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5c1b662807
postgresql/contrib/pg_walinspect/pg_walinspect.c
Michael Paquier 5c1b662807 Rework design of functions in pg_walinspect 
This commit reworks a bit the set-returning functions of pg_walinspect,
making them more flexible regarding their end LSN:
- pg_get_wal_records_info()
- pg_get_wal_stats()
- pg_get_wal_block_info()

The end LSNs given to these functions is now handled so as a value
higher than the current LSN of the cluster (insert LSN for a primary, or
replay LSN for a standby) does not raise an error, giving more
flexibility to monitoring queries.  Instead, the functions return
results up to the current LSN, as found at the beginning of each
function call.

As an effect of that, pg_get_wal_records_info_till_end_of_wal() and
pg_get_wal_stats_till_end_of_wal() are now removed from 1.1, as the
existing, equivalent functions are able to offer the same
possibilities.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACU0_q-o4DSweyaW9NO1KBx-QkN6G_OzYQvpjf3CZVASkg@mail.gmail.com
2023-03-14 20:13:02 +09:00

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/*-------------------------------------------------------------------------
*
* pg_walinspect.c
* Functions to inspect contents of PostgreSQL Write-Ahead Log
*
* Copyright (c) 2022-2023, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/pg_walinspect/pg_walinspect.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "access/xlogreader.h"
#include "access/xlogrecovery.h"
#include "access/xlogstats.h"
#include "access/xlogutils.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
/*
* NOTE: For any code change or issue fix here, it is highly recommended to
* give a thought about doing the same in pg_waldump tool as well.
*/
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(pg_get_wal_block_info);
PG_FUNCTION_INFO_V1(pg_get_wal_record_info);
PG_FUNCTION_INFO_V1(pg_get_wal_records_info);
PG_FUNCTION_INFO_V1(pg_get_wal_records_info_till_end_of_wal);
PG_FUNCTION_INFO_V1(pg_get_wal_stats);
PG_FUNCTION_INFO_V1(pg_get_wal_stats_till_end_of_wal);
static void ValidateInputLSNs(XLogRecPtr start_lsn, XLogRecPtr *end_lsn);
static XLogRecPtr GetCurrentLSN(void);
static XLogReaderState *InitXLogReaderState(XLogRecPtr lsn);
static XLogRecord *ReadNextXLogRecord(XLogReaderState *xlogreader);
static void GetWALRecordInfo(XLogReaderState *record, Datum *values,
bool *nulls, uint32 ncols);
static void GetWALRecordsInfo(FunctionCallInfo fcinfo,
XLogRecPtr start_lsn,
XLogRecPtr end_lsn);
static void GetXLogSummaryStats(XLogStats *stats, ReturnSetInfo *rsinfo,
Datum *values, bool *nulls, uint32 ncols,
bool stats_per_record);
static void FillXLogStatsRow(const char *name, uint64 n, uint64 total_count,
uint64 rec_len, uint64 total_rec_len,
uint64 fpi_len, uint64 total_fpi_len,
uint64 tot_len, uint64 total_len,
Datum *values, bool *nulls, uint32 ncols);
static void GetWalStats(FunctionCallInfo fcinfo,
XLogRecPtr start_lsn,
XLogRecPtr end_lsn,
bool stats_per_record);
static void GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record);
/*
* Return the LSN up to which the server has WAL.
*/
static XLogRecPtr
GetCurrentLSN(void)
{
XLogRecPtr curr_lsn;
/*
* We determine the current LSN of the server similar to how page_read
* callback read_local_xlog_page_no_wait does.
*/
if (!RecoveryInProgress())
curr_lsn = GetFlushRecPtr(NULL);
else
curr_lsn = GetXLogReplayRecPtr(NULL);
Assert(!XLogRecPtrIsInvalid(curr_lsn));
return curr_lsn;
}
/*
* Intialize WAL reader and identify first valid LSN.
*/
static XLogReaderState *
InitXLogReaderState(XLogRecPtr lsn)
{
XLogReaderState *xlogreader;
ReadLocalXLogPageNoWaitPrivate *private_data;
XLogRecPtr first_valid_record;
/*
* Reading WAL below the first page of the first segments isn't allowed.
