worker_spi.c File Reference

#include "postgres.h"
#include "miscadmin.h"
#include "postmaster/bgworker.h"
#include "postmaster/interrupt.h"
#include "storage/ipc.h"
#include "storage/latch.h"
#include "storage/lwlock.h"
#include "storage/proc.h"
#include "storage/shmem.h"
#include "access/xact.h"
#include "executor/spi.h"
#include "fmgr.h"
#include "lib/stringinfo.h"
#include "pgstat.h"
#include "utils/builtins.h"
#include "utils/snapmgr.h"
#include "tcop/utility.h"

Include dependency graph for worker_spi.c:

Go to the source code of this file.

Functions
	PG_FUNCTION_INFO_V1 (worker_spi_launch)
void	_PG_init (void)
void	worker_spi_main (Datum)
static void	initialize_worker_spi (worktable *table)
Datum	worker_spi_launch (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC
	worktable

Function Documentation

_PG_init()

void _PG_init

(

void

)

Definition at line 282 of file worker_spi.c.

{
    BackgroundWorker worker;
 
    /* get the configuration */
    DefineCustomIntVariable("worker_spi.naptime",
                            "Duration between each check (in seconds).",
                            NULL,
                            &worker_spi_naptime,
                            10,
                            1,
                            INT_MAX,
                            PGC_SIGHUP,
                            0,
                            NULL,
                            NULL,
                            NULL);
 
    if (!process_shared_preload_libraries_in_progress)
        return;
 
    DefineCustomIntVariable("worker_spi.total_workers",
                            "Number of workers.",
                            NULL,
                            &worker_spi_total_workers,
                            2,
                            1,
                            100,
                            PGC_POSTMASTER,
                            0,
                            NULL,
                            NULL,
                            NULL);
 
    DefineCustomStringVariable("worker_spi.database",
                               "Database to connect to.",
                               NULL,
                               &worker_spi_database,
                               "postgres",
                               PGC_POSTMASTER,
                               0,
                               NULL, NULL, NULL);
 
    MarkGUCPrefixReserved("worker_spi");
 
    /* set up common data for all our workers */
    memset(&worker, 0, sizeof(worker));
    worker.bgw_flags = BGWORKER_SHMEM_ACCESS |
        BGWORKER_BACKEND_DATABASE_CONNECTION;
    worker.bgw_start_time = BgWorkerStart_RecoveryFinished;
    worker.bgw_restart_time = BGW_NEVER_RESTART;
    sprintf(worker.bgw_library_name, "worker_spi");
    sprintf(worker.bgw_function_name, "worker_spi_main");
    worker.bgw_notify_pid = 0;
 
    /*
     * Now fill in worker-specific data, and do the actual registrations.
     */
    for (int i = 1; i <= worker_spi_total_workers; i++)
    {
        snprintf(worker.bgw_name, BGW_MAXLEN, "worker_spi worker %d", i);
        snprintf(worker.bgw_type, BGW_MAXLEN, "worker_spi");
        worker.bgw_main_arg = Int32GetDatum(i);
 
        RegisterBackgroundWorker(&worker);
    }
}

References BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BGW_MAXLEN, BackgroundWorker::bgw_name, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BackgroundWorker::bgw_type, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_SHMEM_ACCESS, BgWorkerStart_RecoveryFinished, DefineCustomIntVariable(), DefineCustomStringVariable(), i, Int32GetDatum, MarkGUCPrefixReserved(), PGC_POSTMASTER, PGC_SIGHUP, process_shared_preload_libraries_in_progress, RegisterBackgroundWorker(), snprintf, and sprintf.

initialize_worker_spi()

static void initialize_worker_spi ( worktable *  table )

static

Definition at line 69 of file worker_spi.c.

{
    int         ret;
    int         ntup;
    bool        isnull;
    StringInfoData buf;
 
    SetCurrentStatementStartTimestamp();
    StartTransactionCommand();
    SPI_connect();
    PushActiveSnapshot(GetTransactionSnapshot());
    pgstat_report_activity(STATE_RUNNING, "initializing worker_spi schema");
 
    /* XXX could we use CREATE SCHEMA IF NOT EXISTS? */
    initStringInfo(&buf);
    appendStringInfo(&buf, "select count(*) from pg_namespace where nspname = '%s'",
                     table->schema);
 
    debug_query_string = buf.data;
    ret = SPI_execute(buf.data, true, 0);
    if (ret != SPI_OK_SELECT)
        elog(FATAL, "SPI_execute failed: error code %d", ret);
 
    if (SPI_processed != 1)
        elog(FATAL, "not a singleton result");
 
    ntup = DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0],
                                       SPI_tuptable->tupdesc,
                                       1, &isnull));
    if (isnull)
        elog(FATAL, "null result");
 
    if (ntup == 0)
    {
        debug_query_string = NULL;
        resetStringInfo(&buf);
        appendStringInfo(&buf,
                         "CREATE SCHEMA \"%s\" "
                         "CREATE TABLE \"%s\" ("
                         "      type text CHECK (type IN ('total', 'delta')), "
                         "      value   integer)"
                         "CREATE UNIQUE INDEX \"%s_unique_total\" ON \"%s\" (type) "
                         "WHERE type = 'total'",
                         table->schema, table->name, table->name, table->name);
 
