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e55704d8b2
When wal_level=logical, we'll log columns from the old tuple as configured by the REPLICA IDENTITY facility added in commit 07cacba983ef79be4a84fcd0e0ca3b5fcb85dd65. This makes it possible a properly-configured logical replication solution to correctly follow table updates even if they change the chosen key columns, or, with REPLICA IDENTITY FULL, even if the table has no key at all. Note that updates which do not modify the replica identity column won't log anything extra, making the choice of a good key (i.e. one that will rarely be changed) important to performance when wal_level=logical is configured. Each insert, update, or delete to a catalog table will also log the CMIN and/or CMAX values of stamped by the current transaction. This is necessary because logical decoding will require access to historical snapshots of the catalog in order to decode some data types, and the CMIN/CMAX values that we may need in order to judge row visibility may have been overwritten by the time we need them. Andres Freund, reviewed in various versions by myself, Heikki Linnakangas, KONDO Mitsumasa, and many others.
262 lines
8.7 KiB
C
262 lines
8.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* xact.h
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* postgres transaction system definitions
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*
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*
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* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/access/xact.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef XACT_H
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#define XACT_H
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#include "access/xlog.h"
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#include "nodes/pg_list.h"
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#include "storage/relfilenode.h"
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/*
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* Xact isolation levels
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*/
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#define XACT_READ_UNCOMMITTED 0
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#define XACT_READ_COMMITTED 1
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#define XACT_REPEATABLE_READ 2
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#define XACT_SERIALIZABLE 3
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extern int DefaultXactIsoLevel;
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extern PGDLLIMPORT int XactIsoLevel;
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/*
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* We implement three isolation levels internally.
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* The two stronger ones use one snapshot per database transaction;
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* the others use one snapshot per statement.
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* Serializable uses predicate locks in addition to snapshots.
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* These macros should be used to check which isolation level is selected.
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*/
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#define IsolationUsesXactSnapshot() (XactIsoLevel >= XACT_REPEATABLE_READ)
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#define IsolationIsSerializable() (XactIsoLevel == XACT_SERIALIZABLE)
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/* Xact read-only state */
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extern bool DefaultXactReadOnly;
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extern bool XactReadOnly;
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/*
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* Xact is deferrable -- only meaningful (currently) for read only
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* SERIALIZABLE transactions
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*/
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extern bool DefaultXactDeferrable;
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extern bool XactDeferrable;
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typedef enum
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{
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SYNCHRONOUS_COMMIT_OFF, /* asynchronous commit */
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SYNCHRONOUS_COMMIT_LOCAL_FLUSH, /* wait for local flush only */
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SYNCHRONOUS_COMMIT_REMOTE_WRITE, /* wait for local flush and remote
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* write */
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SYNCHRONOUS_COMMIT_REMOTE_FLUSH /* wait for local and remote flush */
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} SyncCommitLevel;
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/* Define the default setting for synchonous_commit */
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#define SYNCHRONOUS_COMMIT_ON SYNCHRONOUS_COMMIT_REMOTE_FLUSH
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/* Synchronous commit level */
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extern int synchronous_commit;
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/* Kluge for 2PC support */
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extern bool MyXactAccessedTempRel;
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/*
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* start- and end-of-transaction callbacks for dynamically loaded modules
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*/
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typedef enum
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{
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XACT_EVENT_COMMIT,
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XACT_EVENT_ABORT,
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XACT_EVENT_PREPARE,
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XACT_EVENT_PRE_COMMIT,
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XACT_EVENT_PRE_PREPARE
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} XactEvent;
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typedef void (*XactCallback) (XactEvent event, void *arg);
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typedef enum
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{
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SUBXACT_EVENT_START_SUB,
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SUBXACT_EVENT_COMMIT_SUB,
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SUBXACT_EVENT_ABORT_SUB,
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SUBXACT_EVENT_PRE_COMMIT_SUB
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} SubXactEvent;
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typedef void (*SubXactCallback) (SubXactEvent event, SubTransactionId mySubid,
