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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
925 lines
24 KiB
C
925 lines
24 KiB
C
/*-------------------------------------------------------------------------
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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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/* 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),
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apw_compare_blockinfo);
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/* Populate shared memory state. */
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apw_state->block_info_handle = dsm_segment_handle(seg);
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apw_state->prewarm_start_idx = apw_state->prewarm_stop_idx = 0;
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apw_state->prewarmed_blocks = 0;
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/* Get the info position of the first block of the next database. */
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while (apw_state->prewarm_start_idx < num_elements)
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{
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uint32 i = apw_state->prewarm_start_idx;
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Oid current_db = blkinfo[i].database;
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/*
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* Advance the prewarm_stop_idx to the first BlockRecordInfo that does
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* not belong to this database.
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*/
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i++;
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while (i < num_elements)
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{
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if (current_db != blkinfo[i].database)
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{
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/*
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* Combine BlockRecordInfos for global objects withs those of
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* the database.
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*/
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if (current_db != InvalidOid)
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break;
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current_db = blkinfo[i].database;
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}
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i++;
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}
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/*
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* If we reach this point with current_db == InvalidOid, then only
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* BlockRecordInfos belonging to global objects exist. We can't
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* prewarm without a database connection, so just bail out.
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*/
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if (current_db == InvalidOid)
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break;
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/* Configure stop point and database for next per-database worker. */
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apw_state->prewarm_stop_idx = i;
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apw_state->database = current_db;
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Assert(apw_state->prewarm_start_idx < apw_state->prewarm_stop_idx);
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/* If we've run out of free buffers, don't launch another worker. */
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if (!have_free_buffer())
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break;
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/*
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* Start a per-database worker to load blocks for this database; this
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* function will return once the per-database worker exits.
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*/
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apw_start_database_worker();
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/* Prepare for next database. */
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apw_state->prewarm_start_idx = apw_state->prewarm_stop_idx;
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}
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/* Clean up. */
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dsm_detach(seg);
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LWLockAcquire(&apw_state->lock, LW_EXCLUSIVE);
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apw_state->block_info_handle = DSM_HANDLE_INVALID;
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apw_state->pid_using_dumpfile = InvalidPid;
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LWLockRelease(&apw_state->lock);
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/* Report our success. */
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ereport(LOG,
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(errmsg("autoprewarm successfully prewarmed " INT64_FORMAT
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" of " INT64_FORMAT " previously-loaded blocks",
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apw_state->prewarmed_blocks, num_elements)));
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}
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/*
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* Prewarm all blocks for one database (and possibly also global objects, if
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* those got grouped with this database).
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*/
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void
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autoprewarm_database_main(Datum main_arg)
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{
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uint32 pos;
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BlockInfoRecord *block_info;
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Relation rel = NULL;
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BlockNumber nblocks = 0;
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BlockInfoRecord *old_blk = NULL;
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dsm_segment *seg;
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/* Establish signal handlers; once that's done, unblock signals. */
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pqsignal(SIGTERM, die);
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BackgroundWorkerUnblockSignals();
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/* Connect to correct database and get block information. */
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apw_init_shmem();
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seg = dsm_attach(apw_state->block_info_handle);
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if (seg == NULL)
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ereport(ERROR,
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(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
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errmsg("could not map dynamic shared memory segment")));
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BackgroundWorkerInitializeConnectionByOid(apw_state->database, InvalidOid);
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block_info = (BlockInfoRecord *) dsm_segment_address(seg);
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pos = apw_state->prewarm_start_idx;
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/*
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* Loop until we run out of blocks to prewarm or until we run out of free
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* buffers.
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*/
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while (pos < apw_state->prewarm_stop_idx && have_free_buffer())
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{
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BlockInfoRecord *blk = &block_info[pos++];
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Buffer buf;
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CHECK_FOR_INTERRUPTS();
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/*
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* Quit if we've reached records for another database. If previous
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* blocks are of some global objects, then continue pre-warming.
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*/
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if (old_blk != NULL && old_blk->database != blk->database &&
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old_blk->database != 0)
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break;
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/*
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* As soon as we encounter a block of a new relation, close the old
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* relation. Note that rel will be NULL if try_relation_open failed
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* previously; in that case, there is nothing to close.
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*/
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if (old_blk != NULL && old_blk->filenode != blk->filenode &&
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rel != NULL)
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{
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relation_close(rel, AccessShareLock);
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rel = NULL;
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CommitTransactionCommand();
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}
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/*
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* Try to open each new relation, but only once, when we first
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* encounter it. If it's been dropped, skip the associated blocks.
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*/
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if (old_blk == NULL || old_blk->filenode != blk->filenode)
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{
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Oid reloid;
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Assert(rel == NULL);
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StartTransactionCommand();
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reloid = RelidByRelfilenode(blk->tablespace, blk->filenode);
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if (OidIsValid(reloid))
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rel = try_relation_open(reloid, AccessShareLock);
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if (!rel)
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CommitTransactionCommand();
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}
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if (!rel)
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{
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old_blk = blk;
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continue;
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}
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/* Once per fork, check for fork existence and size. */
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if (old_blk == NULL ||
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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;
|
|
}
|