        /* set statement start time */
        SetCurrentStatementStartTimestamp();
 
        debug_query_string = buf.data;
        ret = SPI_execute(buf.data, false, 0);
 
        if (ret != SPI_OK_UTILITY)
            elog(FATAL, "failed to create my schema");
 
        debug_query_string = NULL;  /* rest is not statement-specific */
    }
 
    SPI_finish();
    PopActiveSnapshot();
    CommitTransactionCommand();
    debug_query_string = NULL;
    pgstat_report_activity(STATE_IDLE, NULL);
}

References appendStringInfo(), buf, CommitTransactionCommand(), DatumGetInt64, debug_query_string, elog, FATAL, GetTransactionSnapshot(), initStringInfo(), pgstat_report_activity(), PopActiveSnapshot(), PushActiveSnapshot(), resetStringInfo(), SetCurrentStatementStartTimestamp(), SPI_connect(), SPI_execute(), SPI_finish(), SPI_getbinval(), SPI_OK_SELECT, SPI_OK_UTILITY, SPI_processed, SPI_tuptable, StartTransactionCommand(), STATE_IDLE, STATE_RUNNING, SPITupleTable::tupdesc, and SPITupleTable::vals.

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

worker_spi_launch

)

worker_spi_launch()

Datum worker_spi_launch

(

PG_FUNCTION_ARGS

)

Definition at line 354 of file worker_spi.c.

{
    int32       i = PG_GETARG_INT32(0);
    BackgroundWorker worker;
    BackgroundWorkerHandle *handle;
    BgwHandleStatus status;
    pid_t       pid;
 
    memset(&worker, 0, sizeof(worker));
    worker.bgw_flags = BGWORKER_SHMEM_ACCESS |
        BGWORKER_BACKEND_DATABASE_CONNECTION;
    worker.bgw_start_time = BgWorkerStart_RecoveryFinished;
    worker.bgw_restart_time = BGW_NEVER_RESTART;
    sprintf(worker.bgw_library_name, "worker_spi");
    sprintf(worker.bgw_function_name, "worker_spi_main");
    snprintf(worker.bgw_name, BGW_MAXLEN, "worker_spi worker %d", i);
    snprintf(worker.bgw_type, BGW_MAXLEN, "worker_spi");
    worker.bgw_main_arg = Int32GetDatum(i);
    /* set bgw_notify_pid so that we can use WaitForBackgroundWorkerStartup */
    worker.bgw_notify_pid = MyProcPid;
 
    if (!RegisterDynamicBackgroundWorker(&worker, &handle))
        PG_RETURN_NULL();
 
    status = WaitForBackgroundWorkerStartup(handle, &pid);
 
    if (status == BGWH_STOPPED)
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("could not start background process"),
                 errhint("More details may be available in the server log.")));
    if (status == BGWH_POSTMASTER_DIED)
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
                 errmsg("cannot start background processes without postmaster"),
                 errhint("Kill all remaining database processes and restart the database.")));
    Assert(status == BGWH_STARTED);
 
    PG_RETURN_INT32(pid);
}

References Assert(), BackgroundWorker::bgw_flags, BackgroundWorker::bgw_function_name, BackgroundWorker::bgw_library_name, BackgroundWorker::bgw_main_arg, BGW_MAXLEN, BackgroundWorker::bgw_name, BGW_NEVER_RESTART, BackgroundWorker::bgw_notify_pid, BackgroundWorker::bgw_restart_time, BackgroundWorker::bgw_start_time, BackgroundWorker::bgw_type, BGWH_POSTMASTER_DIED, BGWH_STARTED, BGWH_STOPPED, BGWORKER_BACKEND_DATABASE_CONNECTION, BGWORKER_SHMEM_ACCESS, BgWorkerStart_RecoveryFinished, ereport, errcode(), errhint(), errmsg(), ERROR, i, Int32GetDatum, MyProcPid, PG_GETARG_INT32, PG_RETURN_INT32, PG_RETURN_NULL, RegisterDynamicBackgroundWorker(), snprintf, sprintf, status(), and WaitForBackgroundWorkerStartup().

worker_spi_main()

void worker_spi_main

(

Datum

main_arg

)

Definition at line 50 of file worker_spi.c.

{
    const char *schema;
    const char *name;
} worktable;

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 45 of file worker_spi.c.

worktable

worktable

Definition at line 62 of file worker_spi.c.