
|
||||||
|
MemSet(&worker, 0, sizeof(BackgroundWorker));
|
||||||
|
worker.bgw_flags = BGWORKER_SHMEM_ACCESS;
|
||||||
|
worker.bgw_start_time = BgWorkerStart_ConsistentState;
|
||||||
|
strcpy(worker.bgw_library_name, "pg_prewarm");
|
||||||
|
strcpy(worker.bgw_function_name, "autoprewarm_main");
|
||||||
|
strcpy(worker.bgw_name, "autoprewarm");
|
||||||
|
|
||||||
|
if (process_shared_preload_libraries_in_progress)
|
||||||
|
{
|
||||||
|
RegisterBackgroundWorker(&worker);
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* must set notify PID to wait for startup */
|
||||||
|
worker.bgw_notify_pid = MyProcPid;
|
||||||
|
|
||||||
|
if (!RegisterDynamicBackgroundWorker(&worker, &handle))
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
||||||
|
errmsg("could not register background process"),
|
||||||
|
errhint("You may need to increase max_worker_processes.")));
|
||||||
|
|
||||||
|
status = WaitForBackgroundWorkerStartup(handle, &pid);
|
||||||
|
if (status != BGWH_STARTED)
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
||||||
|
errmsg("could not start background process"),
|
||||||
|
errhint("More details may be available in the server log.")));
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Start autoprewarm per-database worker process.
|
||||||
|
*/
|
||||||
|
static void
|
||||||
|
apw_start_database_worker(void)
|
||||||
|
{
|
||||||
|
BackgroundWorker worker;
|
||||||
|
BackgroundWorkerHandle *handle;
|
||||||
|
|
||||||
|
MemSet(&worker, 0, sizeof(BackgroundWorker));
|
||||||
|
worker.bgw_flags =
|
||||||
|
BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION;
|
||||||
|
worker.bgw_start_time = BgWorkerStart_ConsistentState;
|
||||||
|
strcpy(worker.bgw_library_name, "pg_prewarm");
|
||||||
|
strcpy(worker.bgw_function_name, "autoprewarm_database_main");
|
||||||
|
strcpy(worker.bgw_name, "autoprewarm");
|
||||||
|
|
||||||
|
/* must set notify PID to wait for shutdown */
|
||||||
|
worker.bgw_notify_pid = MyProcPid;
|
||||||
|
|
||||||
|
if (!RegisterDynamicBackgroundWorker(&worker, &handle))
|
||||||
|
ereport(ERROR,
|
||||||
|
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
|
||||||
|
errmsg("registering dynamic bgworker autoprewarm failed"),
|
||||||
|
errhint("Consider increasing configuration parameter \"max_worker_processes\".")));
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Ignore return value; if it fails, postmaster has died, but we have
|
||||||
|
* checks for that elsewhere.
|
||||||
|
*/
|
||||||
|
WaitForBackgroundWorkerShutdown(handle);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Compare member elements to check whether they are not equal. */
|
||||||
|
#define cmp_member_elem(fld) \
|
||||||
|
do { \
|
||||||
|
if (a->fld < b->fld) \
|
||||||
|
return -1; \
|
||||||
|
else if (a->fld > b->fld) \
|
||||||
|
return 1; \
|
||||||
|
} while(0);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* apw_compare_blockinfo
|
||||||
|
*
|
||||||
|
* We depend on all records for a particular database being consecutive
|
||||||
|
* in the dump file; each per-database worker will preload blocks until
|
||||||
|
* it sees a block for some other database. Sorting by tablespace,
|
||||||
|
* filenode, forknum, and blocknum isn't critical for correctness, but
|
||||||
|
* helps us get a sequential I/O pattern.
