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-rw-r--r--src/include/nodes/lockoptions.h61
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diff --git a/src/include/nodes/lockoptions.h b/src/include/nodes/lockoptions.h
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+/*-------------------------------------------------------------------------
+ *
+ * lockoptions.h
+ * Common header for some locking-related declarations.
+ *
+ *
+ * Copyright (c) 2014-2021, PostgreSQL Global Development Group
+ *
+ * src/include/nodes/lockoptions.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef LOCKOPTIONS_H
+#define LOCKOPTIONS_H
+
+/*
+ * This enum represents the different strengths of FOR UPDATE/SHARE clauses.
+ * The ordering here is important, because the highest numerical value takes
+ * precedence when a RTE is specified multiple ways. See applyLockingClause.
+ */
+typedef enum LockClauseStrength
+{
+ LCS_NONE, /* no such clause - only used in PlanRowMark */
+ LCS_FORKEYSHARE, /* FOR KEY SHARE */
+ LCS_FORSHARE, /* FOR SHARE */
+ LCS_FORNOKEYUPDATE, /* FOR NO KEY UPDATE */
+ LCS_FORUPDATE /* FOR UPDATE */
+} LockClauseStrength;
+
+/*
+ * This enum controls how to deal with rows being locked by FOR UPDATE/SHARE
+ * clauses (i.e., it represents the NOWAIT and SKIP LOCKED options).
+ * The ordering here is important, because the highest numerical value takes
+ * precedence when a RTE is specified multiple ways. See applyLockingClause.
+ */
+typedef enum LockWaitPolicy
+{
+ /* Wait for the lock to become available (default behavior) */
+ LockWaitBlock,
+ /* Skip rows that can't be locked (SKIP LOCKED) */
+ LockWaitSkip,
+ /* Raise an error if a row cannot be locked (NOWAIT) */
+ LockWaitError
+} LockWaitPolicy;
+
+/*
+ * Possible lock modes for a tuple.
+ */
+typedef enum LockTupleMode
+{
+ /* SELECT FOR KEY SHARE */
+ LockTupleKeyShare,
+ /* SELECT FOR SHARE */
+ LockTupleShare,
+ /* SELECT FOR NO KEY UPDATE, and UPDATEs that don't modify key columns */
+ LockTupleNoKeyExclusive,
+ /* SELECT FOR UPDATE, UPDATEs that modify key columns, and DELETE */
+ LockTupleExclusive
+} LockTupleMode;
+
+#endif /* LOCKOPTIONS_H */