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Diffstat (limited to '')
| -rw-r--r-- | src/backend/utils/adt/xid.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/src/backend/utils/adt/xid.c b/src/backend/utils/adt/xid.c new file mode 100644 index 0000000..faa7737 --- /dev/null +++ b/src/backend/utils/adt/xid.c @@ -0,0 +1,349 @@ +/*------------------------------------------------------------------------- + * + * xid.c + * POSTGRES transaction identifier and command identifier datatypes. + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/utils/adt/xid.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include <limits.h> + +#include "access/multixact.h" +#include "access/transam.h" +#include "access/xact.h" +#include "libpq/pqformat.h" +#include "utils/builtins.h" +#include "utils/xid8.h" + +#define PG_GETARG_COMMANDID(n) DatumGetCommandId(PG_GETARG_DATUM(n)) +#define PG_RETURN_COMMANDID(x) return CommandIdGetDatum(x) + + +Datum +xidin(PG_FUNCTION_ARGS) +{ + char *str = PG_GETARG_CSTRING(0); + + PG_RETURN_TRANSACTIONID((TransactionId) strtoul(str, NULL, 0)); +} + +Datum +xidout(PG_FUNCTION_ARGS) +{ + TransactionId transactionId = PG_GETARG_TRANSACTIONID(0); + char *result = (char *) palloc(16); + + snprintf(result, 16, "%lu", (unsigned long) transactionId); + PG_RETURN_CSTRING(result); +} + +/* + * xidrecv - converts external binary format to xid + */ +Datum +xidrecv(PG_FUNCTION_ARGS) +{ + StringInfo buf = (StringInfo) PG_GETARG_POINTER(0); + + PG_RETURN_TRANSACTIONID((TransactionId) pq_getmsgint(buf, sizeof(TransactionId))); +} + +/* + * xidsend - converts xid to binary format + */ +Datum +xidsend(PG_FUNCTION_ARGS) +{ + TransactionId arg1 = PG_GETARG_TRANSACTIONID(0); + StringInfoData buf; + + pq_begintypsend(&buf); + pq_sendint32(&buf, arg1); + PG_RETURN_BYTEA_P(pq_endtypsend(&buf)); +} + +/* + * xideq - are two xids equal? + */ +Datum +xideq(PG_FUNCTION_ARGS) +{ + TransactionId xid1 = PG_GETARG_TRANSACTIONID(0); + TransactionId xid2 = PG_GETARG_TRANSACTIONID(1); + + PG_RETURN_BOOL(TransactionIdEquals(xid1, xid2)); +} + +/* + * xidneq - are two xids different? + */ +Datum +xidneq(PG_FUNCTION_ARGS) +{ + TransactionId xid1 = PG_GETARG_TRANSACTIONID(0); + TransactionId xid2 = PG_GETARG_TRANSACTIONID(1); + + PG_RETURN_BOOL(!TransactionIdEquals(xid1, xid2)); +} + +/* + * xid_age - compute age of an XID (relative to latest stable xid) + */ +Datum +xid_age(PG_FUNCTION_ARGS) +{ + TransactionId xid = PG_GETARG_TRANSACTIONID(0); + TransactionId now = GetStableLatestTransactionId(); + + /* Permanent XIDs are always infinitely old */ + if (!TransactionIdIsNormal(xid)) + PG_RETURN_INT32(INT_MAX); + + PG_RETURN_INT32((int32) (now - xid)); +} + +/* + * mxid_age - compute age of a multi XID (relative to latest stable mxid) + */ +Datum +mxid_age(PG_FUNCTION_ARGS) +{ + TransactionId xid = PG_GETARG_TRANSACTIONID(0); + MultiXactId now = ReadNextMultiXactId(); + + if (!MultiXactIdIsValid(xid)) + PG_RETURN_INT32(INT_MAX); + + PG_RETURN_INT32((int32) (now - xid)); +} + +/* + * xidComparator + * qsort comparison function for XIDs + * + * We can't use wraparound comparison for XIDs because that does not respect + * the triangle inequality! Any old sort order will do. + */ +int +xidComparator(const void *arg1, const void *arg2) +{ + TransactionId xid1 = *(const TransactionId *) arg1; + TransactionId xid2 = *(const TransactionId *) arg2; + + if (xid1 > xid2) + return 1; + if (xid1 < xid2) + return -1; + return 0; +} + +/* + * xidLogicalComparator + * qsort comparison function for XIDs + * + * This is used to compare only XIDs from the same epoch (e.g. for backends + * running at the same time). So there must be only normal XIDs, so there's + * no issue with triangle inequality. + */ +int +xidLogicalComparator(const void *arg1, const void *arg2) +{ + TransactionId xid1 = *(const TransactionId *) arg1; + TransactionId xid2 = *(const TransactionId *) arg2; + + Assert(TransactionIdIsNormal(xid1)); + Assert(TransactionIdIsNormal(xid2)); + + if (TransactionIdPrecedes(xid1, xid2)) + return -1; + + if (TransactionIdPrecedes(xid2, xid1)) + return 1; + + return 0; +} + +Datum +xid8toxid(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid = PG_GETARG_FULLTRANSACTIONID(0); + + PG_RETURN_TRANSACTIONID(XidFromFullTransactionId(fxid)); +} + +Datum +xid8in(PG_FUNCTION_ARGS) +{ + char *str = PG_GETARG_CSTRING(0); + + PG_RETURN_FULLTRANSACTIONID(FullTransactionIdFromU64(pg_strtouint64(str, NULL, 0))); +} + +Datum +xid8out(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid = PG_GETARG_FULLTRANSACTIONID(0); + char *result = (char *) palloc(21); + + snprintf(result, 21, UINT64_FORMAT, U64FromFullTransactionId(fxid)); + PG_RETURN_CSTRING(result); +} + +Datum +xid8recv(PG_FUNCTION_ARGS) +{ + StringInfo buf = (StringInfo) PG_GETARG_POINTER(0); + uint64 value; + + value = (uint64) pq_getmsgint64(buf); + PG_RETURN_FULLTRANSACTIONID(FullTransactionIdFromU64(value)); +} + +Datum +xid8send(PG_FUNCTION_ARGS) +{ + FullTransactionId arg1 = PG_GETARG_FULLTRANSACTIONID(0); + StringInfoData buf; + + pq_begintypsend(&buf); + pq_sendint64(&buf, (uint64) U64FromFullTransactionId(arg1)); + PG_RETURN_BYTEA_P(pq_endtypsend(&buf)); +} + +Datum +xid8eq(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(FullTransactionIdEquals(fxid1, fxid2)); +} + +Datum +xid8ne(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(!FullTransactionIdEquals(fxid1, fxid2)); +} + +Datum +xid8lt(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(FullTransactionIdPrecedes(fxid1, fxid2)); +} + +Datum +xid8gt(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(FullTransactionIdFollows(fxid1, fxid2)); +} + +Datum +xid8le(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(FullTransactionIdPrecedesOrEquals(fxid1, fxid2)); +} + +Datum +xid8ge(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + PG_RETURN_BOOL(FullTransactionIdFollowsOrEquals(fxid1, fxid2)); +} + +Datum +xid8cmp(PG_FUNCTION_ARGS) +{ + FullTransactionId fxid1 = PG_GETARG_FULLTRANSACTIONID(0); + FullTransactionId fxid2 = PG_GETARG_FULLTRANSACTIONID(1); + + if (FullTransactionIdFollows(fxid1, fxid2)) + PG_RETURN_INT32(1); + else if (FullTransactionIdEquals(fxid1, fxid2)) + PG_RETURN_INT32(0); + else + PG_RETURN_INT32(-1); +} + +/***************************************************************************** + * COMMAND IDENTIFIER ROUTINES * + *****************************************************************************/ + +/* + * cidin - converts CommandId to internal representation. + */ +Datum +cidin(PG_FUNCTION_ARGS) +{ + char *str = PG_GETARG_CSTRING(0); + + PG_RETURN_COMMANDID((CommandId) strtoul(str, NULL, 0)); +} + +/* + * cidout - converts a cid to external representation. + */ +Datum +cidout(PG_FUNCTION_ARGS) +{ + CommandId c = PG_GETARG_COMMANDID(0); + char *result = (char *) palloc(16); + + snprintf(result, 16, "%lu", (unsigned long) c); + PG_RETURN_CSTRING(result); +} + +/* + * cidrecv - converts external binary format to cid + */ +Datum +cidrecv(PG_FUNCTION_ARGS) +{ + StringInfo buf = (StringInfo) PG_GETARG_POINTER(0); + + PG_RETURN_COMMANDID((CommandId) pq_getmsgint(buf, sizeof(CommandId))); +} + +/* + * cidsend - converts cid to binary format + */ +Datum +cidsend(PG_FUNCTION_ARGS) +{ + CommandId arg1 = PG_GETARG_COMMANDID(0); + StringInfoData buf; + + pq_begintypsend(&buf); + pq_sendint32(&buf, arg1); + PG_RETURN_BYTEA_P(pq_endtypsend(&buf)); +} + +Datum +cideq(PG_FUNCTION_ARGS) +{ + CommandId arg1 = PG_GETARG_COMMANDID(0); + CommandId arg2 = PG_GETARG_COMMANDID(1); + + PG_RETURN_BOOL(arg1 == arg2); +} |