* This is a bootstrap WAL page and the page_read callback fails to read
* it.
*/
if (lsn < XLOG_BLCKSZ)
ereport(ERROR,
(errmsg("could not read WAL at LSN %X/%X",
LSN_FORMAT_ARGS(lsn))));
private_data = (ReadLocalXLogPageNoWaitPrivate *)
palloc0(sizeof(ReadLocalXLogPageNoWaitPrivate));
xlogreader = XLogReaderAllocate(wal_segment_size, NULL,
XL_ROUTINE(.page_read = &read_local_xlog_page_no_wait,
.segment_open = &wal_segment_open,
.segment_close = &wal_segment_close),
private_data);
if (xlogreader == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed while allocating a WAL reading processor.")));
/* first find a valid recptr to start from */
first_valid_record = XLogFindNextRecord(xlogreader, lsn);
if (XLogRecPtrIsInvalid(first_valid_record))
ereport(ERROR,
(errmsg("could not find a valid record after %X/%X",
LSN_FORMAT_ARGS(lsn))));
return xlogreader;
}
/*
* Read next WAL record.
*
* By design, to be less intrusive in a running system, no slot is allocated
* to reserve the WAL we're about to read. Therefore this function can
* encounter read errors for historical WAL.
*
* We guard against ordinary errors trying to read WAL that hasn't been
* written yet by limiting end_lsn to the flushed WAL, but that can also
* encounter errors if the flush pointer falls in the middle of a record. In
* that case we'll return NULL.
*/
static XLogRecord *
ReadNextXLogRecord(XLogReaderState *xlogreader)
{
XLogRecord *record;
char *errormsg;
record = XLogReadRecord(xlogreader, &errormsg);
if (record == NULL)
{
ReadLocalXLogPageNoWaitPrivate *private_data;
/* return NULL, if end of WAL is reached */
private_data = (ReadLocalXLogPageNoWaitPrivate *)
xlogreader->private_data;
if (private_data->end_of_wal)
return NULL;
if (errormsg)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read WAL at %X/%X: %s",
LSN_FORMAT_ARGS(xlogreader->EndRecPtr), errormsg)));
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read WAL at %X/%X",
LSN_FORMAT_ARGS(xlogreader->EndRecPtr))));
}
return record;
}
/*
* Get a single WAL record info.
*/
static void
GetWALRecordInfo(XLogReaderState *record, Datum *values,
bool *nulls, uint32 ncols)
{
const char *id;
RmgrData desc;
uint32 fpi_len = 0;
StringInfoData rec_desc;
StringInfoData rec_blk_ref;
uint32 main_data_len;
int i = 0;
desc = GetRmgr(XLogRecGetRmid(record));
id = desc.rm_identify(XLogRecGetInfo(record));
if (id == NULL)
id = psprintf("UNKNOWN (%x)", XLogRecGetInfo(record) & ~XLR_INFO_MASK);
initStringInfo(&rec_desc);
desc.rm_desc(&rec_desc, record);
/* Block references. */
initStringInfo(&rec_blk_ref);
XLogRecGetBlockRefInfo(record, false, true, &rec_blk_ref, &fpi_len);
main_data_len = XLogRecGetDataLen(record);
values[i++] = LSNGetDatum(record->ReadRecPtr);
values[i++] = LSNGetDatum(record->EndRecPtr);
values[i++] = LSNGetDatum(XLogRecGetPrev(record));
values[i++] = TransactionIdGetDatum(XLogRecGetXid(record));
values[i++] = CStringGetTextDatum(desc.rm_name);
values[i++] = CStringGetTextDatum(id);
values[i++] = UInt32GetDatum(XLogRecGetTotalLen(record));
values[i++] = UInt32GetDatum(main_data_len);
values[i++] = UInt32GetDatum(fpi_len);
values[i++] = CStringGetTextDatum(rec_desc.data);
values[i++] = CStringGetTextDatum(rec_blk_ref.data);
Assert(i == ncols);
}
/*
* Store a set of block information from a single record (FPI and block
* information).
