Add a debugging option to stress-test outfuncs.c and readfuncs.c.
In the normal course of operation, query trees will be serialized only if they are stored as views or rules; and plan trees will be serialized only if they get passed to parallel-query workers. This leaves an awful lot of opportunity for bugs/oversights to not get detected, as indeed we've just been reminded of the hard way. To improve matters, this patch adds a new compile option WRITE_READ_PARSE_PLAN_TREES, which is modeled on the longstanding option COPY_PARSE_PLAN_TREES; but instead of passing all parse and plan trees through copyObject, it passes them through nodeToString + stringToNode. Enabling this option in a buildfarm animal or two will catch problems at least for cases that are exercised by the regression tests. A small problem with this idea is that readfuncs.c historically has discarded location fields, on the reasonable grounds that parse locations in a retrieved view are not relevant to the current query. But doing that in WRITE_READ_PARSE_PLAN_TREES breaks pg_stat_statements, and it could cause problems for future improvements that might try to report error locations at runtime. To fix that, provide a variant behavior in readfuncs.c that makes it restore location fields when told to. In passing, const-ify the string arguments of stringToNode and its subsidiary functions, just because it annoyed me that they weren't const already. Discussion: https://postgr.es/m/17114.1537138992@sss.pgh.pa.us
This commit is contained in:
Tom Lane
parent
db1071d4ee
commit
d0cfc3d6a4
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@ -28,18 +28,30 @@
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/* Static state for pg_strtok */
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static char *pg_strtok_ptr = NULL;
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static const char *pg_strtok_ptr = NULL;
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/* State flag that determines how readfuncs.c should treat location fields */
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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bool restore_location_fields = false;
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#endif
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/*
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* stringToNode -
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* returns a Node with a given legal ASCII representation
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* builds a Node tree from its string representation (assumed valid)
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*
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* restore_loc_fields instructs readfuncs.c whether to restore location
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* fields rather than set them to -1. This is currently only supported
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* in builds with the WRITE_READ_PARSE_PLAN_TREES debugging flag set.
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*/
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void *
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stringToNode(char *str)
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static void *
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stringToNodeInternal(const char *str, bool restore_loc_fields)
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{
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char *save_strtok;
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void *retval;
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const char *save_strtok;
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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bool save_restore_location_fields;
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#endif
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/*
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* We save and restore the pre-existing state of pg_strtok. This makes the
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@ -51,13 +63,45 @@ stringToNode(char *str)
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pg_strtok_ptr = str; /* point pg_strtok at the string to read */
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/*
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* If enabled, likewise save/restore the location field handling flag.
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*/
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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save_restore_location_fields = restore_location_fields;
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restore_location_fields = restore_loc_fields;
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#endif
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retval = nodeRead(NULL, 0); /* do the reading */
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pg_strtok_ptr = save_strtok;
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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restore_location_fields = save_restore_location_fields;
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#endif
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return retval;
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}
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/*
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* Externally visible entry points
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*/
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void *
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stringToNode(const char *str)
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{
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return stringToNodeInternal(str, false);
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}
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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void *
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stringToNodeWithLocations(const char *str)
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{
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return stringToNodeInternal(str, true);
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}
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#endif
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/*****************************************************************************
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*
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* the lisp token parser
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@ -104,11 +148,11 @@ stringToNode(char *str)
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* code should add backslashes to a string constant to ensure it is treated
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* as a single token.
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*/
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char *
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const char *
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pg_strtok(int *length)
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{
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char *local_str; /* working pointer to string */
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char *ret_str; /* start of token to return */
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const char *local_str; /* working pointer to string */
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const char *ret_str; /* start of token to return */
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local_str = pg_strtok_ptr;
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@ -166,7 +210,7 @@ pg_strtok(int *length)
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* any protective backslashes in the token are removed.
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*/
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char *
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debackslash(char *token, int length)
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debackslash(const char *token, int length)
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{
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char *result = palloc(length + 1);
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char *ptr = result;
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@ -198,10 +242,10 @@ debackslash(char *token, int length)
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* Assumption: the ascii representation is legal
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*/
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static NodeTag
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nodeTokenType(char *token, int length)
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nodeTokenType(const char *token, int length)
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{
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NodeTag retval;
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char *numptr;
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const char *numptr;
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int numlen;
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/*
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@ -269,7 +313,7 @@ nodeTokenType(char *token, int length)
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* this should only be invoked from within a stringToNode operation).
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*/
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void *
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nodeRead(char *token, int tok_len)
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nodeRead(const char *token, int tok_len)
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{
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Node *result;
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NodeTag type;
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@ -17,10 +17,14 @@
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* never read executor state trees, either.
