pg_controldata.c

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/*-------------------------------------------------------------------------
 *
 * pg_controldata.c
 *
 * Routines to expose the contents of the control data file via
 * a set of SQL functions.
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/utils/misc/pg_controldata.c
 *-------------------------------------------------------------------------
 */
 
#include "postgres.h"
 
#include "access/htup_details.h"
#include "access/transam.h"
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "catalog/pg_control.h"
#include "common/controldata_utils.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/lwlock.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
#include "utils/timestamp.h"
 
Datum
pg_control_system(PG_FUNCTION_ARGS)
{
    Datum       values[4];
    bool        nulls[4];
    TupleDesc   tupdesc;
    HeapTuple   htup;
    ControlFileData *ControlFile;
    bool        crc_ok;
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* read the control file */
    LWLockAcquire(ControlFileLock, LW_SHARED);
    ControlFile = get_controlfile(DataDir, &crc_ok);
    LWLockRelease(ControlFileLock);
    if (!crc_ok)
        ereport(ERROR,
                (errmsg("calculated CRC checksum does not match value stored in file")));
 
    values[0] = Int32GetDatum(ControlFile->pg_control_version);
    nulls[0] = false;
 
    values[1] = Int32GetDatum(ControlFile->catalog_version_no);
    nulls[1] = false;
 
    values[2] = Int64GetDatum(ControlFile->system_identifier);
    nulls[2] = false;
 
    values[3] = TimestampTzGetDatum(time_t_to_timestamptz(ControlFile->time));
    nulls[3] = false;
 
    htup = heap_form_tuple(tupdesc, values, nulls);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(htup));
}
 
Datum
pg_control_checkpoint(PG_FUNCTION_ARGS)
{
    Datum       values[19];
    bool        nulls[19];
    TupleDesc   tupdesc;
    HeapTuple   htup;
    ControlFileData *ControlFile;
    XLogSegNo   segno;
    char        xlogfilename[MAXFNAMELEN];
    bool        crc_ok;
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* Read the control file. */
    LWLockAcquire(ControlFileLock, LW_SHARED);
    ControlFile = get_controlfile(DataDir, &crc_ok);
    LWLockRelease(ControlFileLock);
    if (!crc_ok)
        ereport(ERROR,
                (errmsg("calculated CRC checksum does not match value stored in file")));
 
    /*
     * Calculate name of the WAL file containing the latest checkpoint's REDO
     * start point.
     */
    XLByteToSeg(ControlFile->checkPointCopy.redo, segno, wal_segment_size);
    XLogFileName(xlogfilename, ControlFile->checkPointCopy.ThisTimeLineID,
                 segno, wal_segment_size);
 
    /* Populate the values and null arrays */
    values[0] = LSNGetDatum(ControlFile->checkPoint);
    nulls[0] = false;
 
    values[1] = LSNGetDatum(ControlFile->checkPointCopy.redo);
    nulls[1] = false;
 
    values[2] = CStringGetTextDatum(xlogfilename);
    nulls[2] = false;
 
    values[3] = Int32GetDatum(ControlFile->checkPointCopy.ThisTimeLineID);
    nulls[3] = false;
 
    values[4] = Int32GetDatum(ControlFile->checkPointCopy.PrevTimeLineID);
    nulls[4] = false;
 
    values[5] = BoolGetDatum(ControlFile->checkPointCopy.fullPageWrites);
    nulls[5] = false;
 
    values[6] = BoolGetDatum(ControlFile->checkPointCopy.logicalDecodingEnabled);
    nulls[6] = false;
 
    values[7] = CStringGetTextDatum(psprintf("%u:%u",
                                             EpochFromFullTransactionId(ControlFile->checkPointCopy.nextXid),
                                             XidFromFullTransactionId(ControlFile->checkPointCopy.nextXid)));
    nulls[7] = false;
 
    values[8] = ObjectIdGetDatum(ControlFile->checkPointCopy.nextOid);
    nulls[8] = false;
 
    values[9] = TransactionIdGetDatum(ControlFile->checkPointCopy.nextMulti);
    nulls[9] = false;
 
    values[10] = TransactionIdGetDatum(ControlFile->checkPointCopy.nextMultiOffset);
    nulls[10] = false;
 
    values[11] = TransactionIdGetDatum(ControlFile->checkPointCopy.oldestXid);
    nulls[11] = false;
 