*/
static void
GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record)
{
#define PG_GET_WAL_BLOCK_INFO_COLS 11
int block_id;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
{
DecodedBkpBlock *blk;
BlockNumber blkno;
RelFileLocator rnode;
ForkNumber fork;
Datum values[PG_GET_WAL_BLOCK_INFO_COLS] = {0};
bool nulls[PG_GET_WAL_BLOCK_INFO_COLS] = {0};
int i = 0;
if (!XLogRecHasBlockRef(record, block_id))
continue;
blk = XLogRecGetBlock(record, block_id);
(void) XLogRecGetBlockTagExtended(record, block_id,
&rnode, &fork, &blkno, NULL);
values[i++] = LSNGetDatum(record->ReadRecPtr);
values[i++] = Int16GetDatum(block_id);
values[i++] = ObjectIdGetDatum(blk->rlocator.spcOid);
values[i++] = ObjectIdGetDatum(blk->rlocator.dbOid);
values[i++] = ObjectIdGetDatum(blk->rlocator.relNumber);
values[i++] = Int64GetDatum((int64) blkno);
if (fork >= 0 && fork <= MAX_FORKNUM)
values[i++] = CStringGetTextDatum(forkNames[fork]);
else
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg_internal("invalid fork number: %u", fork)));
/* Block data */
if (blk->has_data)
{
bytea *raw_data;
/* Initialize bytea buffer to copy the data to */
raw_data = (bytea *) palloc(blk->data_len + VARHDRSZ);
SET_VARSIZE(raw_data, blk->data_len + VARHDRSZ);
/* Copy the data */
memcpy(VARDATA(raw_data), blk->data, blk->data_len);
values[i++] = PointerGetDatum(raw_data);
}
else
{
/* No data, so set this field to NULL */
nulls[i++] = true;
}
if (blk->has_image)
{
PGAlignedBlock buf;
Page page;
bytea *raw_page;
int bitcnt;
int cnt = 0;
Datum *flags;
ArrayType *a;
page = (Page) buf.data;
/* Full page image exists, so let's save it */
if (!RestoreBlockImage(record, block_id, page))
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg_internal("%s", record->errormsg_buf)));
/* Initialize bytea buffer to copy the FPI to */
raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
/* Take a verbatim copy of the FPI */
memcpy(VARDATA(raw_page), page, BLCKSZ);
values[i++] = PointerGetDatum(raw_page);
values[i++] = UInt32GetDatum(blk->bimg_len);
/* FPI flags */
bitcnt = pg_popcount((const char *) &blk->bimg_info,
sizeof(uint8));
/* Build set of raw flags */
flags = (Datum *) palloc0(sizeof(Datum) * bitcnt);
if ((blk->bimg_info & BKPIMAGE_HAS_HOLE) != 0)
flags[cnt++] = CStringGetTextDatum("HAS_HOLE");
if (blk->apply_image)
flags[cnt++] = CStringGetTextDatum("APPLY");
if ((blk->bimg_info & BKPIMAGE_COMPRESS_PGLZ) != 0)
flags[cnt++] = CStringGetTextDatum("COMPRESS_PGLZ");
if ((blk->bimg_info & BKPIMAGE_COMPRESS_LZ4) != 0)
flags[cnt++] = CStringGetTextDatum("COMPRESS_LZ4");
if ((blk->bimg_info & BKPIMAGE_COMPRESS_ZSTD) != 0)
flags[cnt++] = CStringGetTextDatum("COMPRESS_ZSTD");
Assert(cnt <= bitcnt);
a = construct_array_builtin(flags, cnt, TEXTOID);
values[i++] = PointerGetDatum(a);
}
else
{
/* No full page image, so store NULLs for all its fields */
memset(&nulls[i], true, 3 * sizeof(bool));
i += 3;
}
Assert(i == PG_GET_WAL_BLOCK_INFO_COLS);
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
values, nulls);
}
#undef PG_GET_WAL_FPI_BLOCK_COLS
}
/*
* Get information about all the blocks saved in WAL records between start
* and end LSNs. This produces information about the full page images with
* their relation information, and the data saved in each block associated
* to a record. Decompression is applied to the full page images, if
* necessary.