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*
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* Parse location fields are written out by outfuncs.c, but only for
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* possible debugging use. When reading a location field, we discard
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* debugging use. When reading a location field, we normally discard
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* the stored value and set the location field to -1 (ie, "unknown").
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* This is because nodes coming from a stored rule should not be thought
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* to have a known location in the current query's text.
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* However, if restore_location_fields is true, we do restore location
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* fields from the string. This is currently intended only for use by the
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* WRITE_READ_PARSE_PLAN_TREES test code, which doesn't want to cause
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* any change in the node contents.
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*
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*-------------------------------------------------------------------------
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*/
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@ -51,7 +55,7 @@
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/* And a few guys need only the pg_strtok support fields */
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#define READ_TEMP_LOCALS() \
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char *token; \
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const char *token; \
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int length
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/* ... but most need both */
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@ -120,12 +124,19 @@
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token = pg_strtok(&length); /* get field value */ \
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local_node->fldname = nullable_string(token, length)
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/* Read a parse location field (and throw away the value, per notes above) */
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/* Read a parse location field (and possibly throw away the value) */
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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#define READ_LOCATION_FIELD(fldname) \
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token = pg_strtok(&length); /* skip :fldname */ \
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token = pg_strtok(&length); /* get field value */ \
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local_node->fldname = restore_location_fields ? atoi(token) : -1
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#else
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#define READ_LOCATION_FIELD(fldname) \
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token = pg_strtok(&length); /* skip :fldname */ \
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token = pg_strtok(&length); /* get field value */ \
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(void) token; /* in case not used elsewhere */ \
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local_node->fldname = -1 /* set field to "unknown" */
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#endif
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/* Read a Node field */
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#define READ_NODE_FIELD(fldname) \
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@ -2804,7 +2815,7 @@ readDatum(bool typbyval)
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Size length,
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i;
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int tokenLength;
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char *token;
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const char *token;
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Datum res;
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char *s;
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@ -2817,7 +2828,7 @@ readDatum(bool typbyval)
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token = pg_strtok(&tokenLength); /* read the '[' */
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if (token == NULL || token[0] != '[')
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elog(ERROR, "expected \"[\" to start datum, but got \"%s\"; length = %zu",
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token ? (const char *) token : "[NULL]", length);
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token ? token : "[NULL]", length);
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if (typbyval)
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{
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@ -2847,7 +2858,7 @@ readDatum(bool typbyval)
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token = pg_strtok(&tokenLength); /* read the ']' */
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if (token == NULL || token[0] != ']')
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elog(ERROR, "expected \"]\" to end datum, but got \"%s\"; length = %zu",
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token ? (const char *) token : "[NULL]", length);
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token ? token : "[NULL]", length);
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return res;
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}
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@ -2860,7 +2871,7 @@ readAttrNumberCols(int numCols)
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{
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int tokenLength,
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i;
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char *token;
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const char *token;
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AttrNumber *attr_vals;
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if (numCols <= 0)
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@ -2884,7 +2895,7 @@ readOidCols(int numCols)
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{
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int tokenLength,
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i;
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char *token;
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const char *token;
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Oid *oid_vals;
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if (numCols <= 0)
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@ -2908,7 +2919,7 @@ readIntCols(int numCols)
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{
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int tokenLength,
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i;
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char *token;
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const char *token;
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int *int_vals;
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if (numCols <= 0)
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@ -2932,7 +2943,7 @@ readBoolCols(int numCols)
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{
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int tokenLength,
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i;
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char *token;
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const char *token;
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bool *bool_vals;
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if (numCols <= 0)
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@ -1335,7 +1335,6 @@ addRangeTableEntryForSubquery(ParseState *pstate,
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Assert(pstate != NULL);
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rte->rtekind = RTE_SUBQUERY;
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rte->relid = InvalidOid;
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rte->subquery = subquery;
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rte->alias = alias;
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@ -633,6 +633,12 @@ pg_parse_query(const char *query_string)
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}
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#endif
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/*
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* Currently, outfuncs/readfuncs support is missing for many raw parse
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* tree nodes, so we don't try to implement WRITE_READ_PARSE_PLAN_TREES
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* here.
