From 18f7f3920983d5bd1172daf4cd888e147aef190c Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Wed, 16 Jan 2019 00:03:13 +0100
Subject: [PATCH 7/7] Store ispell in shared location tweaks

---
 doc/src/sgml/textsearch.sgml      | 18 ++++++++++--------
 src/backend/tsearch/dict_ispell.c |  2 ++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/doc/src/sgml/textsearch.sgml b/doc/src/sgml/textsearch.sgml
index 0f172eda04..8cceef3aa7 100644
--- a/doc/src/sgml/textsearch.sgml
+++ b/doc/src/sgml/textsearch.sgml
@@ -3114,14 +3114,16 @@ CREATE TEXT SEARCH DICTIONARY english_stem (
    <title>Dictionaries in Shared Memory</title>

    <para>
-    Some dictionaries, especially <application>Ispell</application>, consumes
-    a significant amount of memory, in some cases tens of megabytes.  Most of
-    them store the data in text files, and building the in-memory structure is
-    both CPU and time-consuming.  Instead of doing this in each backend when
-    it needs a dictionary for the first time, the compiled dictionary may be
-    stored in dynamic shared memory so that it may be reused by other backends.
-    Currently only <application>Ispell</application> supports loading into
-    dynamic shared memory.
+    Dictionaries, especially <application>Ispell</application>, may be quite
+    expensive both in terms of memory and CPU usage.  For large dictionaries
+    it may take multiple seconds to read and process input text files on first
+    access, and the in-memory representation may require tens of megabytes.
+    When each backend processes the dictionaries independently and stores them
+    in private memory, this cost is significant.  To amortize it, the compiled
+    dictionary may be stored in shared memory for reuse by other backends.
+    Currently only <application>Ispell</application> supports such sharing.
+
+    XXX "supported" is not the same as "all ispell dicts behave like that".
    </para>
   </sect2>

diff --git a/src/backend/tsearch/dict_ispell.c b/src/backend/tsearch/dict_ispell.c
index 3c9dd78c56..ae2463e2dc 100644
--- a/src/backend/tsearch/dict_ispell.c
+++ b/src/backend/tsearch/dict_ispell.c
@@ -9,6 +9,8 @@
  * of memory exceeds max_shared_dictionaries_size, then the dictionary will be
  * allocated in private backend memory (in dictCtx context).
  *
+ * XXX There's no max_shared_dictionaries_size anymore.
+ *
  * All necessary data are built within dispell_build() function. But
  * structures for regular expressions are compiled on first demand and
  * stored using AffixReg array. It is because regex_t and Regis cannot be
-- 
2.17.2