|
||||||
|
*/
|
||||||
|
static int
|
||||||
|
apw_compare_blockinfo(const void *p, const void *q)
|
||||||
|
{
|
||||||
|
BlockInfoRecord *a = (BlockInfoRecord *) p;
|
||||||
|
BlockInfoRecord *b = (BlockInfoRecord *) q;
|
||||||
|
|
||||||
|
cmp_member_elem(database);
|
||||||
|
cmp_member_elem(tablespace);
|
||||||
|
cmp_member_elem(filenode);
|
||||||
|
cmp_member_elem(forknum);
|
||||||
|
cmp_member_elem(blocknum);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Signal handler for SIGTERM
|
||||||
|
*/
|
||||||
|
static void
|
||||||
|
apw_sigterm_handler(SIGNAL_ARGS)
|
||||||
|
{
|
||||||
|
int save_errno = errno;
|
||||||
|
|
||||||
|
got_sigterm = true;
|
||||||
|
|
||||||
|
if (MyProc)
|
||||||
|
SetLatch(&MyProc->procLatch);
|
||||||
|
|
||||||
|
errno = save_errno;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Signal handler for SIGHUP
|
||||||
|
*/
|
||||||
|
static void
|
||||||
|
apw_sighup_handler(SIGNAL_ARGS)
|
||||||
|
{
|
||||||
|
int save_errno = errno;
|
||||||
|
|
||||||
|
got_sighup = true;
|
||||||
|
|
||||||
|
if (MyProc)
|
||||||
|
SetLatch(&MyProc->procLatch);
|
||||||
|
|
||||||
|
errno = save_errno;
|
||||||
|
}
|
||||||
14
contrib/pg_prewarm/pg_prewarm--1.1--1.2.sql
Normal file
14
contrib/pg_prewarm/pg_prewarm--1.1--1.2.sql
Normal file
@ -0,0 +1,14 @@
|
|||||||
|
/* contrib/pg_prewarm/pg_prewarm--1.1--1.2.sql */
|
||||||
|
|
||||||
|
-- complain if script is sourced in psql, rather than via ALTER EXTENSION
|
||||||
|
\echo Use "ALTER EXTENSION pg_prewarm UPDATE TO '1.2'" to load this file. \quit
|
||||||
|
|
||||||
|
CREATE FUNCTION autoprewarm_start_worker()
|
||||||
|
RETURNS VOID STRICT
|
||||||
|
AS 'MODULE_PATHNAME', 'autoprewarm_start_worker'
|
||||||
|
LANGUAGE C;
|
||||||
|
|
||||||
|
CREATE FUNCTION autoprewarm_dump_now()
|
||||||
|
RETURNS pg_catalog.int8 STRICT
|
||||||
|
AS 'MODULE_PATHNAME', 'autoprewarm_dump_now'
|
||||||
|
LANGUAGE C;
|
||||||
@ -1,5 +1,5 @@
|
|||||||
# pg_prewarm extension
|
# pg_prewarm extension
|
||||||
comment = 'prewarm relation data'
|
comment = 'prewarm relation data'
|
||||||
default_version = '1.1'
|
default_version = '1.2'
|
||||||
module_pathname = '$libdir/pg_prewarm'
|
module_pathname = '$libdir/pg_prewarm'
|
||||||
relocatable = true
|
relocatable = true
|
||||||
|
|||||||
@ -10,7 +10,13 @@
|
|||||||
<para>
|
<para>
|
||||||
The <filename>pg_prewarm</filename> module provides a convenient way
|
The <filename>pg_prewarm</filename> module provides a convenient way
|
||||||
to load relation data into either the operating system buffer cache
|
to load relation data into either the operating system buffer cache
|
||||||
or the <productname>PostgreSQL</productname> buffer cache.
|
or the <productname>PostgreSQL</productname> buffer cache. Prewarming
|
||||||
|
can be performed manually using the <filename>pg_prewarm</> function,
|
||||||
|
or can be performed automatically by including <literal>pg_prewarm</> in
|
||||||
|
<xref linkend="guc-shared-preload-libraries">. In the latter case, the
|
||||||
|
system will run a background worker which periodically records the contents
|
||||||
|
of shared buffers in a file called <filename>autoprewarm.blocks</> and
|
||||||
|
will, using 2 background workers, reload those same blocks after a restart.
|
||||||
</para>
|
</para>
|
||||||
|
|
||||||
<sect2>
|
<sect2>
|
||||||
@ -55,6 +61,67 @@ pg_prewarm(regclass, mode text default 'buffer', fork text default 'main',
|
|||||||
cache. For these reasons, prewarming is typically most useful at startup,
|
cache. For these reasons, prewarming is typically most useful at startup,
|
||||||
when caches are largely empty.
|
when caches are largely empty.
|
||||||
</para>
|
</para>
|
||||||
|
|
||||||
|
<synopsis>
|
||||||
|
autoprewarm_start_worker() RETURNS void
|
||||||
|
</synopsis>
|
||||||
|
|
||||||
|
<para>
|
||||||
|
Launch the main autoprewarm worker. This will normally happen
|
||||||
|
automatically, but is useful if automatic prewarm was not configured at
|
||||||
|
server startup time and you wish to start up the worker at a later time.
|
||||||
|
</para>
|
||||||
|
|
||||||
|
<synopsis>
|
||||||
|
autoprewarm_dump_now() RETURNS int8
|
||||||
|
</synopsis>
|
||||||
|
|
||||||
|
<para>
|
||||||
|
Update <filename>autoprewarm.blocks</> immediately. This may be useful
|
||||||
|
if the autoprewarm worker is not running but you anticipate running it
|
||||||
|
after the next restart. The return value is the number of records written
|
||||||
|
to <filename>autoprewarm.blocks</>.
