diff options
| author | Robert Haas | 2017-03-23 18:08:23 +0000 |
|---|---|---|
| committer | Robert Haas | 2017-03-23 18:26:31 +0000 |
| commit | ea42cc18c35381f639d45628d792e790ff39e271 (patch) | |
| tree | 223916f28189cb8fb5b40793ff563928795f62ca /src/include | |
| parent | 50c956add83963d7bbb367dd0b879fccddebd623 (diff) | |
Track the oldest XID that can be safely looked up in CLOG.
This provides infrastructure for looking up arbitrary, user-supplied
XIDs without a risk of scary-looking failures from within the clog
module. Normally, the oldest XID that can be safely looked up in CLOG
is the same as the oldest XID that can reused without causing
wraparound, and the latter is already tracked. However, while
truncation is in progress, the values are different, so we must
keep track of them separately.
Craig Ringer, reviewed by Simon Riggs and by me.
Discussion: http://postgr.es/m/CAMsr+YHQiWNEi0daCTboS40T+V5s_+dst3PYv_8v2wNVH+Xx4g@mail.gmail.com
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/access/clog.h | 8 | ||||
| -rw-r--r-- | src/include/access/transam.h | 7 | ||||
| -rw-r--r-- | src/include/access/xlog_internal.h | 2 |
3 files changed, 15 insertions, 2 deletions
diff --git a/src/include/access/clog.h b/src/include/access/clog.h index 2894bd5620b..60a9e11a0fa 100644 --- a/src/include/access/clog.h +++ b/src/include/access/clog.h @@ -28,6 +28,12 @@ typedef int XidStatus; #define TRANSACTION_STATUS_ABORTED 0x02 #define TRANSACTION_STATUS_SUB_COMMITTED 0x03 +typedef struct xl_clog_truncate +{ + int pageno; + TransactionId oldestXact; + Oid oldestXactDb; +} xl_clog_truncate; extern void TransactionIdSetTreeStatus(TransactionId xid, int nsubxids, TransactionId *subxids, XidStatus status, XLogRecPtr lsn); @@ -42,7 +48,7 @@ extern void TrimCLOG(void); extern void ShutdownCLOG(void); extern void CheckPointCLOG(void); extern void ExtendCLOG(TransactionId newestXact); -extern void TruncateCLOG(TransactionId oldestXact); +extern void TruncateCLOG(TransactionId oldestXact, Oid oldestxid_datoid); /* XLOG stuff */ #define CLOG_ZEROPAGE 0x00 diff --git a/src/include/access/transam.h b/src/include/access/transam.h index 522c1040737..d25a2dd2073 100644 --- a/src/include/access/transam.h +++ b/src/include/access/transam.h @@ -134,6 +134,12 @@ typedef struct VariableCacheData */ TransactionId latestCompletedXid; /* newest XID that has committed or * aborted */ + + /* + * These fields are protected by CLogTruncationLock + */ + TransactionId oldestClogXid; /* oldest it's safe to look up in clog */ + } VariableCacheData; typedef VariableCacheData *VariableCache; @@ -173,6 +179,7 @@ extern TransactionId GetNewTransactionId(bool isSubXact); extern TransactionId ReadNewTransactionId(void); extern void SetTransactionIdLimit(TransactionId oldest_datfrozenxid, Oid oldest_datoid); +extern void AdvanceOldestClogXid(TransactionId oldest_datfrozenxid); extern bool ForceTransactionIdLimitUpdate(void); extern Oid GetNewObjectId(void); diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h index 7957cab98c6..c09c0f8e5f4 100644 --- a/src/include/access/xlog_internal.h +++ b/src/include/access/xlog_internal.h @@ -31,7 +31,7 @@ /* * Each page of XLOG file has a header like this: */ -#define XLOG_PAGE_MAGIC 0xD096 /* can be used as WAL version indicator */ +#define XLOG_PAGE_MAGIC 0xD097 /* can be used as WAL version indicator */ typedef struct XLogPageHeaderData { |