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*/
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TRACE_POSTGRESQL_QUERY_PARSE_DONE(query_string);
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return raw_parsetree_list;
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@ -763,7 +769,7 @@ pg_rewrite_query(Query *query)
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ShowUsage("REWRITER STATISTICS");
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#ifdef COPY_PARSE_PLAN_TREES
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/* Optional debugging check: pass querytree output through copyObject() */
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/* Optional debugging check: pass querytree through copyObject() */
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{
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List *new_list;
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@ -776,6 +782,46 @@ pg_rewrite_query(Query *query)
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}
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#endif
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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/* Optional debugging check: pass querytree through outfuncs/readfuncs */
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{
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List *new_list = NIL;
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ListCell *lc;
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/*
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* We currently lack outfuncs/readfuncs support for most utility
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* statement types, so only attempt to write/read non-utility queries.
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*/
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foreach(lc, querytree_list)
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{
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Query *query = castNode(Query, lfirst(lc));
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if (query->commandType != CMD_UTILITY)
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{
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char *str = nodeToString(query);
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Query *new_query = stringToNodeWithLocations(str);
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/*
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* queryId is not saved in stored rules, but we must preserve
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* it here to avoid breaking pg_stat_statements.
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*/
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new_query->queryId = query->queryId;
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new_list = lappend(new_list, new_query);
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pfree(str);
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}
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else
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new_list = lappend(new_list, query);
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}
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/* This checks both outfuncs/readfuncs and the equal() routines... */
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if (!equal(new_list, querytree_list))
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elog(WARNING, "outfuncs/readfuncs failed to produce equal parse tree");
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else
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querytree_list = new_list;
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}
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#endif
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if (Debug_print_rewritten)
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elog_node_display(LOG, "rewritten parse tree", querytree_list,
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Debug_pretty_print);
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@ -812,7 +858,7 @@ pg_plan_query(Query *querytree, int cursorOptions, ParamListInfo boundParams)
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ShowUsage("PLANNER STATISTICS");
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#ifdef COPY_PARSE_PLAN_TREES
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/* Optional debugging check: pass plan output through copyObject() */
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/* Optional debugging check: pass plan tree through copyObject() */
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{
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PlannedStmt *new_plan = copyObject(plan);
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@ -830,6 +876,30 @@ pg_plan_query(Query *querytree, int cursorOptions, ParamListInfo boundParams)
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}
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#endif
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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/* Optional debugging check: pass plan tree through outfuncs/readfuncs */
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{
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char *str;
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PlannedStmt *new_plan;
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str = nodeToString(plan);
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new_plan = stringToNodeWithLocations(str);
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pfree(str);
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/*
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* equal() currently does not have routines to compare Plan nodes, so
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* don't try to test equality here. Perhaps fix someday?
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*/
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#ifdef NOT_USED
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/* This checks both outfuncs/readfuncs and the equal() routines... */
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if (!equal(new_plan, plan))
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elog(WARNING, "outfuncs/readfuncs failed to produce an equal plan tree");
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else
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#endif
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plan = new_plan;
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}
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#endif
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/*
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* Print plan if debugging.
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*/
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@ -610,7 +610,10 @@ extern char *bmsToString(const struct Bitmapset *bms);
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/*
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* nodes/{readfuncs.c,read.c}
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*/
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extern void *stringToNode(char *str);
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extern void *stringToNode(const char *str);
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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extern void *stringToNodeWithLocations(const char *str);
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#endif
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extern struct Bitmapset *readBitmapset(void);
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extern uintptr_t readDatum(bool typbyval);
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extern bool *readBoolCols(int numCols);
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@ -16,12 +16,19 @@
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#include "nodes/nodes.h"
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/*
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* variable in read.c that needs to be accessible to readfuncs.c
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*/
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#ifdef WRITE_READ_PARSE_PLAN_TREES
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extern bool restore_location_fields;
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#endif
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/*
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* prototypes for functions in read.c (the lisp token parser)
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*/
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extern char *pg_strtok(int *length);
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extern char *debackslash(char *token, int length);
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extern void *nodeRead(char *token, int tok_len);
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extern const char *pg_strtok(int *length);
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extern char *debackslash(const char *token, int length);
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extern void *nodeRead(const char *token, int tok_len);
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/*
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* prototypes for functions in readfuncs.c
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@ -286,6 +286,13 @@
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*/
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/* #define COPY_PARSE_PLAN_TREES */
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/*
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* Define this to force all parse and plan trees to be passed through
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* outfuncs.c/readfuncs.c, to facilitate catching errors and omissions in
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* those modules.
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*/
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/* #define WRITE_READ_PARSE_PLAN_TREES */
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/*
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* Define this to force all raw parse trees for DML statements to be scanned
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* by raw_expression_tree_walker(), to facilitate catching errors and
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Loading…
Reference in New Issue