|
||||||
|
</para>
|
||||||
|
</sect2>
|
||||||
|
|
||||||
|
<sect2>
|
||||||
|
<title>Configuration Parameters</title>
|
||||||
|
|
||||||
|
<variablelist>
|
||||||
|
<varlistentry>
|
||||||
|
<term>
|
||||||
|
<varname>pg_prewarm.autoprewarm</varname> (<type>boolean</type>)
|
||||||
|
<indexterm>
|
||||||
|
<primary><varname>pg_prewarm.autoprewarm</> configuration parameter</primary>
|
||||||
|
</indexterm>
|
||||||
|
</term>
|
||||||
|
<listitem>
|
||||||
|
<para>
|
||||||
|
Controls whether the server should run the autoprewarm worker. This is
|
||||||
|
on by default. This parameter can only be set at server start.
|
||||||
|
</para>
|
||||||
|
</listitem>
|
||||||
|
</varlistentry>
|
||||||
|
</variablelist>
|
||||||
|
|
||||||
|
<variablelist>
|
||||||
|
<varlistentry>
|
||||||
|
<term>
|
||||||
|
<varname>pg_prewarm.autoprewarm_interval</varname> (<type>int</type>)
|
||||||
|
<indexterm>
|
||||||
|
<primary><varname>pg_prewarm.autoprewarm_interval</> configuration parameter</primary>
|
||||||
|
</indexterm>
|
||||||
|
</term>
|
||||||
|
<listitem>
|
||||||
|
<para>
|
||||||
|
This is the interval between updates to <literal>autoprewarm.blocks</>.
|
||||||
|
The default is 300 seconds. If set to 0, the file will not be
|
||||||
|
dumped at regular intervals, but only when the server is shut down.
|
||||||
|
</para>
|
||||||
|
</listitem>
|
||||||
|
</varlistentry>
|
||||||
|
</variablelist>
|
||||||
|
|
||||||
</sect2>
|
</sect2>
|
||||||
|
|
||||||
<sect2>
|
<sect2>
|
||||||
|
|||||||
@ -168,6 +168,23 @@ ClockSweepTick(void)
|
|||||||
return victim;
|
return victim;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* have_free_buffer -- a lockless check to see if there is a free buffer in
|
||||||
|
* buffer pool.
|
||||||
|
*
|
||||||
|
* If the result is true that will become stale once free buffers are moved out
|
||||||
|
* by other operations, so the caller who strictly want to use a free buffer
|
||||||
|
* should not call this.
|
||||||
|
*/
|
||||||
|
bool
|
||||||
|
have_free_buffer()
|
||||||
|
{
|
||||||
|
if (StrategyControl->firstFreeBuffer >= 0)
|
||||||
|
return true;
|
||||||
|
else
|
||||||
|
return false;
|
||||||
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* StrategyGetBuffer
|
* StrategyGetBuffer
|
||||||
*
|
*
|
||||||
|
|||||||
@ -317,6 +317,7 @@ extern void StrategyNotifyBgWriter(int bgwprocno);
|
|||||||
|
|
||||||
extern Size StrategyShmemSize(void);
|
extern Size StrategyShmemSize(void);
|
||||||
extern void StrategyInitialize(bool init);
|
extern void StrategyInitialize(bool init);
|
||||||
|
extern bool have_free_buffer(void);
|
||||||
|
|
||||||
/* buf_table.c */
|
/* buf_table.c */
|
||||||
extern Size BufTableShmemSize(int size);
|
extern Size BufTableShmemSize(int size);
|
||||||
|
|||||||
@ -138,6 +138,7 @@ AttrDefault
|
|||||||
AttrNumber
|
AttrNumber
|
||||||
AttributeOpts
|
AttributeOpts
|
||||||
AuthRequest
|
AuthRequest
|
||||||
|
AutoPrewarmSharedState
|
||||||
AutoVacOpts
|
AutoVacOpts
|
||||||
AutoVacuumShmemStruct
|
AutoVacuumShmemStruct
|
||||||
AutoVacuumWorkItem
|
AutoVacuumWorkItem
|
||||||
@ -218,6 +219,7 @@ BlobInfo
|
|||||||
Block
|
Block
|
||||||
BlockId
|
BlockId
|
||||||
BlockIdData
|
BlockIdData
|
||||||
|
BlockInfoRecord
|
||||||
BlockNumber
|
BlockNumber
|
||||||
BlockSampler
|
BlockSampler
|
||||||
BlockSamplerData
|
BlockSamplerData
|
||||||
|
|||||||
Loading…
x
Reference in New Issue
Block a user