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commit    199d449c076a8564a9e8b113818f71c43f59d4cd
Author:   Robert Haas <rhaas@postgresql.org>
Date:     Fri Jun 17 18:28:45 2011 +0000
First released in: 9.2.0, 8.2.22, 8.3.16, 8.4.9, 9.0.5, 9.1.0

    Add overflow checks to int4 and int8 versions of generate_series().
    
    The previous code went into an infinite loop after overflow.  In fact,
    an overflow is not really an error; it just means that the current
    value is the last one we need to return.  So, just arrange to stop
    immediately when overflow is detected.
    
    Back-patch all the way.


 src/backend/utils/adt/int.c  | 4 ++++
 src/backend/utils/adt/int8.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/backend/utils/adt/int.c b/src/backend/utils/adt/int.c
index 47a0bd2a801..8bf3751cdc8 100644
--- a/src/backend/utils/adt/int.c
+++ b/src/backend/utils/adt/int.c
@@ -1470,6 +1470,10 @@ generate_series_step_int4(PG_FUNCTION_ARGS)
 		/* increment current in preparation for next iteration */
 		fctx->current += fctx->step;
 
+		/* if next-value computation overflows, this is the final result */
+		if (SAMESIGN(result, fctx->step) && !SAMESIGN(result, fctx->current))
+			fctx->step = 0;
+
 		/* do when there is more left to send */
 		SRF_RETURN_NEXT(funcctx, Int32GetDatum(result));
 	}
diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index 5901d407de1..876b2d97f1c 100644
--- a/src/backend/utils/adt/int8.c
+++ b/src/backend/utils/adt/int8.c
@@ -1268,6 +1268,10 @@ generate_series_step_int8(PG_FUNCTION_ARGS)
 		/* increment current in preparation for next iteration */
 		fctx->current += fctx->step;
 
+		/* if next-value computation overflows, this is the final result */
+		if (SAMESIGN(result, fctx->step) && !SAMESIGN(result, fctx->current))
+			fctx->step = 0;
+
 		/* do when there is more left to send */
 		SRF_RETURN_NEXT(funcctx, Int64GetDatum(result));
 	}


[parent: 07bc6fe6687f]