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Diffstat (limited to 'src/include/replication/reorderbuffer.h')
| -rw-r--r-- | src/include/replication/reorderbuffer.h | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/src/include/replication/reorderbuffer.h b/src/include/replication/reorderbuffer.h new file mode 100644 index 00000000000..01eabfb7be7 --- /dev/null +++ b/src/include/replication/reorderbuffer.h @@ -0,0 +1,351 @@ +/* + * reorderbuffer.h + * PostgreSQL logical replay/reorder buffer management. + * + * Copyright (c) 2012-2014, PostgreSQL Global Development Group + * + * src/include/replication/reorderbuffer.h + */ +#ifndef REORDERBUFFER_H +#define REORDERBUFFER_H + +#include "access/htup_details.h" + +#include "lib/ilist.h" + +#include "storage/sinval.h" + +#include "utils/hsearch.h" +#include "utils/rel.h" +#include "utils/snapshot.h" +#include "utils/timestamp.h" + +/* an individual tuple, stored in one chunk of memory */ +typedef struct ReorderBufferTupleBuf +{ + /* position in preallocated list */ + slist_node node; + + /* tuple, stored sequentially */ + HeapTupleData tuple; + HeapTupleHeaderData header; + char data[MaxHeapTupleSize]; +} ReorderBufferTupleBuf; + +/* types of the change passed to a 'change' callback */ +enum ReorderBufferChangeType +{ + REORDER_BUFFER_CHANGE_INSERT, + REORDER_BUFFER_CHANGE_UPDATE, + REORDER_BUFFER_CHANGE_DELETE +}; + +/* + * a single 'change', can be an insert (with one tuple), an update (old, new), + * or a delete (old). + * + * The same struct is also used internally for other purposes but that should + * never be visible outside reorderbuffer.c. + */ +typedef struct ReorderBufferChange +{ + XLogRecPtr lsn; + + /* type of change */ + union + { + enum ReorderBufferChangeType action; + /* do not leak internal enum values to the outside */ + int action_internal; + }; + + /* + * Context data for the change, which part of the union is valid depends + * on action/action_internal. + */ + union + { + /* old, new tuples when action == *_INSERT|UPDATE|DELETE */ + struct + { + /* relation that has been changed */ + RelFileNode relnode; + /* valid for DELETE || UPDATE */ + ReorderBufferTupleBuf *oldtuple; + /* valid for INSERT || UPDATE */ + ReorderBufferTupleBuf *newtuple; + } tp; + + /* new snapshot */ + Snapshot snapshot; + + /* new command id for existing snapshot in a catalog changing tx */ + CommandId command_id; + + /* new cid mapping for catalog changing transaction */ + struct + { + RelFileNode node; + ItemPointerData tid; + CommandId cmin; + CommandId cmax; + CommandId combocid; + } tuplecid; + }; + + /* + * While in use this is how a change is linked into a transactions, + * otherwise it's the preallocated list. + */ + dlist_node node; +} ReorderBufferChange; + +typedef struct ReorderBufferTXN +{ + /* + * The transactions transaction id, can be a toplevel or sub xid. + */ + TransactionId xid; + + /* did the TX have catalog changes */ + bool has_catalog_changes; + + /* + * Do we know this is a subxact? + */ + bool is_known_as_subxact; + + /* + * LSN of the first data carrying, WAL record with knowledge about this + * xid. This is allowed to *not* be first record adorned with this xid, if + * the previous records aren't relevant for logical decoding. + */ + XLogRecPtr first_lsn; + + /* ---- + * LSN of the record that lead to this xact to be committed or + * aborted. This can be a + * * plain commit record + * * plain commit record, of a parent transaction + * * prepared transaction commit + * * plain abort record + * * prepared transaction abort + * * error during decoding + * ---- + */ + XLogRecPtr final_lsn; + + /* + * LSN pointing to the end of the commit record + 1. + */ + XLogRecPtr end_lsn; + + /* + * LSN of the last lsn at which snapshot information reside, so we can + * restart decoding from there and fully recover this transaction from + * WAL. + */ + XLogRecPtr restart_decoding_lsn; + + /* + * Commit time, only known when we read the actual commit record. + */ + TimestampTz commit_time; + + /* + * Base snapshot or NULL. + */ + Snapshot base_snapshot; + XLogRecPtr base_snapshot_lsn; + + /* + * How many ReorderBufferChange's do we have in this txn. + * + * Changes in subtransactions are *not* included but tracked separately. + */ + uint64 nentries; + + /* + * How many of the above entries are stored in memory in contrast to being + * spilled to disk. + */ + uint64 nentries_mem; + + /* + * List of ReorderBufferChange structs, including new Snapshots and new + * CommandIds + */ + dlist_head changes; + + /* + * List of (relation, ctid) => (cmin, cmax) mappings for catalog tuples. + * Those are always assigned to the toplevel transaction. (Keep track of + * #entries to create a hash of the right size) + */ + dlist_head tuplecids; + uint64 ntuplecids; + + /* + * On-demand built hash for looking up the above values. + */ + HTAB *tuplecid_hash; + + /* + * Hash containing (potentially partial) toast