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authorPeter Geoghegan2023-03-31 21:02:52 +0000
committerPeter Geoghegan2023-03-31 21:02:52 +0000
commitdf4f3ab51730a4cdddfead0b264d394ee4925723 (patch)
tree95b086f2a6e89b192555dd1bb1408f3225d45ae5 /contrib/pg_walinspect/pg_walinspect.c
parent6ee30209a6f161d0a267a33f090c70c579c87c00 (diff)
Add show_data option to pg_get_wal_block_info.
Allow users to opt out of returning FPI data and block data from pg_get_wal_block_info as an optimization. Testing has shown that this can make function execution over twice as fast in some cases. When pg_get_wal_block_info is called with "show_data := false", it always returns NULL values for its block_data and block_fpi_data bytea output parameters. Nothing else changes. In particular, the function will still return the usual per-block summary of block data/FPI space overhead. Use of "show_data := false" is therefore feasible with all queries that don't specifically require these raw binary strings. Follow-up to recent work in commit 122376f0. There still hasn't been a stable release with the pg_get_wal_block_info function, so no bump in the pg_walinspect extension version. Per suggestion from Melanie Plageman. Author: Peter Geoghegan <[email protected]> Discussion: https://postgr.es/m/CAAKRu_bJvbcYBRj2cN6G2xV7B7-Ja+pjTO1nEnEhRR8OXYiABA@mail.gmail.com Discussion: https://postgr.es/m/CAH2-Wzm9shOkEDM10_+qOZkRSQhKVxwBFiehH6EHWQQRd_rDPw@mail.gmail.com
Diffstat (limited to 'contrib/pg_walinspect/pg_walinspect.c')
-rw-r--r--contrib/pg_walinspect/pg_walinspect.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/contrib/pg_walinspect/pg_walinspect.c b/contrib/pg_walinspect/pg_walinspect.c
index 1ff53c5abcc..e4dbf15e05d 100644
--- a/contrib/pg_walinspect/pg_walinspect.c
+++ b/contrib/pg_walinspect/pg_walinspect.c
@@ -59,7 +59,8 @@ static void GetWalStats(FunctionCallInfo fcinfo,
XLogRecPtr start_lsn,
XLogRecPtr end_lsn,
bool stats_per_record);
-static void GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record);
+static void GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record,
+ bool show_data);
/*
* Return the LSN up to which the server has WAL.
@@ -244,7 +245,8 @@ GetWALRecordInfo(XLogReaderState *record, Datum *values,
* Keep this in sync with GetWALRecordInfo.
*/
static void
-GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record)
+GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record,
+ bool show_data)
{
#define PG_GET_WAL_BLOCK_INFO_COLS 20
int block_id;
@@ -359,7 +361,7 @@ GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record)
nulls[i++] = true;
/* block_data output */
- if (blk->has_data)
+ if (blk->has_data && show_data)
{
bytea *block_data;
@@ -372,7 +374,7 @@ GetWALBlockInfo(FunctionCallInfo fcinfo, XLogReaderState *record)
nulls[i++] = true;
/* block_fpi_data output */
- if (blk->has_image)
+ if (blk->has_image && show_data)
{
PGAlignedBlock buf;
Page page;
@@ -410,6 +412,7 @@ pg_get_wal_block_info(PG_FUNCTION_ARGS)
{
XLogRecPtr start_lsn = PG_GETARG_LSN(0);
XLogRecPtr end_lsn = PG_GETARG_LSN(1);
+ bool show_data = PG_GETARG_BOOL(2);
XLogReaderState *xlogreader;
MemoryContext old_cxt;
MemoryContext tmp_cxt;
@@ -435,7 +438,7 @@ pg_get_wal_block_info(PG_FUNCTION_ARGS)
/* Use the tmp context so we can clean up after each tuple is done */
old_cxt = MemoryContextSwitchTo(tmp_cxt);
- GetWALBlockInfo(fcinfo, xlogreader);
+ GetWALBlockInfo(fcinfo, xlogreader, show_data);
/* clean up and switch back */
MemoryContextSwitchTo(old_cxt);