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| author | Amit Kapila <akapila@postgresql.org> | 2020-04-04 10:02:08 +0530 |
|---|---|---|
| committer | Amit Kapila <akapila@postgresql.org> | 2020-04-04 10:02:08 +0530 |
| commit | df3b181499b40523bd6244a4e5eb554acb9020ce (patch) | |
| tree | 520cb5eee0f4c1404face0b9df8be2c68158a7d2 /src/backend/access/transam/xloginsert.c | |
| parent | 0588ee63aa2d8c5765d086991555cd9acdd4d86f (diff) | |
| download | postgresql-df3b181499b40523bd6244a4e5eb554acb9020ce.tar.gz postgresql-df3b181499b40523bd6244a4e5eb554acb9020ce.zip | |
Add infrastructure to track WAL usage.
This allows gathering the WAL generation statistics for each statement
execution. The three statistics that we collect are the number of WAL
records, the number of full page writes and the amount of WAL bytes
generated.
This helps the users who have write-intensive workload to see the impact
of I/O due to WAL. This further enables us to see approximately what
percentage of overall WAL is due to full page writes.
In the future, we can extend this functionality to allow us to compute the
the exact amount of WAL data due to full page writes.
This patch in itself is just an infrastructure to compute WAL usage data.
The upcoming patches will expose this data via explain, auto_explain,
pg_stat_statements and verbose (auto)vacuum output.
Author: Kirill Bychik, Julien Rouhaud
Reviewed-by: Dilip Kumar, Fujii Masao and Amit Kapila
Discussion: https://postgr.es/m/CAB-hujrP8ZfUkvL5OYETipQwA=e3n7oqHFU=4ZLxWS_Cza3kQQ@mail.gmail.com
Diffstat (limited to 'src/backend/access/transam/xloginsert.c')
| -rw-r--r-- | src/backend/access/transam/xloginsert.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c index a618dec776c..5e032e7042d 100644 --- a/src/backend/access/transam/xloginsert.c +++ b/src/backend/access/transam/xloginsert.c @@ -25,6 +25,7 @@ #include "access/xloginsert.h" #include "catalog/pg_control.h" #include "common/pg_lzcompress.h" +#include "executor/instrument.h" #include "miscadmin.h" #include "pg_trace.h" #include "replication/origin.h" @@ -108,7 +109,7 @@ static MemoryContext xloginsert_cxt; static XLogRecData *XLogRecordAssemble(RmgrId rmid, uint8 info, XLogRecPtr RedoRecPtr, bool doPageWrites, - XLogRecPtr *fpw_lsn); + XLogRecPtr *fpw_lsn, int *num_fpw); static bool XLogCompressBackupBlock(char *page, uint16 hole_offset, uint16 hole_length, char *dest, uint16 *dlen); @@ -448,6 +449,7 @@ XLogInsert(RmgrId rmid, uint8 info) bool doPageWrites; XLogRecPtr fpw_lsn; XLogRecData *rdt; + int num_fpw = 0; /* * Get values needed to decide whether to do full-page writes. Since @@ -457,9 +459,9 @@ XLogInsert(RmgrId rmid, uint8 info) GetFullPageWriteInfo(&RedoRecPtr, &doPageWrites); rdt = XLogRecordAssemble(rmid, info, RedoRecPtr, doPageWrites, - &fpw_lsn); + &fpw_lsn, &num_fpw); - EndPos = XLogInsertRecord(rdt, fpw_lsn, curinsert_flags); + EndPos = XLogInsertRecord(rdt, fpw_lsn, curinsert_flags, num_fpw); } while (EndPos == InvalidXLogRecPtr); XLogResetInsertion(); @@ -482,7 +484,7 @@ XLogInsert(RmgrId rmid, uint8 info) static XLogRecData * XLogRecordAssemble(RmgrId rmid, uint8 info, XLogRecPtr RedoRecPtr, bool doPageWrites, - XLogRecPtr *fpw_lsn) + XLogRecPtr *fpw_lsn, int *num_fpw) { XLogRecData *rdt; uint32 total_len = 0; @@ -635,6 +637,9 @@ XLogRecordAssemble(RmgrId rmid, uint8 info, */ bkpb.fork_flags |= BKPBLOCK_HAS_IMAGE; + /* Report a full page image constructed for the WAL record */ + *num_fpw += 1; + /* * Construct XLogRecData entries for the page content. */ |