diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/nodes/queryjumblefuncs.c | 140 | ||||
| -rw-r--r-- | src/include/nodes/queryjumble.h | 12 |
2 files changed, 132 insertions, 20 deletions
diff --git a/src/backend/nodes/queryjumblefuncs.c b/src/backend/nodes/queryjumblefuncs.c index 62d6cfb7ac1..c1d72765567 100644 --- a/src/backend/nodes/queryjumblefuncs.c +++ b/src/backend/nodes/queryjumblefuncs.c @@ -58,8 +58,11 @@ bool query_id_squash_values = false; */ bool query_id_enabled = false; +static JumbleState *InitJumble(void); +static uint64 DoJumble(JumbleState *jstate, Node *node); static void AppendJumble(JumbleState *jstate, const unsigned char *item, Size size); +static void FlushPendingNulls(JumbleState *jstate); static void RecordConstLocation(JumbleState *jstate, int location, bool merged); static void _jumbleNode(JumbleState *jstate, Node *node); @@ -120,29 +123,22 @@ CleanQuerytext(const char *query, int *location, int *len) return query; } +/* + * JumbleQuery + * Recursively process the given Query producing a 64-bit hash value by + * hashing the relevant fields and record that value in the Query's queryId + * field. Return the JumbleState object used for jumbling the query. + */ JumbleState * JumbleQuery(Query *query) { - JumbleState *jstate = NULL; + JumbleState *jstate; Assert(IsQueryIdEnabled()); - jstate = (JumbleState *) palloc(sizeof(JumbleState)); + jstate = InitJumble(); - /* Set up workspace for query jumbling */ - jstate->jumble = (unsigned char *) palloc(JUMBLE_SIZE); - jstate->jumble_len = 0; - jstate->clocations_buf_size = 32; - jstate->clocations = (LocationLen *) - palloc(jstate->clocations_buf_size * sizeof(LocationLen)); - jstate->clocations_count = 0; - jstate->highest_extern_param_id = 0; - - /* Compute query ID and mark the Query node with it */ - _jumbleNode(jstate, (Node *) query); - query->queryId = DatumGetUInt64(hash_any_extended(jstate->jumble, - jstate->jumble_len, - 0)); + query->queryId = DoJumble(jstate, (Node *) query); /* * If we are unlucky enough to get a hash of zero, use 1 instead for @@ -173,11 +169,59 @@ EnableQueryId(void) } /* - * AppendJumble: Append a value that is substantive in a given query to - * the current jumble. + * InitJumble + * Allocate a JumbleState object and make it ready to jumble. */ -static void -AppendJumble(JumbleState *jstate, const unsigned char *item, Size size) +static JumbleState * +InitJumble(void) +{ + JumbleState *jstate; + + jstate = (JumbleState *) palloc(sizeof(JumbleState)); + + /* Set up workspace for query jumbling */ + jstate->jumble = (unsigned char *) palloc(JUMBLE_SIZE); + jstate->jumble_len = 0; + jstate->clocations_buf_size = 32; + jstate->clocations = (LocationLen *) palloc(jstate->clocations_buf_size * + sizeof(LocationLen)); + jstate->clocations_count = 0; + jstate->highest_extern_param_id = 0; + jstate->pending_nulls = 0; +#ifdef USE_ASSERT_CHECKING + jstate->total_jumble_len = 0; +#endif + + return jstate; +} + +/* + * DoJumble + * Jumble the given Node using the given JumbleState and return the resulting + * jumble hash. + */ +static uint64 +DoJumble(JumbleState *jstate, Node *node) +{ + /* Jumble the given node */ + _jumbleNode(jstate, node); + + /* Flush any pending NULLs before doing the final hash */ + if (jstate->pending_nulls > 0) + FlushPendingNulls(jstate); + + /* Process the jumble buffer and produce the hash value */ + return DatumGetUInt64(hash_any_extended(jstate->jumble, + jstate->jumble_len, + 0)); +} + +/* + * AppendJumbleInternal: Internal function for appending to the jumble buffer + */ +static pg_attribute_always_inline void +AppendJumbleInternal(JumbleState *jstate, const unsigned char *item, + Size size) { unsigned char *jumble = jstate->jumble; Size jumble_len = jstate->jumble_len; @@ -205,11 +249,56 @@ AppendJumble(JumbleState *jstate, const unsigned char *item, Size size) jumble_len += part_size; item += part_size; size -= part_size; + +#ifdef USE_ASSERT_CHECKING + jstate->total_jumble_len += part_size; +#endif } + jstate->jumble_len = jumble_len; } /* + * AppendJumble + * Add 'size' bytes of the given jumble 'value' to the jumble state + */ +static pg_noinline void +AppendJumble(JumbleState *jstate, const unsigned char *value, Size size) +{ + if (jstate->pending_nulls > 0) + FlushPendingNulls(jstate); + + AppendJumbleInternal(jstate, value, size); +} + +/* + * AppendJumbleNull + * For jumbling NULL pointers + */ +static pg_attribute_always_inline void +AppendJumbleNull(JumbleState *jstate) +{ + jstate->pending_nulls++; +} + +/* + * FlushPendingNulls + * Incorporate the pending_null value into the jumble buffer. + * + * Note: Callers must ensure that there's at least 1 pending NULL. + */ +static pg_attribute_always_inline void +FlushPendingNulls(JumbleState *jstate) +{ + Assert(jstate->pending_nulls > 0); + + AppendJumbleInternal(jstate, + (const unsigned char *) &jstate->pending_nulls, 4); + jstate->pending_nulls = 0; +} + + +/* * Record location of constant within query string of query tree that is * currently being walked. * @@ -335,6 +424,8 @@ IsSquashableConstList(List *elements, Node **firstExpr, Node **lastExpr) do { \ if (expr->str) \ AppendJumble(jstate, (const unsigned char *) (expr->str), strlen(expr->str) + 1); \ + else \ + AppendJumbleNull(jstate); \ } while(0) /* Function name used for the node field attribute custom_query_jumble. */ #define JUMBLE_CUSTOM(nodetype, item) \ @@ -385,9 +476,15 @@ static void _jumbleNode(JumbleState *jstate, Node *node) { Node *expr = node; +#ifdef USE_ASSERT_CHECKING + Size prev_jumble_len = jstate->total_jumble_len; +#endif if (expr == NULL) + { + AppendJumbleNull(jstate); return; + } /* Guard against stack overflow due to overly complex expressions */ check_stack_depth(); @@ -435,6 +532,9 @@ _jumbleNode(JumbleState *jstate, Node *node) default: break; } + + /* Ensure we added something to the jumble buffer */ + Assert(jstate->total_jumble_len > prev_jumble_len); } static void diff --git a/src/include/nodes/queryjumble.h b/src/include/nodes/queryjumble.h index 905f66bc0bd..62794c5a901 100644 --- a/src/include/nodes/queryjumble.h +++ b/src/include/nodes/queryjumble.h @@ -54,6 +54,18 @@ typedef struct JumbleState /* highest Param id we've seen, in order to start normalization correctly */ int highest_extern_param_id; + + /* + * Count of the number of NULL nodes seen since last appending a value. + * These are flushed out to the jumble buffer before subsequent appends + * and before performing the final jumble hash. + */ + unsigned int pending_nulls; + +#ifdef USE_ASSERT_CHECKING + /* The total number of bytes added to the jumble buffer */ + Size total_jumble_len; +#endif } JumbleState; /* Values for the compute_query_id GUC */ |