Avoid useless buffer allocations during binary COPY FROM.

The raw_buf and line_buf buffers aren't used when reading binary format,
so skip allocating them.  raw_buf is 64K so that seems like a worthwhile
savings.  An unused line_buf only wastes 1K, but as long as we're checking
it's free to avoid allocating that too.

Bharath Rupireddy, tweaked a bit by me

Discussion: https://postgr.es/m/CALj2ACXcCKaGPY0whowqrJ4OPJvDnTssgpGCzvuFQu5z0CXb-g@mail.gmail.com

diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 3e199bdfd0c6520a455f821df8acfedc0df76ede..99d14571801224ba8cfe4bf87829ae0ec8db2e65 100644 (file)
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -193,6 +193,9 @@ typedef struct CopyStateData
     * the current line.  The CopyReadAttributes functions return arrays of
     * pointers into this buffer.  We avoid palloc/pfree overhead by re-using
     * the buffer on each cycle.
+    *
+    * (In binary COPY FROM, attribute_buf holds the binary data for the
+    * current field, while the other variables are not used.)
     */
    StringInfoData attribute_buf;
 
@@ -3359,12 +3362,19 @@ BeginCopyFrom(ParseState *pstate,
    cstate->cur_attname = NULL;
    cstate->cur_attval = NULL;
 
-   /* Set up variables to avoid per-attribute overhead. */
+   /*
+    * Set up variables to avoid per-attribute overhead.  attribute_buf is
+    * used in both text and binary modes, but we use line_buf and raw_buf
+    * only in text mode.
+    */
    initStringInfo(&cstate->attribute_buf);
-   initStringInfo(&cstate->line_buf);
-   cstate->line_buf_converted = false;
-   cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);
-   cstate->raw_buf_index = cstate->raw_buf_len = 0;
+   if (!cstate->binary)
+   {
+       initStringInfo(&cstate->line_buf);
+       cstate->line_buf_converted = false;
+       cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);
+       cstate->raw_buf_index = cstate->raw_buf_len = 0;
+   }
 
    /* Assign range table, we'll need it in CopyFrom. */
    if (pstate)