rdelaage/postgresql
1
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-09-28 21:01:48 +02:00
Code Issues Packages Projects Releases Wiki Activity

Reduce size of two phase file header

Browse Source 
Previously 2PC header was fixed at 200 bytes, which in most cases wasted
WAL space for a workload using 2PC heavily.

Pavan Deolasee, reviewed by Petr Jelinek
This commit is contained in:
Simon Riggs 2016-03-10 12:51:46 +00:00
parent fcb4bfddb6
commit e0694cf9c7
1 changed files with 12 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/access/transam/twophase.c
View File

@ -126,6 +126,9 @@ int max_prepared_xacts = 0;
*
* typedef struct GlobalTransactionData *GlobalTransaction appears in
* twophase.h
*
* Note that the max value of GIDSIZE must fit in the uint16 gidlen,
* specified in TwoPhaseFileHeader.
*/
#define GIDSIZE 200
@ -851,7 +854,7 @@ TwoPhaseGetDummyProc(TransactionId xid)
/*
* Header for a 2PC state file
*/
#define TWOPHASE_MAGIC 0x57F94532 /* format identifier */
#define TWOPHASE_MAGIC 0x57F94533 /* format identifier */
typedef struct TwoPhaseFileHeader
{
@ -866,7 +869,7 @@ typedef struct TwoPhaseFileHeader
int32 nabortrels; /* number of delete-on-abort rels */
int32 ninvalmsgs; /* number of cache invalidation messages */
bool initfileinval; /* does relcache init file need invalidation? */
char gid[GIDSIZE]; /* GID for transaction */
uint16 gidlen; /* length of the GID - GID follows the header */
} TwoPhaseFileHeader;
/*
@ -977,9 +980,10 @@ StartPrepare(GlobalTransaction gxact)
hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
hdr.ninvalmsgs = xactGetCommittedInvalidationMessages(&invalmsgs,
&hdr.initfileinval);
StrNCpy(hdr.gid, gxact->gid, GIDSIZE);
hdr.gidlen = strlen(gxact->gid) + 1; /* Include '\0' */
save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
save_state_data(gxact->gid, hdr.gidlen);
/*
* Add the additional info about subxacts, deletable files and cache
@ -1360,6 +1364,7 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
hdr = (TwoPhaseFileHeader *) buf;
Assert(TransactionIdEquals(hdr->xid, xid));
bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
bufptr += MAXALIGN(hdr->gidlen);
children = (TransactionId *) bufptr;
bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
commitrels = (RelFileNode *) bufptr;
@ -1915,6 +1920,7 @@ RecoverPreparedTransactions(void)
TwoPhaseFileHeader *hdr;
TransactionId *subxids;
GlobalTransaction gxact;
const char *gid;
int i;
xid = (TransactionId) strtoul(clde->d_name, NULL, 16);
@ -1947,6 +1953,8 @@ RecoverPreparedTransactions(void)
hdr = (TwoPhaseFileHeader *) buf;
Assert(TransactionIdEquals(hdr->xid, xid));
bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
gid = (const char *) bufptr;
bufptr += MAXALIGN(hdr->gidlen);
subxids = (TransactionId *) bufptr;
bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
@ -1975,7 +1983,7 @@ RecoverPreparedTransactions(void)
/*
* Recreate its GXACT and dummy PGPROC
*/
gxact = MarkAsPreparing(xid, hdr->gid,
gxact = MarkAsPreparing(xid, gid,
hdr->prepared_at,
hdr->owner, hdr->database);
gxact->ondisk = true;