*/
Datum
pg_get_wal_block_info(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = PG_GETARG_LSN(1);
XLogReaderState *xlogreader;
MemoryContext old_cxt;
MemoryContext tmp_cxt;
ValidateInputLSNs(start_lsn, &end_lsn);
InitMaterializedSRF(fcinfo, 0);
xlogreader = InitXLogReaderState(start_lsn);
tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
"pg_get_block_fpi_info temporary cxt",
ALLOCSET_DEFAULT_SIZES);
while (ReadNextXLogRecord(xlogreader) &&
xlogreader->EndRecPtr <= end_lsn)
{
/* Use the tmp context so we can clean up after each tuple is done */
old_cxt = MemoryContextSwitchTo(tmp_cxt);
GetWALBlockInfo(fcinfo, xlogreader);
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);
MemoryContextReset(tmp_cxt);
CHECK_FOR_INTERRUPTS();
}
MemoryContextDelete(tmp_cxt);
pfree(xlogreader->private_data);
XLogReaderFree(xlogreader);
PG_RETURN_VOID();
}
/*
* Get WAL record info.
*/
Datum
pg_get_wal_record_info(PG_FUNCTION_ARGS)
{
#define PG_GET_WAL_RECORD_INFO_COLS 11
Datum result;
Datum values[PG_GET_WAL_RECORD_INFO_COLS] = {0};
bool nulls[PG_GET_WAL_RECORD_INFO_COLS] = {0};
XLogRecPtr lsn;
XLogRecPtr curr_lsn;
XLogReaderState *xlogreader;
TupleDesc tupdesc;
HeapTuple tuple;
lsn = PG_GETARG_LSN(0);
curr_lsn = GetCurrentLSN();
if (lsn > curr_lsn)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("WAL input LSN must be less than current LSN"),
errdetail("Current WAL LSN on the database system is at %X/%X.",
LSN_FORMAT_ARGS(curr_lsn))));
/* Build a tuple descriptor for our result type. */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
xlogreader = InitXLogReaderState(lsn);
if (!ReadNextXLogRecord(xlogreader))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not read WAL at %X/%X",
LSN_FORMAT_ARGS(xlogreader->EndRecPtr))));
GetWALRecordInfo(xlogreader, values, nulls, PG_GET_WAL_RECORD_INFO_COLS);
pfree(xlogreader->private_data);
XLogReaderFree(xlogreader);
tuple = heap_form_tuple(tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
PG_RETURN_DATUM(result);
#undef PG_GET_WAL_RECORD_INFO_COLS
}
/*
* Validate start and end LSNs coming from the function inputs.
*
* If end_lsn is found to be higher than the current LSN reported by the
* cluster, use the current LSN as the upper bound.
*/
static void
ValidateInputLSNs(XLogRecPtr start_lsn, XLogRecPtr *end_lsn)
{
XLogRecPtr curr_lsn = GetCurrentLSN();
if (start_lsn > curr_lsn)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("WAL start LSN must be less than current LSN"),
errdetail("Current WAL LSN on the database system is at %X/%X.",
LSN_FORMAT_ARGS(curr_lsn))));
if (start_lsn > *end_lsn)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("WAL start LSN must be less than end LSN")));
if (*end_lsn > curr_lsn)
*end_lsn = curr_lsn;
}
/*
* Get info and data of all WAL records between start LSN and end LSN.