    values[12] = ObjectIdGetDatum(ControlFile->checkPointCopy.oldestXidDB);
    nulls[12] = false;
 
    values[13] = TransactionIdGetDatum(ControlFile->checkPointCopy.oldestActiveXid);
    nulls[13] = false;
 
    values[14] = TransactionIdGetDatum(ControlFile->checkPointCopy.oldestMulti);
    nulls[14] = false;
 
    values[15] = ObjectIdGetDatum(ControlFile->checkPointCopy.oldestMultiDB);
    nulls[15] = false;
 
    values[16] = TransactionIdGetDatum(ControlFile->checkPointCopy.oldestCommitTsXid);
    nulls[16] = false;
 
    values[17] = TransactionIdGetDatum(ControlFile->checkPointCopy.newestCommitTsXid);
    nulls[17] = false;
 
    values[18] = TimestampTzGetDatum(time_t_to_timestamptz(ControlFile->checkPointCopy.time));
    nulls[18] = false;
 
    htup = heap_form_tuple(tupdesc, values, nulls);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(htup));
}
 
Datum
pg_control_recovery(PG_FUNCTION_ARGS)
{
    Datum       values[5];
    bool        nulls[5];
    TupleDesc   tupdesc;
    HeapTuple   htup;
    ControlFileData *ControlFile;
    bool        crc_ok;
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* read the control file */
    LWLockAcquire(ControlFileLock, LW_SHARED);
    ControlFile = get_controlfile(DataDir, &crc_ok);
    LWLockRelease(ControlFileLock);
    if (!crc_ok)
        ereport(ERROR,
                (errmsg("calculated CRC checksum does not match value stored in file")));
 
    values[0] = LSNGetDatum(ControlFile->minRecoveryPoint);
    nulls[0] = false;
 
    values[1] = Int32GetDatum(ControlFile->minRecoveryPointTLI);
    nulls[1] = false;
 
    values[2] = LSNGetDatum(ControlFile->backupStartPoint);
    nulls[2] = false;
 
    values[3] = LSNGetDatum(ControlFile->backupEndPoint);
    nulls[3] = false;
 
    values[4] = BoolGetDatum(ControlFile->backupEndRequired);
    nulls[4] = false;
 
    htup = heap_form_tuple(tupdesc, values, nulls);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(htup));
}
 
Datum
pg_control_init(PG_FUNCTION_ARGS)
{
    Datum       values[12];
    bool        nulls[12];
    TupleDesc   tupdesc;
    HeapTuple   htup;
    ControlFileData *ControlFile;
    bool        crc_ok;
 
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* read the control file */
    LWLockAcquire(ControlFileLock, LW_SHARED);
    ControlFile = get_controlfile(DataDir, &crc_ok);
    LWLockRelease(ControlFileLock);
    if (!crc_ok)
        ereport(ERROR,
                (errmsg("calculated CRC checksum does not match value stored in file")));
 
    values[0] = Int32GetDatum(ControlFile->maxAlign);
    nulls[0] = false;
 
    values[1] = Int32GetDatum(ControlFile->blcksz);
    nulls[1] = false;
 
    values[2] = Int32GetDatum(ControlFile->relseg_size);
    nulls[2] = false;
 
    values[3] = Int32GetDatum(ControlFile->xlog_blcksz);
    nulls[3] = false;
 
    values[4] = Int32GetDatum(ControlFile->xlog_seg_size);
    nulls[4] = false;
 
    values[5] = Int32GetDatum(ControlFile->nameDataLen);
    nulls[5] = false;
 
    values[6] = Int32GetDatum(ControlFile->indexMaxKeys);
    nulls[6] = false;
 
    values[7] = Int32GetDatum(ControlFile->toast_max_chunk_size);
    nulls[7] = false;
 
    values[8] = Int32GetDatum(ControlFile->loblksize);
    nulls[8] = false;
 
    values[9] = BoolGetDatum(ControlFile->float8ByVal);
    nulls[9] = false;
 
    values[10] = Int32GetDatum(ControlFile->data_checksum_version);
    nulls[10] = false;
 
    values[11] = BoolGetDatum(ControlFile->default_char_signedness);
    nulls[11] = false;
 
    htup = heap_form_tuple(tupdesc, values, nulls);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(htup));
}