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SubTransactionId parentSubid, void *arg);
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/* ----------------
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* transaction-related XLOG entries
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* ----------------
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*/
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/*
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* XLOG allows to store some information in high 4 bits of log
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* record xl_info field
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*/
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#define XLOG_XACT_COMMIT 0x00
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#define XLOG_XACT_PREPARE 0x10
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#define XLOG_XACT_ABORT 0x20
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#define XLOG_XACT_COMMIT_PREPARED 0x30
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#define XLOG_XACT_ABORT_PREPARED 0x40
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#define XLOG_XACT_ASSIGNMENT 0x50
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#define XLOG_XACT_COMMIT_COMPACT 0x60
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typedef struct xl_xact_assignment
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{
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TransactionId xtop; /* assigned XID's top-level XID */
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int nsubxacts; /* number of subtransaction XIDs */
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TransactionId xsub[1]; /* assigned subxids */
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} xl_xact_assignment;
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#define MinSizeOfXactAssignment offsetof(xl_xact_assignment, xsub)
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typedef struct xl_xact_commit_compact
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{
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TimestampTz xact_time; /* time of commit */
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int nsubxacts; /* number of subtransaction XIDs */
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/* ARRAY OF COMMITTED SUBTRANSACTION XIDs FOLLOWS */
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TransactionId subxacts[1]; /* VARIABLE LENGTH ARRAY */
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} xl_xact_commit_compact;
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#define MinSizeOfXactCommitCompact offsetof(xl_xact_commit_compact, subxacts)
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typedef struct xl_xact_commit
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{
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TimestampTz xact_time; /* time of commit */
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uint32 xinfo; /* info flags */
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int nrels; /* number of RelFileNodes */
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int nsubxacts; /* number of subtransaction XIDs */
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int nmsgs; /* number of shared inval msgs */
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Oid dbId; /* MyDatabaseId */
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Oid tsId; /* MyDatabaseTableSpace */
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/* Array of RelFileNode(s) to drop at commit */
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RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
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/* ARRAY OF COMMITTED SUBTRANSACTION XIDs FOLLOWS */
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/* ARRAY OF SHARED INVALIDATION MESSAGES FOLLOWS */
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} xl_xact_commit;
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#define MinSizeOfXactCommit offsetof(xl_xact_commit, xnodes)
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/*
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* These flags are set in the xinfo fields of WAL commit records,
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* indicating a variety of additional actions that need to occur
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* when emulating transaction effects during recovery.
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* They are named XactCompletion... to differentiate them from
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* EOXact... routines which run at the end of the original
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* transaction completion.
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*/
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#define XACT_COMPLETION_UPDATE_RELCACHE_FILE 0x01
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#define XACT_COMPLETION_FORCE_SYNC_COMMIT 0x02
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/* Access macros for above flags */
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#define XactCompletionRelcacheInitFileInval(xinfo) (xinfo & XACT_COMPLETION_UPDATE_RELCACHE_FILE)
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#define XactCompletionForceSyncCommit(xinfo) (xinfo & XACT_COMPLETION_FORCE_SYNC_COMMIT)
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typedef struct xl_xact_abort
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{
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TimestampTz xact_time; /* time of abort */
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int nrels; /* number of RelFileNodes */
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int nsubxacts; /* number of subtransaction XIDs */
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/* Array of RelFileNode(s) to drop at abort */
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RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
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/* ARRAY OF ABORTED SUBTRANSACTION XIDs FOLLOWS */
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} xl_xact_abort;
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/* Note the intentional lack of an invalidation message array c.f. commit */
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#define MinSizeOfXactAbort offsetof(xl_xact_abort, xnodes)
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/*
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* COMMIT_PREPARED and ABORT_PREPARED are identical to COMMIT/ABORT records
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* except that we have to store the XID of the prepared transaction explicitly
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* --- the XID in the record header will be for the transaction doing the
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* COMMIT PREPARED or ABORT PREPARED command.
