pgq.insert_event: support working with pgq 2.x schema

this allows to upgrade module without uprading schema.

1 files changed, 34 insertions, 1 deletions

diff --git a/sql/pgq/lowlevel/insert_event.c b/sql/pgq/lowlevel/insert_event.c
index f63890d8..b5e673be 100644
--- a/sql/pgq/lowlevel/insert_event.c
+++ b/sql/pgq/lowlevel/insert_event.c
@@ -64,6 +64,21 @@ PG_FUNCTION_INFO_V1(pgq_insert_event_raw);
 #define COL_LIMIT	6
 
 /*
+ * Support inserting into pgq 2 queues.
+ */
+#define QUEUE_SQL_OLD \
+	"select queue_id::int4, queue_data_pfx::text," \
+	" queue_cur_table::int4, nextval(queue_event_seq)::int8," \
+	" false::bool as queue_disable_insert," \
+	" null::int4 as queue_per_tx_limit" \
+	" from pgq.queue where queue_name = $1"
+
+#define QUEUE_CHECK_NEW \
+	"select 1 from pg_catalog.pg_attribute" \
+	" where attname = 'queue_per_tx_limit'" \
+	" and attrelid = 'pgq.queue'::regclass"
+
+/*
  * Plan cache entry in HTAB.
  */
 struct InsertCacheEntry {
@@ -91,6 +106,7 @@ struct QueueState {
 /*
  * Cached plans.
  */
+static void *queue_check_plan;
 static void *queue_plan;
 static HTAB *insert_cache;
 
@@ -103,15 +119,32 @@ static void init_cache(void)
 	Oid types[1] = { TEXTOID };
 	HASHCTL ctl;
 	int flags;
+	int res;
 	int max_queues = 128;
+	const char *sql;
 
 	if (init_done)
 		return;
 
 	/*
+	 * Check if old (v2.x) or new (v3.x) queue table.
+	 *
+	 * Needed for upgrades.
+	 */
+	res = SPI_execute(QUEUE_CHECK_NEW, 1, 0);
+	if (res < 0)
+		elog(ERROR, "pgq.insert_event: QUEUE_CHECK_NEW failed");
+
+	if (SPI_processed > 0) {
+		sql = QUEUE_SQL;
+	} else {
+		sql = QUEUE_SQL_OLD;
+	}
+
+	/*
 	 * Init plans.
 	 */
-	queue_plan = SPI_saveplan(SPI_prepare(QUEUE_SQL, 1, types));
+	queue_plan = SPI_saveplan(SPI_prepare(sql, 1, types));
 	if (queue_plan == NULL)
 		elog(ERROR, "pgq_insert: SPI_prepare() failed");