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Create a new expression node type RelabelType, which exists solely to
represent the result of a binary-compatible type coercion. At runtime it just evaluates its argument --- but during type resolution, exprType will pick up the output type of the RelabelType node instead of the type of the argument. This solves some longstanding problems with dropped type coercions, an example being 'select now()::abstime::int4' which used to produce date-formatted output, not an integer, because the coercion to int4 was dropped on the floor.
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.84 2000/02/15 20:49:12 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.85 2000/02/20 21:32:05 tgl Exp $
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*
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* NOTES
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* Most of the read functions for plan nodes are tested. (In fact, they
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@ -1191,6 +1191,35 @@ _readSubLink()
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return local_node;
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}
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/* ----------------
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* _readRelabelType
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*
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* RelabelType is a subclass of Node
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* ----------------
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*/
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static RelabelType *
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_readRelabelType()
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{
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RelabelType *local_node;
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char *token;
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int length;
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local_node = makeNode(RelabelType);
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token = lsptok(NULL, &length); /* eat :arg */
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local_node->arg = nodeRead(true); /* now read it */
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token = lsptok(NULL, &length); /* eat :resulttype */
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token = lsptok(NULL, &length); /* get resulttype */
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local_node->resulttype = (Oid) atol(token);
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token = lsptok(NULL, &length); /* eat :resulttypmod */
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token = lsptok(NULL, &length); /* get resulttypmod */
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local_node->resulttypmod = atoi(token);
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return local_node;
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}
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/*
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* Stuff from execnodes.h
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*/
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@ -1820,6 +1849,8 @@ parsePlanString(void)
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return_value = _readAggref();
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else if (length == 7 && strncmp(token, "SUBLINK", length) == 0)
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return_value = _readSubLink();
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else if (length == 11 && strncmp(token, "RELABELTYPE", length) == 0)
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return_value = _readRelabelType();
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else if (length == 3 && strncmp(token, "AGG", length) == 0)
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return_value = _readAgg();
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else if (length == 4 && strncmp(token, "HASH", length) == 0)
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