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*/
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typedef struct xl_xact_commit_prepared
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{
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TransactionId xid; /* XID of prepared xact */
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xl_xact_commit crec; /* COMMIT record */
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/* MORE DATA FOLLOWS AT END OF STRUCT */
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} xl_xact_commit_prepared;
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#define MinSizeOfXactCommitPrepared offsetof(xl_xact_commit_prepared, crec.xnodes)
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typedef struct xl_xact_abort_prepared
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{
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TransactionId xid; /* XID of prepared xact */
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xl_xact_abort arec; /* ABORT record */
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/* MORE DATA FOLLOWS AT END OF STRUCT */
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} xl_xact_abort_prepared;
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#define MinSizeOfXactAbortPrepared offsetof(xl_xact_abort_prepared, arec.xnodes)
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/* ----------------
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* extern definitions
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* ----------------
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*/
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extern bool IsTransactionState(void);
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extern bool IsAbortedTransactionBlockState(void);
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extern TransactionId GetTopTransactionId(void);
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extern TransactionId GetTopTransactionIdIfAny(void);
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extern TransactionId GetCurrentTransactionId(void);
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extern TransactionId GetCurrentTransactionIdIfAny(void);
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extern TransactionId GetStableLatestTransactionId(void);
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extern SubTransactionId GetCurrentSubTransactionId(void);
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extern void MarkCurrentTransactionIdLoggedIfAny(void);
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extern bool SubTransactionIsActive(SubTransactionId subxid);
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extern CommandId GetCurrentCommandId(bool used);
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extern TimestampTz GetCurrentTransactionStartTimestamp(void);
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extern TimestampTz GetCurrentStatementStartTimestamp(void);
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extern TimestampTz GetCurrentTransactionStopTimestamp(void);
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extern void SetCurrentStatementStartTimestamp(void);
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extern int GetCurrentTransactionNestLevel(void);
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extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
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extern void CommandCounterIncrement(void);
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extern void ForceSyncCommit(void);
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extern void StartTransactionCommand(void);
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extern void CommitTransactionCommand(void);
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extern void AbortCurrentTransaction(void);
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extern void BeginTransactionBlock(void);
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extern bool EndTransactionBlock(void);
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extern bool PrepareTransactionBlock(char *gid);
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extern void UserAbortTransactionBlock(void);
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extern void ReleaseSavepoint(List *options);
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extern void DefineSavepoint(char *name);
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extern void RollbackToSavepoint(List *options);
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extern void BeginInternalSubTransaction(char *name);
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extern void ReleaseCurrentSubTransaction(void);
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extern void RollbackAndReleaseCurrentSubTransaction(void);
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extern bool IsSubTransaction(void);
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extern bool IsTransactionBlock(void);
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extern bool IsTransactionOrTransactionBlock(void);
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extern char TransactionBlockStatusCode(void);
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extern void AbortOutOfAnyTransaction(void);
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extern void PreventTransactionChain(bool isTopLevel, const char *stmtType);
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extern void RequireTransactionChain(bool isTopLevel, const char *stmtType);
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extern void WarnNoTransactionChain(bool isTopLevel, const char *stmtType);
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extern bool IsInTransactionChain(bool isTopLevel);
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extern void RegisterXactCallback(XactCallback callback, void *arg);
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extern void UnregisterXactCallback(XactCallback callback, void *arg);
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extern void RegisterSubXactCallback(SubXactCallback callback, void *arg);
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extern void UnregisterSubXactCallback(SubXactCallback callback, void *arg);
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extern int xactGetCommittedChildren(TransactionId **ptr);
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extern void xact_redo(XLogRecPtr lsn, XLogRecord *record);
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extern void xact_desc(StringInfo buf, uint8 xl_info, char *rec);
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#endif /* XACT_H */
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