*/
static void
GetWALRecordsInfo(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
XLogRecPtr end_lsn)
{
#define PG_GET_WAL_RECORDS_INFO_COLS 11
XLogReaderState *xlogreader;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
Datum values[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
bool nulls[PG_GET_WAL_RECORDS_INFO_COLS] = {0};
MemoryContext old_cxt;
MemoryContext tmp_cxt;
Assert(start_lsn <= end_lsn);
InitMaterializedSRF(fcinfo, 0);
xlogreader = InitXLogReaderState(start_lsn);
tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
"GetWALRecordsInfo temporary cxt",
ALLOCSET_DEFAULT_SIZES);
while (ReadNextXLogRecord(xlogreader) &&
xlogreader->EndRecPtr <= end_lsn)
{
/* Use the tmp context so we can clean up after each tuple is done */
old_cxt = MemoryContextSwitchTo(tmp_cxt);
GetWALRecordInfo(xlogreader, values, nulls,
PG_GET_WAL_RECORDS_INFO_COLS);
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
values, nulls);
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);
MemoryContextReset(tmp_cxt);
CHECK_FOR_INTERRUPTS();
}
MemoryContextDelete(tmp_cxt);
pfree(xlogreader->private_data);
XLogReaderFree(xlogreader);
#undef PG_GET_WAL_RECORDS_INFO_COLS
}
/*
* Get info and data of all WAL records between start LSN and end LSN.
*/
Datum
pg_get_wal_records_info(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = PG_GETARG_LSN(1);
ValidateInputLSNs(start_lsn, &end_lsn);
GetWALRecordsInfo(fcinfo, start_lsn, end_lsn);
PG_RETURN_VOID();
}
/*
* Fill single row of record counts and sizes for an rmgr or record.
*/
static void
FillXLogStatsRow(const char *name,
uint64 n, uint64 total_count,
uint64 rec_len, uint64 total_rec_len,
uint64 fpi_len, uint64 total_fpi_len,
uint64 tot_len, uint64 total_len,
Datum *values, bool *nulls, uint32 ncols)
{
double n_pct,
rec_len_pct,
fpi_len_pct,
tot_len_pct;
int i = 0;
n_pct = 0;
if (total_count != 0)
n_pct = 100 * (double) n / total_count;
rec_len_pct = 0;
if (total_rec_len != 0)
rec_len_pct = 100 * (double) rec_len / total_rec_len;
fpi_len_pct = 0;
if (total_fpi_len != 0)
fpi_len_pct = 100 * (double) fpi_len / total_fpi_len;
tot_len_pct = 0;
if (total_len != 0)
tot_len_pct = 100 * (double) tot_len / total_len;
values[i++] = CStringGetTextDatum(name);
values[i++] = Int64GetDatum(n);
values[i++] = Float8GetDatum(n_pct);
values[i++] = Int64GetDatum(rec_len);
values[i++] = Float8GetDatum(rec_len_pct);
values[i++] = Int64GetDatum(fpi_len);
values[i++] = Float8GetDatum(fpi_len_pct);
values[i++] = Int64GetDatum(tot_len);
values[i++] = Float8GetDatum(tot_len_pct);
Assert(i == ncols);
}
/*
* Get summary statistics about the records seen so far.
*/
static void
GetXLogSummaryStats(XLogStats *stats, ReturnSetInfo *rsinfo,
Datum *values, bool *nulls, uint32 ncols,
bool stats_per_record)
{
MemoryContext old_cxt;
MemoryContext tmp_cxt;
uint64 total_count = 0;
uint64 total_rec_len = 0;
uint64 total_fpi_len = 0;
uint64 total_len = 0;
int ri;
/*
* Each row shows its percentages of the total, so make a first pass to
* calculate column totals.