entries. NULL if no toast + * tuples have been found for the current change. + */ + HTAB *toast_hash; + + /* + * non-hierarchical list of subtransactions that are *not* aborted. Only + * used in toplevel transactions. + */ + dlist_head subtxns; + uint32 nsubtxns; + + /* + * Stored cache invalidations. This is not a linked list because we get + * all the invalidations at once. + */ + uint32 ninvalidations; + SharedInvalidationMessage *invalidations; + + /* --- + * Position in one of three lists: + * * list of subtransactions if we are *known* to be subxact + * * list of toplevel xacts (can be a as-yet unknown subxact) + * * list of preallocated ReorderBufferTXNs + * --- + */ + dlist_node node; + +} ReorderBufferTXN; + +/* so we can define the callbacks used inside struct ReorderBuffer itself */ +typedef struct ReorderBuffer ReorderBuffer; + +/* change callback signature */ +typedef void (*ReorderBufferApplyChangeCB) ( + ReorderBuffer *rb, + ReorderBufferTXN *txn, + Relation relation, + ReorderBufferChange *change); + +/* begin callback signature */ +typedef void (*ReorderBufferBeginCB) ( + ReorderBuffer *rb, + ReorderBufferTXN *txn); + +/* commit callback signature */ +typedef void (*ReorderBufferCommitCB) ( + ReorderBuffer *rb, + ReorderBufferTXN *txn, + XLogRecPtr commit_lsn); + +struct ReorderBuffer +{ + /* + * xid => ReorderBufferTXN lookup table + */ + HTAB *by_txn; + + /* + * Transactions that could be a toplevel xact, ordered by LSN of the first + * record bearing that xid.. + */ + dlist_head toplevel_by_lsn; + + /* + * one-entry sized cache for by_txn. Very frequently the same txn gets + * looked up over and over again. + */ + TransactionId by_txn_last_xid; + ReorderBufferTXN *by_txn_last_txn; + + /* + * Callacks to be called when a transactions commits. + */ + ReorderBufferBeginCB begin; + ReorderBufferApplyChangeCB apply_change; + ReorderBufferCommitCB commit; + + /* + * Pointer that will be passed untouched to the callbacks. + */ + void *private_data; + + /* + * Private memory context. + */ + MemoryContext context; + + /* + * Data structure slab cache. + * + * We allocate/deallocate some structures very frequently, to avoid bigger + * overhead we cache some unused ones here. + * + * The maximum number of cached entries is controlled by const variables + * ontop of reorderbuffer.c + */ + + /* cached ReorderBufferTXNs */ + dlist_head cached_transactions; + Size nr_cached_transactions; + + /* cached ReorderBufferChanges */ + dlist_head cached_changes; + Size nr_cached_changes; + + /* cached ReorderBufferTupleBufs */ + slist_head cached_tuplebufs; + Size nr_cached_tuplebufs; + + XLogRecPtr current_restart_decoding_lsn; + + /* buffer for disk<->memory conversions */ + char *outbuf; + Size outbufsize; +}; + + +ReorderBuffer *ReorderBufferAllocate(void); +void ReorderBufferFree(ReorderBuffer *); + +ReorderBufferTupleBuf *ReorderBufferGetTupleBuf(ReorderBuffer *); +void ReorderBufferReturnTupleBuf(ReorderBuffer *, ReorderBufferTupleBuf *tuple); +ReorderBufferChange *ReorderBufferGetChange(ReorderBuffer *); +void ReorderBufferReturnChange(ReorderBuffer *, ReorderBufferChange *); + +void ReorderBufferQueueChange(ReorderBuffer *, TransactionId, XLogRecPtr lsn, ReorderBufferChange *); +void ReorderBufferCommit(ReorderBuffer *, TransactionId, + XLogRecPtr commit_lsn, XLogRecPtr end_lsn, + TimestampTz commit_time); +void ReorderBufferAssignChild(ReorderBuffer *, TransactionId, TransactionId, XLogRecPtr commit_lsn); +void ReorderBufferCommitChild(ReorderBuffer *, TransactionId, TransactionId, + XLogRecPtr commit_lsn, XLogRecPtr end_lsn); +void ReorderBufferAbort(ReorderBuffer *, TransactionId, XLogRecPtr lsn); +void ReorderBufferAbortOld(ReorderBuffer *, TransactionId xid); +void ReorderBufferForget(ReorderBuffer *, TransactionId, XLogRecPtr lsn); + +void ReorderBufferSetBaseSnapshot(ReorderBuffer *, TransactionId, XLogRecPtr lsn, struct SnapshotData *snap); +void ReorderBufferAddSnapshot(ReorderBuffer *, TransactionId, XLogRecPtr lsn, struct SnapshotData *snap); +void ReorderBufferAddNewCommandId(ReorderBuffer *, TransactionId, XLogRecPtr lsn, + CommandId cid); +void ReorderBufferAddNewTupleCids(ReorderBuffer *, TransactionId, XLogRecPtr lsn, + RelFileNode node, ItemPointerData pt, + CommandId cmin, CommandId cmax, CommandId combocid); +void ReorderBufferAddInvalidations(ReorderBuffer *, TransactionId, XLogRecPtr lsn, + Size nmsgs, SharedInvalidationMessage *msgs); +bool ReorderBufferIsXidKnown(ReorderBuffer *, TransactionId xid); +void ReorderBufferXidSetCatalogChanges(ReorderBuffer *, TransactionId xid, XLogRecPtr lsn); +bool ReorderBufferXidHasCatalogChanges(ReorderBuffer *, TransactionId xid); +bool ReorderBufferXidHasBaseSnapshot(ReorderBuffer *, TransactionId xid); + +ReorderBufferTXN *ReorderBufferGetOldestTXN(ReorderBuffer *); + +void ReorderBufferSetRestartPoint(ReorderBuffer *, XLogRecPtr ptr); + +void StartupReorderBuffer(void); + +#endif |