Fix description of I/O timing info for shared buffers in EXPLAIN (BUFFERS)

This fixes an error introduced by efb0ef909f60, that changed the
description of this field to "shared/local" while these I/O timings
relate to shared buffers.  This information is available when
track_io_timing is enabled.  Note that HEAD has added new counters for
local buffers in 295c36c0c1fa, so there is no need to touch it.  The
description is updated to "shared" to be compatible with HEAD.

Per discussion with Nazir Bilal Yavuz and Hubert Depesz Lubaczewski,
whose EXPLAIN analyzer tool was not actually able to parse the previous
term because of the slash character.

Discussion: https://postgr.es/m/ZTCTiUqm_H3iBihl@paquier.xyz
Backpatch-through: 15

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 8570b14f6217bc1e8f193578f433d8aa2a7b4eaa..6c2e5c8a4f9a3bd11fa946807ae1c83ba8e5d374 100644 (file)
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -3632,7 +3632,7 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 
            if (has_timing)
            {
-               appendStringInfoString(es->str, " shared/local");
+               appendStringInfoString(es->str, " shared");
                if (!INSTR_TIME_IS_ZERO(usage->blk_read_time))
                    appendStringInfo(es->str, " read=%0.3f",
                                     INSTR_TIME_GET_MILLISEC(usage->blk_read_time));