*/
for (ri = 0; ri <= RM_MAX_ID; ri++)
{
if (!RmgrIdIsValid(ri))
continue;
total_count += stats->rmgr_stats[ri].count;
total_rec_len += stats->rmgr_stats[ri].rec_len;
total_fpi_len += stats->rmgr_stats[ri].fpi_len;
}
total_len = total_rec_len + total_fpi_len;
tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
"GetXLogSummaryStats temporary cxt",
ALLOCSET_DEFAULT_SIZES);
for (ri = 0; ri <= RM_MAX_ID; ri++)
{
uint64 count;
uint64 rec_len;
uint64 fpi_len;
uint64 tot_len;
RmgrData desc;
if (!RmgrIdIsValid(ri))
continue;
if (!RmgrIdExists(ri))
continue;
desc = GetRmgr(ri);
if (stats_per_record)
{
int rj;
for (rj = 0; rj < MAX_XLINFO_TYPES; rj++)
{
const char *id;
count = stats->record_stats[ri][rj].count;
rec_len = stats->record_stats[ri][rj].rec_len;
fpi_len = stats->record_stats[ri][rj].fpi_len;
tot_len = rec_len + fpi_len;
/* Skip undefined combinations and ones that didn't occur */
if (count == 0)
continue;
old_cxt = MemoryContextSwitchTo(tmp_cxt);
/* the upper four bits in xl_info are the rmgr's */
id = desc.rm_identify(rj << 4);
if (id == NULL)
id = psprintf("UNKNOWN (%x)", rj << 4);
FillXLogStatsRow(psprintf("%s/%s", desc.rm_name, id), count,
total_count, rec_len, total_rec_len, fpi_len,
total_fpi_len, tot_len, total_len,
values, nulls, ncols);
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
values, nulls);
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);
MemoryContextReset(tmp_cxt);
}
}
else
{
count = stats->rmgr_stats[ri].count;
rec_len = stats->rmgr_stats[ri].rec_len;
fpi_len = stats->rmgr_stats[ri].fpi_len;
tot_len = rec_len + fpi_len;
old_cxt = MemoryContextSwitchTo(tmp_cxt);
FillXLogStatsRow(desc.rm_name, count, total_count, rec_len,
total_rec_len, fpi_len, total_fpi_len, tot_len,
total_len, values, nulls, ncols);
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
values, nulls);
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);
MemoryContextReset(tmp_cxt);
}
}
MemoryContextDelete(tmp_cxt);
}
/*
* Get WAL stats between start LSN and end LSN.
*/
static void
GetWalStats(FunctionCallInfo fcinfo, XLogRecPtr start_lsn, XLogRecPtr end_lsn,
bool stats_per_record)
{
#define PG_GET_WAL_STATS_COLS 9
XLogReaderState *xlogreader;
XLogStats stats = {0};
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
Datum values[PG_GET_WAL_STATS_COLS] = {0};
bool nulls[PG_GET_WAL_STATS_COLS] = {0};
Assert(start_lsn <= end_lsn);
InitMaterializedSRF(fcinfo, 0);
xlogreader = InitXLogReaderState(start_lsn);
while (ReadNextXLogRecord(xlogreader) &&
xlogreader->EndRecPtr <= end_lsn)
{
XLogRecStoreStats(&stats, xlogreader);
CHECK_FOR_INTERRUPTS();
}
pfree(xlogreader->private_data);
XLogReaderFree(xlogreader);
GetXLogSummaryStats(&stats, rsinfo, values, nulls,
PG_GET_WAL_STATS_COLS,
stats_per_record);
#undef PG_GET_WAL_STATS_COLS
}
/*
* Get stats of all WAL records between start LSN and end LSN.
*/
Datum
pg_get_wal_stats(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = PG_GETARG_LSN(1);
bool stats_per_record = PG_GETARG_BOOL(2);
ValidateInputLSNs(start_lsn, &end_lsn);
GetWalStats(fcinfo, start_lsn, end_lsn, stats_per_record);
PG_RETURN_VOID();
}
/*
* The following functions have been removed in newer versions in 1.1, but
* they are kept around for compatibility.
*/
Datum
pg_get_wal_records_info_till_end_of_wal(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = GetCurrentLSN();
if (start_lsn > end_lsn)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("WAL start LSN must be less than current LSN"),
errdetail("Current WAL LSN on the database system is at %X/%X.",
LSN_FORMAT_ARGS(end_lsn))));
GetWALRecordsInfo(fcinfo, start_lsn, end_lsn);
PG_RETURN_VOID();
}
Datum
pg_get_wal_stats_till_end_of_wal(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = GetCurrentLSN();
bool stats_per_record = PG_GETARG_BOOL(1);
if (start_lsn > end_lsn)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("WAL start LSN must be less than current LSN"),
errdetail("Current WAL LSN on the database system is at %X/%X.",
LSN_FORMAT_ARGS(end_lsn))));
GetWalStats(fcinfo, start_lsn, end_lsn, stats_per_record);
PG_RETURN_VOID();
}
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